sailing yacht a speed

Sail GP: how do supercharged racing yachts go so fast? An engineer explains

Head of Engineering, Warsash School of Maritime Science and Engineering, Solent University

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Jonathan Ridley does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

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Sailing used to be considered as a rather sedate pastime. But in the past few years, the world of yacht racing has been revolutionised by the arrival of hydrofoil-supported catamarans, known as “foilers”. These vessels, more akin to high-performance aircraft than yachts, combine the laws of aerodynamics and hydrodynamics to create vessels capable of speeds of up to 50 knots, which is far faster than the wind propelling them.

An F50 catamaran preparing for the Sail GP series recently even broke this barrier, reaching an incredible speed of 50.22 knots (57.8mph) purely powered by the wind. This was achieved in a wind of just 19.3 knots (22.2mph). F50s are 15-metre-long, 8.8-metre-wide hydrofoil catamarans propelled by rigid sails and capable of such astounding speeds that Sail GP has been called the “ Formula One of sailing ”. How are these yachts able to go so fast? The answer lies in some simple fluid dynamics.

As a vessel’s hull moves through the water, there are two primary physical mechanisms that create drag and slow the vessel down. To build a faster boat you have to find ways to overcome the drag force.

The first mechanism is friction. As the water flows past the hull, a microscopic layer of water is effectively attached to the hull and is pulled along with the yacht. A second layer of water then attaches to the first layer, and the sliding or shearing between them creates friction.

On the outside of this is a third layer, which slides over the inner layers creating more friction, and so on. Together, these layers are known as the boundary layer – and it’s the shearing of the boundary layer’s molecules against each other that creates frictional drag.

A yacht also makes waves as it pushes the water around and under the hull from the bow (front) to the stern (back) of the boat. The waves form two distinctive patterns around the yacht (one at each end), known as Kelvin Wave patterns.

These waves, which move at the same speed as the yacht, are very energetic. This creates drag on the boat known as the wave-making drag, which is responsible for around 90% of the total drag. As the yacht accelerates to faster speeds (close to the “hull speed”, explained later), these waves get higher and longer.

These two effects combine to produce a phenomenon known as “ hull speed ”, which is the fastest the boat can travel – and in conventional single-hull yachts it is very slow. A single-hull yacht of the same size as the F50 has a hull speed of around 12 mph.

However, it’s possible to reduce both the frictional and wave-making drag and overcome this hull-speed limit by building a yacht with hydrofoils . Hydrofoils are small, underwater wings. These act in the same way as an aircraft wing, creating a lift force which acts against gravity, lifting our yacht upwards so that the hull is clear of the water.

While an aircraft’s wings are very large, the high density of water compared to air means that we only need very small hydrofoils to produce a lot of the important lift force. A hydrofoil just the size of three A3 sheets of paper, when moving at just 10 mph, can produce enough lift to pick up a large person.

This significantly reduces the surface area and the volume of the boat that is underwater, which cuts the frictional drag and the wave-making drag, respectively. The combined effect is a reduction in the overall drag to a fraction of its original amount, so that the yacht is capable of sailing much faster than it could without hydrofoils.

The other innovation that helps boost the speed of racing yachts is the use of rigid sails . The power available from traditional sails to drive the boat forward is relatively small, limited by the fact that the sail’s forces have to act in equilibrium with a range of other forces, and that fabric sails do not make an ideal shape for creating power. Rigid sails, which are very similar in design to an aircraft wing, form a much more efficient shape than traditional sails, effectively giving the yacht a larger engine and more power.

As the yacht accelerates from the driving force of these sails, it experiences what is known as “ apparent wind ”. Imagine a completely calm day, with no wind. As you walk, you experience a breeze in your face at the same speed that you are walking. If there was a wind blowing too, you would feel a mixture of the real (or “true” wind) and the breeze you have generated.

The two together form the apparent wind, which can be faster than the true wind. If there is enough true wind combined with this apparent wind, then significant force and power can be generated from the sail to propel the yacht, so it can easily sail faster than the wind speed itself.

The combined effect of reducing the drag and increasing the driving power results in a yacht that is far faster than those of even a few years ago. But all of this would not be possible without one further advance: materials. In order to be able to “fly”, the yacht must have a low mass, and the hydrofoil itself must be very strong. To achieve the required mass, strength and rigidity using traditional boat-building materials such as wood or aluminium would be very difficult.

This is where modern advanced composite materials such as carbon fibre come in. Production techniques optimising weight, rigidity and strength allow the production of structures that are strong and light enough to produce incredible yachts like the F50.

The engineers who design these high-performance boats (known as naval architects ) are always looking to use new materials and science to get an optimum design. In theory, the F50 should be able to go even faster.

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The top 10 fastest superyachts in the world

Despite their larger size, superyachts can still reach an impressive speed on the water – as this official list of the world’s fastest superyachts shows. For over 20 years, the 41.5-metre Izar -built yacht Foners had been outpacing her contenders with top speeds of 70 knots – equivalent to 80 miles per hour – and lay claim to the world's speediest superyacht title. But in 2023, a new contender swooped in and cinched first place. Described as a "hyper muscle yacht", the Bolide 80 entered the scene with a rapid 73-knot maximum speed.

Their challengers are not far behind. For adrenaline-seekers with a need for speed, get your pulses racing with our definitive list of the quickest superyachts on the water.

Bolide 80 | 73 knots

Built in 2023, the 24.9-metre Bolide 80 model holds the title for the fastest superyacht in the world, narrowly pipping the long-time champion, Foners , to the post. The "hyper muscle yacht" hits a blistering top speed of 73 knots with propulsion deriving from triple MAN 12 V 2000 diesel engines, each delivering around 2,000 horsepower. In terms of range, she is predicted to deliver 200 nautical miles at maximum speed, with a range of 345 nautical miles at a cruising speed of 55 knots.

Everything about the yacht's design has been carefully considered, from its aerodynamic-engineered exterior to the way it harnesses foiling technology. At the intersection of performance and avant-garde design, the Bolide 80 is able to hit the impressive top speed thanks to its "multi-stepped" planing hull that generates low frictional resistance. In terms of fuel consumption, she consumes 11 litres per mile at 40 knots, 13 litres per mile at 55 knots and 16 litres per mile at 70 knots.

The interior configuration on hull one – a collaboration between Stefano Faggioni and Victory's internal design team – features an owner's cabin in the most forward part of the hull. Meanwhile, the main saloon is located on the lower deck amidships, which can be transformed into a second cabin if needed.

• Builder: Bolide Yachts
• Country of build: Italy
• Delivery year: 2023
• Length Overall: 24.9 m
• Beam: 5.4 m

More about this yacht

Yachts for sale, more stories, foners | 70.1 knots.

Clocking in at a thrilling 70.1 knots, the 41.5-metre Foners once raced to the top spot as the world’s fastest superyacht but is now narrowly trumped by the Bolide 100. She’s been difficult to catch up with, having maintained her position since her delivery in 2000. 

Her zippy speed is produced by two 1,280hp MAN engines coupled with three Rolls Royce 6,700hp gas turbines that drive three KaMeWa water jets. But she is not just about speed; her interior, designed by Studio Spadolini is quite literally fit for a king. Originally built by Spanish shipyard Izar as the King of Spain’s royal yacht , the DLBA-designed Foners features interiors finished in elegant gloss sycamore wood panelling with stitched tan leather detailing. She can accommodate eight guests and six crew on board, and her superstructure has been lined with Aramid fibre for the express purpose of making it bullet proof. There is a formal dining room indoors, while the deck spaces are vast offering plenty of opportunities for al fresco entertaining. At a cruising speed of 12 knots, she has a range of 1,800 nautical miles.

• Builder: Izar
• Country of build: Spain
• Delivery year: 2000
• Length Overall: 41.5 m
• Beam: 9.2 m
• Gross Tonnage 180 t

World Is Not Enough | 67 Knots

World Is Not Enough comes third to Foners by just a fraction, able to reach a respectable top speed of 67 knots. She was delivered in 2004 by Millenium Super Yachts and designed by Dutch naval architect Frank Mulder . She is propelled by two Paxman diesel engines and two Lycoming gas turbines, producing a staggering 20,600hp. She also boasts an impressive cruising range of 3,800 nautical miles at a comfortable speed of 10 knots.

World Is Not Enough measures 42.4 metres LOA and can accommodate 10 guests on board in five luxurious cabins, along with seven crew members. When not ploughing through the waves at full throttle, she offers plenty of space for relaxation, with al fresco dining and lounge spaces available on all decks and an additional formal dining space and bar indoors. Her interiors have been designed in a classic style by Evan K. Marshall and feature marble finishes, opulent mirrors and glossy wood panelling. She was last refitted in 2011.

• Builder: Neptunus - Millennium
• Country of build: Netherlands
• Delivery year: 2004
• Length Overall: 42.4 m
• Beam: 8.25 m
• Gross Tonnage 291 t

Galeocerdo | 65 Knots

The sleek lines and futuristic design of Rodriquez Yachts’ Galeocerdo is the result of exhaustive research and design development programme by Wally founder Luca Bassani. Created with the aim of maintaining high speeds in rough seas, the 36-metre Wally Power 118 superyacht was launched in 2003 following tank testing at the SSPA facility in Goteborg, Sweden, and wind tunnel testing at the Ferrari facility in Maranello, Italy. Lazzarini Pickering Architetti and Intermarine also collaborated on the design of Galeocredo .

Galeocerdo is driven to a top speed of 65 knots by three Vericor TF50 gas turbines, each driving a Rolls-Royce Kamewa water jet. The titanium exhaust system is lightweight while extremely resistant to the high temperatures generated by the gas turbines, and can muster up to 16,800hp. At a cruising speed of 45 knots, she can cover a range of 1,500 nautical miles. Her interiors offer room for six guests and six crew on board.

• Builder: Rodriquez Yachts
• Delivery year: 2003
• Length Overall: 36 m

Kereon | 62.3 Knots

Launched in 2004 by Italian yard AB Yachts, Kereon can blast through waves at a top speed of 62.3 knots. This punchy performance is made possible by a triple 6,300hp CRM diesel engine set-up fitted to a fast planing hull designed by naval architect Angelo Arnaboldi . Inside Kereon can accommodate up to six guests in three cabins, while her 12,000-litre fuel tank means a maximum range of 900 nautical miles is possible at her fast cruising speed of 50 knots. The 35.7-metre superyacht features sharp exterior lines and a distinctive metallic silver superstructure that contribute to her sporty allure.

• Builder: AB Yachts - Next Yacht Group
• Length Overall: 27 m
• Beam: 6.4 m

Jet Ruban Bleu | 60 knots

Neck-and-neck with Brave Challenger , Azimut Atlantic Challenger, OCI Ciorinie and the AB100 is the 25-metre Jet Ruban Bleu . Delivered in 1990 by Multiplast , and designed by Gilles Ollier together with Coste Design & Partners , she is powered by a single MTU 3,500hp engine and can reach a top speed of 60 knots. At a speed of 50 knots she has a cruising range of 3,000 nautical miles. She features a planing GRP hull and superstructure, with her decks also constructed from GRP.

• Builder: Multiplast
• Country of build: France
• Delivery year: 1990
• Length Overall: 25 m
• Beam: 4.39 m

AB 100 | 60 knots

Forming part of AB Yachts ' 30-metre AB100 series, sisterships Yunga and El Mirlo secure 10th place in the list of the fastest superyachts in the world. The sportfly models were the first to be launched since the series was redesigned in 2021 and boast impressive credentials: a top speed of 60 knots, cruising speed of 37 knots, and maximum cruising range of 550 nautical miles at 45 knots, with power coming from a pair of MTU diesel engines. The AB100 series is known for its "breathtaking" speeds upwards of 50 knots, which the Viareggio-based shipyard claims can be reached "almost without noticing". Interior design on both yachts is owed to Archea Associati with accommodation for up to 10 guests across four staterooms. 

• Delivery year: 2021
• Length Overall: 30.5 m
• Beam: 6.8 m
• Gross Tonnage 147 t

Oci Ciornie | 60 Knots

Prolific naval architect Don Shead teamed up with American yard Palmer Johnson and Dutch shipbuilders Vripack in 1998 to create Oci Ciornie . This aluminium-hulled speed machine was fitted with twin 1,800hp MTU 16V 2000 M90 engines, a 4,600hp AVCO Lycoming gas turbine and Arneson surface drives for a staggering top speed of 60 knots.

Her interiors can accommodate up to eight guests in three cabins consisting of a master suite, double cabin and twin room with a pair of pullman berths. The deck saloon and forward outside spaces are all located on one level for a streamlined look, and the interior of the main saloon takes design cues from vintage aircraft design. The 25-metre superyacht can also accommodate two crew on board.

• Builder: Palmer Johnson
• Country of build: United States of America
• Delivery year: 1998
• Beam: 6.22 m

Azimut Atlantic Challenger | 60 knots

Designed purely for the purposes of collecting the Blue Riband award, the Azimut Atlantic Challenger was launched by Benetti in 1988 with exterior details by Pininfarina . The 26.82-metre aluminium monohull can reach a top speed of 60 knots under the power of four CRM diesel engines offering 7,400hp. At a cruising speed of 40 knots, she has a range of 3,000 nautical miles. Unfortunately, her attempt to procure the Blue Riband shortly after her launch in 1988 was ultimately fruitless.

• Builder: Benetti
• Delivery year: 1988
• Length Overall: 26.82 m
• Beam: 7.5 m

Brave Challenger | 60 Knots

Powered by three Rolls-Royce Proteus gas turbines totalling 13,500hp, the 31-metre Brave Challenger has proven top speeds of over 60 knots and can achieve higher speeds using its alternative Vosper-developed high-speed propellers.

Built by Vosper Ltd in Portsmouth in 1961, Brave Challenger is the only surviving example of the Brave Class fast-patrol design that was designed and built for the Royal Navy. Built alongside the Royal Navy’s HMS Brave Borderer and HMS Brave Swordsman , Brave Challenger was completed with a special consent of the Admiralty and Royal Navy to be equipped for private use.

First acquired by owner W.G. Haydon-Baillie in 1979, Brave Challenger was rebuilt to flagship standard at a purpose-built facility as part of the Haydon-Baillie Aircraft and Naval Collection in Southampton over a period of 10 years and 2.2 million man hours from 1979 – 1989. From 2017 – 2021, Brave Challenger underwent a full restoration by the Haydon-Baillie Maritime Heritage Team at the superyacht refit yard Trafalgar Shipyard in Portsmouth. Its dedicated support base now includes 54 spare Rolls-Royce Proteus gas turbine engines, extensive spares, 10 spare V-Drive gearboxes and 12 spare propellers.

"Brave Challenger ’s speed of 60-plus knots was officially recorded under Lloyds Supervision over the Measured Mile off Portsmouth, UK – and is fully repeatable at all times as part of its design and everyday operating potential," according to owner W.G Haydon-Baillie. "It is often considered that only the fastest yacht speeds that are officially recorded and are not one-off events – and are fully repeatable as part of the yacht's design and everyday operating potential are relevant to include in the top 10 fastest claims."

• Builder: Vosper
• Country of build: United Kingdom
• Delivery year: 1960
• Length Overall: 31.39 m
• Beam: 7.32 m
• Gross Tonnage 209 t

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Fastest sailboats: The teams aiming to break 80 knots

• April 6, 2022

It's been nearly a decade since Sailrocket set a new record to become the world's fastest sailboat. Now two teams are hoping to set a new record with their radical designs, Mark Chisnell reports

On 24 November 2012, Paul Larsen and his Sailrocket team rewrote our understanding of the physics of sailboats, stamping their names indelibly in the record books as they set a new record for the world’s fastest sailboat.

A little over a week earlier, at a spot called Walvis Bay on the coast of Namibia, Sailrocket 2 had pushed the outright sailing speed record up by the biggest-ever margin – from 55.65 to 59.23 knots. The performance on the 24th smashed it beyond all expectations though, a gloriously windy day that saw Sailrocket 2 deliver a 65.45 knot average officially becoming the world’s fastest sailboat.

It was a remarkable human achievement, piloting a boat down a 500m course at speeds that had previously been thought impossible. “Your job is to go 100% down that course, there’s no halfway about it,” Paul Larsen told me, almost a decade later. “By the time you’ve got a big team and all the momentum of that project going, your biggest fear is not going fast.”

The risks are inescapable though, as Larsen had revealed in a blog; “As I lay awake in bed that morning I considered writing a little note that I hoped would never be read and stashing it somewhere. Too morbid. Just get it right, Larsen.”

Growth of the world’s fastest sailboat

To put Sailrocket’s performance into context you need to consider the trajectory and history of the sailing speed record . It started back in 1972 with Tim Colman and Crossbow setting an opening mark of 26.30 knots.

Yellow Pages in 1993. Photo: Frederick Clement/DPPI Media/Alamy

By 1993, Yellow Pages had upped that all the way to 46.52 knots – an average improvement of almost a knot every year. But then something changes, progress halts for over a decade. The windsurfers and kiteboarders eventually start nudging it back up, but it’s 16 years before another yacht – Alain Thebault’s foil-borne L’Hydroptère – sets a new record, not even five knots quicker than Yellow Pages .

It was thought that the speed of sailing machines was reaching a ceiling, a physical limit defined by the cavitation point. If you have ever made a cup of tea at altitude then you will know that the boiling point (the transformation point where water changes from a liquid into a vapour), varies with pressure. The lower the pressure, the lower the temperature required for water to boil. So, at the top of Everest, water will boil at about 68°C.

There’s also low pressure on the leeward side of an aero- or hydrofoil . Foils provide a lifting force because of the pressure difference between one side and the other. This difference creates the force as the foil tries to equalise the pressure.

L’Hydroptère claimed the record in 2009. Photo: Christophe Launay

If a hydrofoil goes fast enough then the pressure to leeward will drop sufficiently that the water starts to ‘boil’ or vaporise. This creates a loss of lift, and instability as smooth flow turns chaotic, with vapour bubbles flowing down the foil to an area of higher pressure where they collapse.

It’s this speed limit that we see America’s Cup and SailGP foilers hit on a reach. Once the speed gets much above 50 knots the foils – which are designed to suppress cavitation for as long as possible – finally start to cavitate and the boats just can’t go any faster.

To get past this point a completely different type of foil is required, one that does not try to eliminate cavitation but instead tries to stabilise it, and this is the secret to the 65-knot speed of Sailrocket 2 . “That’s the brilliant [foil] design that we settled on, with a lot of help from guys like Aerotrope and Chris Hornzee-Jones. Chris did amazing work behind the scenes on that project, including designing the final foils,” said Larsen.

Article continues below…

Syroco: Radical design aiming to set a new speed record

If having a top-flight speed sailor as a part of your team taking on the challenge of creating the world’s…

SP80: Swiss team hoping to build the fastest sailboat

SP80 was conceived by three graduates of Swiss engineering school, École Polytechnique Fédérale de Lausanne; Benoît Gaudiot, Xavier Lepercq and…

Sailrocket obliterates world record….again

Matthew Sheahan talks to Paul Larsen shortly after he exceeds 65 knots, shattering his own world record

The team realised the foil didn’t need to be impossibly thin to suppress and avoid cavitation. Instead, they could encourage it and push past the cavitation point with a foil that would cavitate in a stable fashion.

“To make a dinghy or a powerboat analogy, it’s like when you get over that hump and the boat gets up on the plane. We all know when the water separates off the back of the boat, you don’t want your transom gurgling around at the back there with all that drag,” Larsen explains.

Current speed record holders Paul Larsen and Vestas Sailrocket 2. Photo: Vestas SailRocket

In a similar fashion, Sailrocket 2 ’s foil is able to shed the turbulent, draggy flow of early cavitation and replace it with a single smooth pocket of vapour around the foil as air sucks down from the surface. Larsen calls this a base ventilated foil, it’s also sometimes termed a super-ventilating foil.

“So you end up with these very shallow camber, base ventilated foils, and they’re not overly efficient but they don’t have a limit,” he explained. “They keep working. It’s like a jet fighter’s wings. They’re not efficient, but if you put a big jet engine behind them, they keep going where the others stop and hit the ceiling.”

Force alignment

The jet engine was the other part of the problem. How do you generate enough power from the aerofoil to push a horribly inefficient hydrofoil up to the speeds required to start cavitation, and then blow through that barrier?

The answer lay in a decades-old idea – force alignment. In conventional sailboats, be they dinghies, multihulls or yachts, the aerodynamic force created by the sails is both pushing the boat forward and pushing it over.

The force is resisted by a combination of a hydrodynamic force from a foil in the water, and weight – either the crew’s bodyweight or the weight of a keel. These two forces act at a distance from the centre of effort of the sail – creating opposing levers, with the forces of mass and hydrodynamic lift opposing the aerodynamic force generated by the sail (or wingsail).

The use of these forces to create a propulsive forward force demands a structure of a commensurate size and strength. So to go faster required more force and/or lighter overall weight, but also stronger structures. It was big improvements in the strength and weight characteristics of materials that allowed much of the jumps in speeds set through the 1970s, 80s and 90s.

Vestas Sailrocket 2 used force alignment to achieve her remarkable speeds

But there was another way: by offsetting the forces and aligning them. “So [you] have the centre of effort of the aerodynamic forces, the sail or the wing, directly aligned with the opposing force of the foil,” explains Larsen. In other words, remove the levers by having the force from the sail directly oppose the force from the hydrofoil.

“We didn’t come up with that concept, that was written about in the 1960s by Bernard Smith in the book The 40-Knot Sailboat ,” Larsen adds. Smith’s insights were so far ahead of his time that it took almost five decades for them to be fully realised in Sailrocket 2’s record.

Sailrocket 2 achieved the force alignment with a wing mounted on the leeward hull that was canted over the windward hull by 30°. The force it generated was driving the boat forward and trying to lift the windward hull out of the water.

This force was resisted by a foil under the windward hull. And so that foil was pulling down rather than pushing up. It’s a crucial distinction between Sailrocket 2 and the type of foiling craft used in the America’s Cup or SailGP. In those boats, it’s the leeward hydrofoil that pushes back against the sail force. It also lifts the whole boat up and out of the water.

These two breakthrough ideas – force alignment and super-ventilated foils – along with a ‘no guts, no glory’ attitude, took Larsen and his Sailrocket 2 team over 65 knots, a mark that has been held for almost a decade. But might the time have come for that record to be broken?

“I think we’ve sat on it for long enough and it’s definitely time for it to be challenged,” Larsen says. “There was a time I was quite protective and proud of it, and wanted to sit on that throne for a while. But right now I want to see what other people can do with it and see what their solutions might be. I’ll see if it motivates me enough to get back out there myself!”

New fastest sailboat challengers

There are two major challenges shaping up to take on the Sailrocket team’s record and both should take to the water later this year or early in 2023. One of them, Syroco , has been set up by Alex Caizergues, the first man to travel sail-powered at over 100km/h on water, and twice holder of the outright sailing speed record on his kiteboard. The other, SP80 , has come out of the Swiss engineering school École Polytechnique Fédérale de Lausanne (EPFL).

Kite-powered SP80 challenge uses a super-ventilating surface piercing foil. Photo: SP80

Both are using the principles that Larsen established, and both teams think they won’t just break the record but will smash it. Syroco ’s stated target is 150km/h, a breathtaking 80.99 knots. SP80 is also chasing the 80-knot barrier.

“I actually like where both projects are aiming,” said Larsen. “They’re definitely using the force alignment concept.” Both the SP80 and Syroco teams will use a kite, aligning its aerodynamic force with the hydrodynamic force from a foil. This should allow the generation of an immense drive force on a relatively light structure. They will need all the power they can get to push through the cavitation point.

The SP80 project is also using a super-ventilating, surface piercing foil like Sailrocket’s. “Vestas Sailrocket and the work done by Paul Larsen and his team was the main source of inspiration that we used to develop the boat,” said Benoît Gaudiot, one of the three founders of SP80 .

They started throwing around ideas in 2017, building super-ventilated fins for a kiteboard. Gaudiot, an experience kitespeed sailor quickly got it to 41 knots. They were going to need a different approach to beat the record though.

“The body cannot handle the power that is required to reach more than 60 knots,” said Gaudiot.

SP80 co-founders Xavier Lepercq, Mayeul van den Broek and Benoît Gaudiot. Photo: SP80

Another of the founders, Xavier Lepercq, built a simulation tool, and they started developing designs. What they came up with was a trimaran powered by a kite, whose aligned force was balanced by a surface-piercing foil.

Once this was formulated the team quickly grew, with EPFL pledging its support and sponsors coming on board. “In the team, we have six full-time employees and almost 40 students from EPFL,” explained Mayeul van den Broek, the team’s project manager. They tested a prototype on Lake Geneva in 2020 and in June 2021 began construction of the full-size craft at Persico Marine.

The transition to a kite means that the biggest challenge to both teams is control – accurately balancing the aero and hydrodynamic forces. SP80 has tackled it with what they call the ‘power module’. “The idea behind this is to balance the force. The way we designed the boat, the main thing to achieve was stability,” said Gaudiot.

The exact mechanism of the power module is confidential, but it’s visible at the back of the boat in their visualisations and animations. It provides a direct link between the kite and the hydrofoil and appears to ‘trim’ the hydrofoil depending on the force vector coming from the kite. The shape of the foil and the linkage to the power module are key to the flight stability of the craft.

Swiss SP80 team has been testing its prototype on Lake Geneva. Photo: SP80

“It’s fully mechanical and it’s fully adjusting the balance by itself,” said Gaudiot. “The controls will be quite simple for the pilot. There will be no need for me to control the height, the elevation of the boat, just the direction. And the power of the kite.” The kite lines will run to the cockpit and be controlled with the hands, while the direction of the boat will be controlled with the feet.

The SP80 team plan to challenge the record from a base in the south of France early in 2023, and Paul Larsen is looking forward to it. “I think the SP80 is a more practical solution that has made compromises for practicality. And I think I can get my head around that one a bit more. I think SP80 is probably closer to getting results. And I want to see how a kite’s going to go against the [Sailrocket] wing, because historically wings are faster.”

Flight on water

Looking to spoil the Swiss party is Syroco , a French company that comes to the world sailing speed record with gold-plated credentials. Co-founder and CEO Alex Caizergues has already held the record on his kiteboard.

“Since Paul broke the sailing speed record, I knew that we had to change the software and the way to go fast on water. I knew that I had to assemble around me a team of people able to build this kind of craft,” Caizergues recalls.

Caizergues isn’t just an athlete, he’s a business school graduate with an entrepreneurial track record. Syroco was set up in 2019 with four co-founders and support from technology entrepreneurs and venture capitalists.

Artist’s rendering of how the Syroco craft will look in action. Photo: Syroco

They want to do more than just break the record, building a technology business around the attempt. The team has about 15 people working in Marseille with specialists in fluid mechanics, structures, software and data analytics.

“Our l’aile d’eau concept… it’s a little bit like Sailrocket,” said Caizergues. The concept is very simple; a hydrofoil will ‘fly’ underwater, pulled along by a cable that’s connected to a kite flying in the air above it.

Suspended between the two is a capsule containing the pilot Alex Caizergues, and a co-pilot. The aero and hydrodynamic forces oppose each other in an almost perfect representation of the aligned forces concept that powered Sailrocket 2 .

It should have the greatest speed potential because there is nothing extraneous. The capsule is only there because both the aero and hydrodynamic wings must be controlled, and the forces balanced by the pilots (not automated).

The Syroco prototype under test being towed by a RIB. Photo: Syroco

And that’s the tough part, controlling it, particularly keeping the foil in the water. “Nope,” responds Alex, quickly, when I mention this possibility. “The foil never goes out of the water.” The Syroco foil isn’t surface piercing, it runs below the surface, only connected to the capsule and the kite by a cable.

It doesn’t rely on dragging air from the surface to stabilise the cavitation around the foil. Instead, it will rely on the cavitation creating its own stable pocket of water vapour around the foil – this is called super-cavitation. When it occurs the water flows around the bubble of vapour as though it were a solid, significantly enhancing the performance of the foil – as long as the bubble remains stable.

The problem is keeping the bubble intact. Paul Larsen pointed out that the cable gives the air a pathway down to the super-cavitating foil. “How they’re going to stop air sucking down from the surface and rupturing the bubble, that’s the real trick. It’s a very dynamic problem to solve. It’ll be interesting to see how well their simulations live up to the reality of what they’re about to strap themselves into…”

The control mechanisms for the final craft are still being worked on, but they have flown a prototype, towed by a RIB rigged with a 5m-high mast that simulated the force from the kite. The team hopes to commit to a final design with construction starting in the spring.

Human element

And then of course, there will be the matter of executing the plan on the day. “If you’ve done your maths, you’ve done your engineering, you’ve been thorough, that gives you confidence when you stand up on top of that course on one of those big days and you’re not exactly sure what’s about to happen,” recalls Larsen.

Kiteboarder and businessman Alex Caizergues leads the Syroco project. Photo: Syroco

“You know it’s probably just slightly above your top wind range but all the cameras are rolling and the drones are in the air and everyone’s waiting with their stopwatches. That gives you the confidence to say: ‘Yeah, I’m going to go and wring its neck.’”

“Any crashes I had [and there were several] usually all the systems I had in place [for safety] were still completely locked on among all the wreckage. You’d go and flick off that lever you were going to use to control something – because by the time you’ve realised what’s happening, it’s happened.”

“If we go again with Sailrocket, then safety will feature bigger. I wouldn’t get in that boat and go that speed again. We got away with it because we had to.”

“Safety is really important for us,” agrees Benoît Gaudiot. They have built a kevlar cockpit for protection, installed a six-point harness and an F1-inspired seat. Gaudiot will wear a helmet with oxygen that will switch on if the helmet detects water in contact with its mask. “I would be able to stay in the water for a few minutes to have a diver come and open it.”

“The critical point on the boat is the hydrofoil. If the hydrofoil breaks, the boat…” Van den Broek interjects. “…will take off,” Gaudiot finishes the sentence for him.

Their enthusiasm for the project is infectious, the words tumbling out. And no one wants the boat to take off. One big advantage that they have that Larsen did not, is that they can release the power source. “With a kite it’s a few lines and you can just cut it super-fast,” says Gaudiot. “You can do it by yourself. You can do it from a distance, from the chase boat. You can do it automatically.”

“I think both those guys [Caizergues and Gaudiot], they’ve got the mentality,” said Larsen. “They’re not going to get up there and be scared of what they’re doing or intimidated too much by the craft.”

And what if they do break the record that Paul Larsen and his team have owned for almost a decade?

“We opened the door on a whole new world full of potential. And so there is a part of me that’s curious as to what lies further down that path. We validated the concepts that could get above what people thought were the cavitation limits and the ceilings of speed sailing. We proved you could get beyond that. They can take you to new levels of physics.

“The boat [ Sailrocket 2 ] is sitting there in perfect shape. It was made to last forever… we could rig that thing up and do 65 knots in a week or two.” And if his record goes, I wouldn’t put it past him to dust her off and do just that.

If you enjoyed this….

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How Fast Is A Yacht? 3 Types Checked (With 9 Examples)

Different types of boats require various speeds for maneuvering in various water types and for doing diverse activities.

Depending on what you want to do with your vessel, you might need it to travel at a certain speed.

How Fast Are Yachts?

Yachts differ in speeds depending on the type of boat, with mega-yachts and ocean sport boats being the fastest (at over 30 MPH), cruisers, and deck boats falling second (at an average speed of 23 MPH), then pontoons, and sailboats averaging 10 MPH.

Here’s everything you should know about how fast yachts can go:

Table of Contents

First, How do we Define a “Yacht”?

First, let’s make sure we are talking about the same thing. After all, different types of boats sail at different speeds.

Yachts are boats (sail or power) used for racing, cruising, or just for pleasure.

It is a general term, which makes the question, “What is the average speed of a yacht?” a complicated one to answer.

Yachts can range in length between mini yachts, measured at 23 feet (seven meters), to superyachts, which are at least 78 feet long.

Before covering how fast each type of yacht can travel, here is a quick and dirty list of yachts that this article will cover:

• Has a single deck above the hull with below-deck living quarters. They are normally sleek and sporty.
• Control station, seating, and lounge space.
• It is a large, recreational, and motor-powered boat with multiple decks and a larger interior main deck than a flybridge.
• A yacht that has an enclosed living space and that is longer than 80 feet.
• A yacht that is built and used for fishing. Normally has a large cockpit to store fishing essentials. It is often faster than regular motor-yachts to get to the fishing grounds and back quickly.
• Pontoon boats lie flat on the water, balancing on two (or three) aluminum tubes, instead of having a V-shaped hull like deck boats. This makes them more stable for entertaining large groups of people.
• Primarily uses sails for propulsion instead of a motor (though most have a motor for back-up or to assist with the sails). Most are used for sport, but there are quite a few leisure sailing boat clubs and organizations these days.

The yachts that fall into categories 1 – 6 are motorized but are all smaller than superyachts.

For the rest of the article, the term “motorized yachts” or “powerboats” will refer to one of these.

How Fast Does my Yacht Need to be?

The answer to this question depends on what you want to do with your yacht.

If you’re a fisherman that needs to only troll through calm waters, it might be best if your boat travels with a top speed of around 15 MPH.

But if you’re looking to hit the open waters and speed around with the wind in your hair, you might want something a bit faster than that.

While you’re shopping for boats, and considering the top speeds for each type, ask yourself:

• What activities will you be doing on your boat?
• What sort of waters will I be traveling on?
• What activities will I be doing, which will utilize its top speed?

How Does the Speed of a Boat Affect its Fuel Consumption?

This depends on the type of boat you use. For ease of reference, the Formula 240 Bowrider speedboat (a 24-foot motorboat) is a good example of an average boat.

When cruising at 7 MPH, it consumes approximately three gallons an hour. When you double the speed, it consumes double the fuel (seven gallons an hour at 15 MPH). At 30 MPH, it will use about 11 gallons.

A general rule of thumb is that mid-range speed will offer the best fuel efficiency.

There is no need to merely putter around the water to save money.

How Fast Should I Go on a Yacht?

Unfortunately, there aren’t any speed limit signs out in the open water. Because of that, sailors and boaters have to calculate the speed limit depending on at least three different factors: the time of day, the type of boat, and the type of waterway.

The speed limit for boats is rarely a specific numerical figure. Instead, look for safety concerns, warning signs (like “No Wake Zones”), and rules often posted on the docks.

Watch out for “No Wake Zones,” which can cost a hefty fine if you are caught in violation and can be dangerous to people, animals, and property in the area. Most speedboats and other motorboats can cause a wake in as little as 5 MPH.

If you are close to a river, shore, or populated areas, you have to tread on the side of caution. However, once you are out in open water (like the ocean or a large lake with no one around), you can test out your boat’s top speed.

Make certain that you can:

• See an open pathway of water.
• See no obstacles (people, vehicles, animals, jetsam, or debris)
• Have observed the rules posted at the dock or pier

What are the Top 10 Fastest Yachts on the Market Today?

This list will consist of a variety of motorized yachts, powerboats, and superyachts.

Superyachts are so big; they need a more powerful engine.

For example, the Astro by Baia Yachts uses triple 2,430hp MTU engines and can put out 7 290 hp at its max.

It can go about 57 MPH or 50 knots! And that’s not even fast enough for our top ten list!

10) “The Chato” (built by Baglietto)

The Chato is an 84.61-foot yacht with accommodations for up to six people.

It is an all-aluminum speed demon with two MTU diesel engines, which propel it forward at a whopping 65.59 mph.

9) “Ermis 2 ” (by McMullen & Wing)

The Ermis is a 123.23-foot yacht made of carbon-fiber to make it both light and sleek.

The triple waterjets (MTU 16V 4000 M90 series) push it forward with 11,000 hp, making it fly across the water at a top speed of 63.29 mph.

8) “Black Bullet” (by Otam)

The Black Bullet is an 83.7-foot yacht, is the fastest yacht in the Otam 80 series.

It can accommodate two crew and six guests and moves quickly with four diesel engines.

How quick? 66.7 mph quick.

7) “Oci Ciornie” (by Palmer Johnson)

The Oci Ciornie is an 82-foot yacht that uses a 4,600 horsepower AVCO Lycoming gas turbines, an Arneson surface drives, and twin 1,800 horsepower MTU 16V 2000 M90 engines to propel it forward to 69 mph.

Vroom, vroom.

6) “The Brave Challenger” (by Vosper)

This yacht tops out at 69 mph because of her three gas turbine engines. Together, they generate about 13,620 horsepower. In addition to that, she also has two conventional engines to help her move around the water a little easier when she needs to cruise at a slower speed.

Originally named Mercury, she was built for Stavros Niarchos, a Greek shipping tycoon.

5) “Kereon” (the second boat on our list by AB Yachts)

The Kereon is an 88.6-foot yacht that can top out at 71 mph because of its three diesel engines. She has three 2,250 horsepower CRM diesel engines that were designed by Angelo Arnaboldi, a naval architect.

The Kereon can accommodate six guests in three cabins. She also has a massive fuel tank, which can hold 3170 gallons of fuel. That means she can go approximately 900 nautical miles on one tank of fuel.

4) “Gentry Eagle” (by Vosper Thornycroft)

The Gentry Eagle is a 111.88-foot yacht built for and by Tom Gentry (who worked with Vosper Thornycroft). If his name sounds familiar to you, it’s probably because he set almost every powerboat speed record today. He won the Blue Riband (the award for the fastest passage across the Atlantic) with a record time of 62 hours and seven minutes. The Gentry Eagle beat Richard Branson’s record by 23%.

Talk about fast.

It tops out at 73.64 mph.

3) “Galeocerdo” (by Rodriquez)

The Galeocerdo is a 118.1-foot yacht powered by three Vericor TF50 gas turbines (which drive three Rolls-Royce Kamewa water jets).

The Galeocerdo tops out at 74 mph.

2) “The World Is Not Enough” (by Millenium Super Yachts)

This yacht is a 138.45-foot yacht that can accommodate 10 guests and can go 77.1 mph.

It is propelled by two Lycoming gas turbines and two Paxman diesel engines.

1) “Foners” (by Izar)

The Foners is a 136.15-foot yacht made specifically for King Juan Carlos of Spain’s royal yacht. It was also built for speed with two 1,280 horsepower MAN engines.

But that’s not all, and it also has three Rolls Royce 6,700 horsepower gas turbines that drive three Kamewa water jets.

How fast does it go? It tops out at 80.5 mph!

What’s the Fastest Motorized Yacht in the World?

The record for the fastest boat was set at 317.6 MPH .

Ken Warby was using a speedboat (powered by a jet engine instead of a regular boat motor) called the “Spirit of Australia.”

This was not included on the fastest yacht list because of its unique circumstances.

Final Thoughts:

Choosing the right yacht for you and your needs is a big decision. Make sure you know what you will do with your boat before you buy a boat strictly built for speed.

The bragging rights in owning a boat that can go 80 mph on the water is great.

But if you are only going to use it for trolling or fishing, it would be a waste on your pocketbook and for the boat.

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Yachting Monthly

• Digital edition

Busting the hull speed myth

• julianwolfram
• December 13, 2021

Waterline length is not the defining factor in maximum boat speed that we all think it is. Julian Wolfram busts the hull speed myth

Modern hull forms, like this Jeanneau SO440, use chines to create volume forward while keeping a narrow entrance at the waterline

Every sailor is delighted when the breeze picks up and the boat really starts to get going with a bone in her teeth.

Julian Wolfram is a physicist, naval architect, former professor of ocean engineering at Heriot-Watt in Edinburgh and a Yachtmaster Offshore who has cruised and raced for 45 years

The crew will want to know how fast she will go and perhaps surreptitiously race her against any similar sized boat in the vicinity.

Speculation may start about what allows one boat to go faster than another – is it the hull shape or the sails?

It is easy to spot good, well-trimmed sails but what about the hull ?

The important part is not visible below the water surface. However there is one key indicator that is often very apparent – the waves generated by the sailing yacht.

When a yacht picks up speed the wave pattern around it grows and the greater the speed the bigger the waves .

The energy in these waves is proportional to the square of their height – double the height and the energy goes up by a factor of four.

This energy comes from the wind , via the sails and rig , making the hull push water out of the way.

If less of this wind energy was wasted in producing waves the yacht would go faster.

When a typical displacement monohull reaches a speed-to-length ratio of around 1.1 to 1.2 (speed in knots divided by the square root of the waterline in feet) up to half the wind energy driving it is usually wasted in generating waves.

The hull speed myth: Half angle of entrance

So how can we tell if a yacht will sail efficiently, or have high wave resistance and waste a lot of energy generating waves?

The answer starts back in the 19th century with the Australian J H Michell.

In 1898 he wrote one of the most important papers in the history of naval architecture in which he developed a formula for calculating wave resistance of ships.

Light displacement cruising boat: The bow of this Feeling 44 is finer than older cruising boats

This showed that wave resistance depended critically on the angle of the waterlines to the centreline of the ship – the half angle of entrance.

The smaller the angle the smaller the height of the waves generated and the lower the wave-making drag.

A knife blade can slice through water with minimal disturbance – drag the knife’s handle through and you generate waves.

The big hull speed myth

For a displacement hull the so-called ‘hull speed’ occurs when the waves it generates are the same length as the hull.

This occurs when the speed-length ratio is 1.34.

It is claimed that hulls cannot go significantly faster than this without planing. It is called ‘the displacement trap’ but is a myth.

Heavy displacement cruising boat: An older design has a bow that is several degrees wider

As an example, consider a 25ft (7.6m) boat that goes at 10 knots in flat water.

This is a speed-length ratio of two. That is the average speed over 2,000m for a single sculls rower in a world record time.

The reason for this high speed is a half angle of entrance of less than 5º. Hobie Cats, Darts and many other catamarans have similarly low angles of entrance and reach even higher speed-length ratios with their V-shaped displacement hulls.

These hulls also have almost equally fine sterns, which is also critically important to their low wave resistance.

The monohull problem

Now a monohull sailing yacht needs reasonable beam to achieve stability and, unless waterline length is particularly long, the half angle of entrance will inevitably be much larger than those on rowing skulls and multihulls .

In his 1966 Sailing Yacht Design Douglas Phillips-Birt suggests values of 15º to 30º for cruising yachts.

Many older cruising yachts with long overhangs and short waterline lengths, for their overall length, have values around the top of this range.

Busting the hull speed myth: A Thames barge is a similar length and beam to a J-Class, but its bluff bow, built for volume, makes it much slower. Credit: Alamy Stock Photo

Newer sailing yachts, with plumb bows, have somewhat smaller half angles and a modern 12m-long fast cruiser may have a value around 20º and a racing yacht 17º or 18º.

Size matters here as, to achieve stability, a little yacht is likely to have a bigger half angle than a large one, such as the German Frers-designed 42m (138ft), Rebecca which has a half angle of entrance of under 13º.

Rebecca also has a fine, elegant stern which helps minimise the stern wave – I’ll come back to sterns and stern waves.

Interestingly the half angle of entrance is not mentioned in the otherwise excellent 2014 Principles of Yacht Design by Larsson et al, although it is currently used as one of the parameters in the preliminary estimation of wave resistance for ships.

While it is still particularly applicable to very slender hulls, naval architects are not generally familiar with Michell’s work.

His formula for wave resistance involves quadruple integrals of complex functions.

German-Frers’ designed Rebecca has a half angle of entrance of just 18°. Credit: Cory Silken

These are not ‘meat and drink’ for your average naval architect, and only a few mathematically inclined academics have much interest in theoretical wave resistance.

Michell’s work is rarely, if ever, covered in naval architecture courses now.

Nowadays the emphasis is much more on numerical methods, high-speed computers and computational fluid mechanics (CFD) using the so called Navier-Stokes equations.

Examining these equations, which apply to any fluid situation, does not give any insights into wave resistance, albeit they can model wave resistance very well when used in the piecewise manner of CFD.

It is very easy to measure the half angle of entrance at the design waterline when a yacht is out of the water.

Take a photograph directly upwards from the ground under the centreline at the bow.

Busting the hull speed myth: Multihulls achieve high speeds due to fine hulls, light displacement and ample stability. Credit: Joe McCarthy/Yachting Monthly

Now blow this up on a computer screen, or print it off at a large scale, and measure the angle with a protractor.

Alternatively, if you have a properly scaled accommodation plan drawn for a level close to the design waterline this will yield a reasonable approximation of the half angle of entrance.

Unfortunately there is not a simple relationship between the fineness of the bow and the wave drag.

But, all other things being equal, the smaller the half angle the better.

It is easy to measure and is a useful parameter to know when comparing yachts.

Stern shape and hull speed

The half angle of entrance cannot be taken alone as a measure of wave drag, and the fairness of the hull and in particular the run aft is also critical.

Just as the half angle of entrance dictates the height of the bow wave, so the fineness of the stern is a key influence on the height of the stern wave.

Consider the water flowing around both sides of the hull and meeting at the stern.

Modern race boats, like Pip Hare ‘s IMOCA 60, combine a fine angle of entrance with wide, flat hulls for maximum form stability and planing ability. Credit: Richard Langdon

If these streams meet at a large angle the water will pile up into a high stern wave.

On the other hand if they meet at a shallow angle there will be less piling up. A fine stern can maintain a streamline flow of water.

However if the sides of the hull meet at the stern at a large angle then the streamline flow will tend to separate from the hull, leaving a wide wake full of drag-inducing eddies.

Continues below…

How hull shape affects comfort at sea

Understanding how your hull shape responds to waves will keep you and your crew safe and comfortable in a blow,…

Boat handling: How to use your yacht’s hull shape to your advantage

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Sailing in waves: top tips to keep you safe at speed

Sailing in waves can make for a jarring, juddering experience and long, uncomfortable passages and at worst, a dangerous, boat-rolling…

How to cope with gusts and squalls

Spikes in wind strength can range from a blustery sail to survival conditions. Dag Pike explains how to predict which…

In many modern designs the hull sides are not far off parallel at the stern and it is then the upward slope of the buttock lines that are critical and, again, the shallower the slope the better from a hull drag perspective.

The slope of the buttocks can easily be measured if the lines plan is available and a good indication can be obtained from a profile drawing or a photo taken beam on with the boat out of the water.

Drawing a chalk line parallel to the centreline and half a metre out from it will provide a buttock line that can be checked visually for fairness when the boat is viewed from abeam.

A rowing scull easily exceeds its theoretical max hull speed. Credit: Alamy Stock Photo

Again, the smaller the angle the better – provided the transom is clear of the water.

An angle of more than 17º will lead to separated flow and eddy making. This also happens if the transom is immersed.

The greater the immersion the greater the drag, so weight in stern lockers on modern boats can be critical.

Modern hull design

The modern wedge shape attempts to resolve the conflicting demands of a small angle of entrance, good stability and a fine stern.

The plumb bow extends the waterline forward and, with the maximum beam taken well aft, the hull forward can be relatively narrow, providing a low half angle of entrance.

The stern is wide, which helps achieve good stability, but at the same time the buttocks rise slowly at a shallow angle to the water surface.

This gives a smooth and gradual change in the hull’s cross section area ensuring the water flow remains attached to the hull and that the stern wave is kept low.

A modern cruising boat gains stability from a wide stern, but needs twin rudders

This wide, flat stern also helps surfing down waves and possibly planing.

Some designs have chines just above the design waterline which increases usable internal volume and gives a little more form stability when heeled.

However, as soon as the chine is immersed there will be separation along the chine edge as water will not flow smoothly around a sharp edge.

It is just not possible to get the chine perfectly aligned with the streamlines of the water flow in all sailing conditions and there will be some extra drag at times.

There are two downsides to the wedge- shaped hull.

Overloading aft will create a large increase in drag

First the boat has to be sailed at a small angle of heel to keep the rudder properly immersed and to avoid broaching. This can be offset to some extent by using twin rudders .

The second is that the weight must be kept relatively low.

This is because a relatively small increase in weight causes a big increase in wetted surface area at the stern and hence in the frictional drag which makes the boat slower, particularly in light airs.

This is the downside of slowing rising buttocks and the reason why dinghy sailors get their weight forward in a light breeze .

Displacement Length Ratios

Traditionally for sailing yachts the displacement-length ratio has been used as a measure of speed potential, partly because it is easy to calculate from the yacht particulars.

It is waterline length (in metres) divided by the cube root of displacement (in cubic metres or tonnes).

A heavy boat, such as the Heard 35, will have a value of about 4 to 4.8.

A more moderate displacement boat, such as the Hallberg Rassy 342 or Dufour 32 Classic, will have a value in the range 5 to about 5.5; whilst a racing boat may a value of up to, and even over, 7.

A heavy displacement cruising boat with a fair run aft is less affected by additional weight

However the displacement length ratio can be misleading as making a hull 20% deeper and 20% narrower will keep the displacement the same but will significantly reduce the half angle of entrance and the wave drag.

It is interesting to note a Thames barge in racing trim has the same length-displacement ratio as a J class yacht, but their speed potential is vastly different.

Finally I should mention the older ‘length-displacement’ ratio, which is quoted in imperial units.

This is calculated by dividing a boat’s displacement in tons (2,240 pounds) by one one-hundredth of the waterline length (in feet) cubed.

Credit: Maxine Heath

It is still used in the USA and should be treated with caution.

The myth that your boat’s speed is only restricted by it waterline length does a disservice to its designers, and does little to help you understand how to get the best from her when the wind picks up.

Have a look at how the boat is loaded, how you sail on the wind, your boat handling and how much canvas you ask her to carry and you may discover more speed than you expect.

The remarkable John Henry Mitchell

Pioneer of wave theory

It’s worth saying a little more about the remarkable John Henry Michell.

He produced a series of ground-breaking papers including one that proved a wave would break when its height reached a seventh of its length.

He was the son of Devon miner who had emigrated to the gold mining area near Melbourne.

He showed such promise that he got a scholarship to Cambridge.

He was later elected a fellow of the Royal Society at the age of 35 – not bad for the son of a Devonshire miner.

His brother George was no slouch either – he invented and patented the thrust bearing that is named after him.

The half angle of entrance became the traditional factor for assessing the fineness of hulls.

It is defined as the angle the designed waterline makes with the centreline at the bow.It varies from less than 5º for very fine hull forms up to 60º or more for a full-form barge.

At higher speeds, modest increases in the half angle can give rise to substantial increases in wave resistance.

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What is the Average Speed of a Sailboat?

When I try to figure out the duration of whatever sailing trip I have in the making, I always need to know this one thing first: the average speed of a sailboat - especially with long journeys. If you have the same problem, this article is for you.

So what's the average speed of a sailboat? Most sailboats cruise at a speed of 4-6 knots (4.5-7 mph), with a top speed of 7 knots (8 mph or 13 km/h). Larger racing yachts can easily reach speeds up to 15 knots (17 mph or 28 km/h), with an average cruising speed between 6-8 knots (7-9 mph). Cruising speeds of over 8 knots are uncommon.

Different types of sailboats reach very different speeds. Of course, it all depends on wind conditions, current, and many other factors. Did you know that the speed of a boat is directly related to its length? The larger the boat, the faster it goes. I'll explain it to you later on, but first, more on average speed.

On this page:

Factors that determine speed, converting and calculating sailing speed, calculating the hull speed of your own boat, exceeding hull speed, amount of nautical miles, related questions.

So let's get a little more into detail on sailboat speed. The most important factor in determining the speed is the hull type. I have two rules of thumb for you. The first is: the less of the boat is under water, the faster it goes.

Here are the average cruising speeds for different hull types:

• Monohull - 6-8 knots
• Catamaran and trimarans - 9-10 knots
• Fastest monohull (world record circumnavigation) - 15.43 knots
• Fastest trimaran (world record circumnavigation) - 27 knots

Monohull - Your average sailboat is a monohull. Nearly all monohulls are displacement hulls. A displacement hull is under water, pushing the water away. This allows the boat to cut through the water more smoothly; this stabilizes the boat. If you want to make it go faster, you would have to raise the entire hull above the water. Later on I'll show you how to calculate the maximum hull speed of your boat.

Catamarans and Trimarans - These are planing hulls, meaning they are on top of the water. They displace less water, which is why they are faster. But a planing hull is less stable than a displacement hull. To compensate, catamarans and trimarans have two or three hulls, which makes them extremely buoyant. Since this is not your average sailboat I'll leave them out of this article.

The second factor is the length of the boat. It's the second rule of thumb: the longer the boat, the faster it goes. Each sailboat has a maximum hull speed, which it can't exceed (in theory). The hull speed is determined by the length of the boat.

Here are the maximum hull speeds for different monohull lengths:

Please note: the maximum hull speed isn't the average sailing speed. It's the upper limit (in theory - read on to learn more).

The third and perhaps most obvious factor of course is wind direction and speed. If you plan a large voyage, for example, an ocean passage, make sure to check the dominant wind and direction for your time of year. You want to make sure to have as much downwind as you can get, and a favorable current as well. This is why most sailors choose to go eastward instead of westward when sailing the world.

If you want to know why going eastward is smart, I encourage you to read my previous article on sailing around the world here .

How to calculate necessary sailing speed

So imagine you need to get to dock in time. It's 50 miles away. You need to arrive at 2100 hours. It's currently 1500 hours. Would be handy to know at what speed you need to sail to make it in time.

The formula is simple:

nautical miles / time = average speed necessary

2100 - 1500 = 360 minutes 360 / 60 = 6 hours Your average speed should be: 50 NM / 6 = 8.3 knots

Converting knots to mph and km/h

To convert knots to mph or km/h, simply multiply the knots by the ratio below.

1 knot = 1.151 mph 1 knot = 1.852 km/h

Great, we have a good general idea of what to expect from our trustworthy vessels. If you want to go deeper, you can try to calculate the maximum hull speed of your own boat. Calculating the maximum speed is actually very simple. Now is the time to get out your calculator.

You calculate the maximum hull speed (HS) by taking the length in feet (lwl), get the square root, and multiplying it by 1.34.

HS = √ lwl * 1.34 HS = Hull Speed lwl = length at waterline

So a 80 feet boat has a maximum hull speed of:

√ 80 * 1.34 = 12 knots

A displacement hull has a maximum hull speed. Hull speed is a theoretical speed that tells us what the maximum efficient speed is. Everything above that speed costs a lot more energy. If you power your boat by engine, you can exceed the speed by pushing the hull over your own bow wave (this requires a lot of horsepowers though, and it isn't good for your engine).

If you're sailing instead, you can exceed your hull speed with the help of the weather. Let's call these surfing conditions (sounds good). This might happen to you when you're sailing downwind and the current pushes you forward simultaneously. This helps you to overtake your own bow wave. If this happens, the wavelength gets longer than the hull length: the water can't get out of the way fast enough. As a result, the boat starts to plane, increasing water resistance at the front. Congratulations: you're surfing on your own bow wave.

The increase in speed won't be mind blowing however (about 1 knot). The truth is: a displacement hull is bound to its speed. It just costs to much energy to propel it through the water. It's made to cut, not steamroll the water.

Sailboats don't travel lightning fast, but they do travel 24/7. Because of this, they can cover quite a bit of distance. What distance are we actually able to cover with conservative speeds?

The average sailboat covers a distance of roughly 100 nautical miles (NM) , at a speed of around 4.5 knots. This equals 115 miles or 185 km.

1 NM is 1.852 km or 1.151 mile

You can calculate the distance per day by simply multiplying the speed in knots by 24 hours:

NM = knots * 24

Most sailboats cover anywhere between 100-180 NM per day. This means that a fast sailboat in ideal conditions can cover more than 200 miles. Impressive. However, anything over 180 NM is uncommon. We usually only see cruising speeds that high in races.

Here are the distances per day (NM) for different cruising speeds:

How fast can a sailboat go under power? The average speed of a sailboat under power is 4-5 knots (5 mph or 8 km/h). Most sailors switch to engine at sailing speeds below 6 knots, especially when on passage.

How fast do racing sailboats go? Racing sailboats can reach speeds of 30 - 50 knots (35-58 mph or 55-92 km/h). The record is set at 65.45 knots (75 mph or 121 km/h). They can beat wind speed because they have a planing hull instead of a displacement hull, making them a lot faster than average sailboats

Can a sailboat sail faster than the wind? Sailboats with a planing hull (multihulls) can go faster than wind. Displacement hulls (the average sailboat) can't beat the wind, or just slightly in surfing conditions.

Robert Tangney Kenmare Ireland

Just wondering if you could do a similar article on diesel powered boats.I have a Seaward 23 powered with two 1.6 mermaid engines.I normally do around 7_8 knots and was thinking of replacing them for more speed around 10_12 knots.what engines would I need. According to what I have read already I should be getting 10 knots cruising speed with a top speed of 12 knots.This is not the case and her bottom is very clean.Found your article very interesting.

Shawn Buckles

Hi Robert, thanks for your comment. You have quite a bit of power there, nice.

I wouldn’t know for sure what engine size you should get, this article is specifically about sailboats. Also, this is the maximum hull speed - what you could expect under ideal conditions. And that’s never the case - you have to deal with current, wind, and so on. So I’d say it sounds about right.

If by diesel-powered boats you mean a powerboat, I currently don’t write about powerboats. Maybe I will in the future, but I won’t make any promises for now.

Thanks again and good luck with your upgrade!

I’m not sure if you use a different way of calculating time in nautical terms (Not a sailor myself, just curious about sailboats), but in the ‘How to calculate necessary sailing speed’ my math would say there’s 6 hours = 360 minutes from 1500 hours (3 PM) to 2100 hours (9 PM), not 600 minutes = 10 hours. Am I missing something?

Hi Ben L, That’s exactly right, it was a math error on my part. Thanks for pointing it out, I have updated the article.

Catamarans and trimarans are PLANING boats?! How long have you been sailing? Three days? :-)))

Matas Pacevicius

Just wanted to point out a typo. At hull speed of 5NM you travel 120NM and 138miles (not the 115 written) per 24hrs. Thank you for your articles. I’ve been dreaming of circumnavigation for years and am in the process of designing and building my own sailboat for the feat. I would love to build and sail a sailboat on which I could live almost anywhere in the world. I currently reside on the Gulf coast of Florida and am surrounded by beautiful warm waters that beckon me to explore them. Hopefully in the followings 5 years I will be sailing into the Caribbean in my self-built traveling home in the water. I wish to call the oceans home and soon the entire world. I plan to cross the Atlantic from the Caribbean on my first leg around the world. Would you recommend sailing throughout the Mediterranean? Any ideas on how’s to make money along the way?

I’ve worked all my life, struggling. Now 56y.o. staring at becoming a jobless wanderer in the next couple of months, maybe pick up a used boat. I am just really curious how some people have the time and place to design, build, and then sail around. Tell me your secrets…

Benjamin Lindner

Hello Shawn;

You have an error in your table above: 5 Knots = 120 NM BUT DOES NOT EQUAL 115 MILES.

Thank you Ben

Carlos Alberto Molinelli

But WHY is it a maximum speed for displacement boats in quiet waters, responding to this old formula? It is because the speed increases, the water displaced forms waves. At slow speed there are several along the hull. At fast speed there are only two: one at the bow and another an the stern. If the boat tries to go faster, the stern wave would go more farther but the hull would lose sustentation. It better explained with a picture. Look for boats going fast. You will see only two waves.

Robert Flores

Getting close to retirement and want to get a sailboat with some power. Thinking about sailing lakes and coastal. Looking at the macgregor 26M and seaward 26rk. What recommendations do you have ?? Or things to think about. I am one for safety. Best regards Robert

Ronald Ernst van Dijk

Thank you. Very well explained in clear language, including the usual conversions between knots, miles and kilometers. It helps understanding the physics of sailboats and what to expect in terms of speed. I have just completed building an 18 feet wooden gaff rigged yawl (design by François Vivier) for single handed coastal sailing in Malaysia, the country where I live. Your “rule of thumb” about HS = Lwl * 1.34 seems to work well, although I have to further try it out with different wind speeds and sailing on a reach or down wind.

Your website is an ad horror show to the point it is not usable any more. Ads do have their place and purpose, just like food needs salt. But in your case there is more salt then there is food. Moderation is key.

Ara Houston

Hello improvesailing.com owner, You always provide helpful information.

Leave a comment

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Sailing yachts like Mike Lynch's are 'unsinkable bodies', CEO of boat manufacturing firm says

Bayesian superyacht which sank off Italy is an "unsinkable" vessel, Giovanni Costantino, CEO of The Italian Sea Group, said.

By Ashna Hurynag, news correspondent and Eleonora Chiarella, producer

Thursday 22 August 2024 15:27, UK

Vessels like Mike Lynch's stricken superyacht are "unsinkable", according to the chief executive of the firm which makes and sells them.

Giovanni Costantino, CEO of The Italian Sea Group, told Sky News there are no flaws with the design and construction of the Bayesian superyacht which capsized in a storm off the coast of Porticello, Sicily, on Monday.

Five bodies were found by divers on Wednesday - taking the number of confirmed dead to six.

The Italian Sea Group also owns the firm that built British tech tycoon Mr Lynch's Bayesian, and Mr Costantino said the vessels "are the safest in the most absolute sense".

"Being the manufacturer of Perini [boats], I know very well how the boats have always been designed and built," he said.

"And as Perini is a sailing ship... sailing ships are renowned to be the safest ever."

He said their structure and keel made them "unsinkable bodies".

Read more on this story: Why search of superyacht wreck has been so difficult Hero mum 'slept with baby on deck when storm sank yacht'

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Mr Costantino said news of the sinking "put me in a state of sadness on one side and of disbelief on the other".

"This incident sounds like an unbelievable story, both technically and as a fact," he said.

It is understood Italian prosecutors investigating the incident are continuing to hold interviews with the survivors.

On Tuesday they questioned the captain for more than two hours to help reconstruct what happened and provide useful technical details.

Four British inspectors are also in Porticello and have begun a preliminary assessment of events.

It is understood they will look at all relevant aspects of the incident, including the design, stability, and operation of the vessel. They will also examine the effects of the weather conditions experienced.

Keep up with all the latest news from the UK and around the world by following Sky News

Twenty-two people were on board the vessel, 15 of whom were rescued - including Briton Charlotte Golunski and her one-year-old daughter Sofia.

Divers will resume efforts on Thursday morning to bring ashore a body they found earlier. One more person remains missing.

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• Superyacht sinking

NC to review proposed speed rule changes for small boats meant to protect endangered whales

Environmentalists say slowing down vessel speeds, even of small boats, is needed to help protect the north atlantic right whale. fishermen and local officials say it would devastate coastal economies.

Since the federal government's expanded "speed limit" rule for offshore vessels was first proposed, North Carolina boaters and coastal officials have been vocal in their opposition to the idea of small boats being required to slow down to help protect highly endangered North Atlantic right whales.

Now they get their chance to tell state regulators that.

The N.C. Division of Coastal Management (DCM) is reviewing the federal Bureau of Ocean Energy Management’s (BOEM) consistency determination to see if the National Oceanic and Atmospheric Administration’s (NOAA’s) proposed amendments to the North Atlantic Right   Whale Vessel Strike Reduction Rule  is consistent with state coastal regulations.

That evaluation includes reviewing comments from the public.

For more than a decade, NOAA has had seasonal-management areas, or SMAs, to limit the speed of most vessels 65 feet or longer to 10 knots, about 11.5 mph, in areas known to have heavy ship traffic that are also migratory routes or known calving grounds for the right whales. The  North Atlantic Right Whale Consortium , a group of public and private groups dedicated to the conservation and recovery of the right whale, in late October said new data showed the whale's population at 356 individuals, down from an estimated 483 animals as recently as 2010.

Although hunting of the right whales, so named because they swam close to shore and floated when dead, making them easy to kill and drag ashore for processing, has been outlawed for nearly a century, vessel strikes, fishing gear entanglements and the whales' slow reproductive levels remain major threats to the species' survival.

According to NOAA, there are fewer than 70 reproductively active females . 

The existing go-slow zones, which run from November through April, extend about 20 nautical miles, or 23 miles, offshore and include areas around Morehead City and Beaufort and within 23 miles from shore between Wilmington and Brunswick, Georgia While mandatory for larger vessels, the rules are voluntary for those boats under 65 feet.

SHARING THE WATER: Can endangered right whales and charter fishing boats co-exist off the NC coast?

The proposed new rule would expand the go-slow requirement to boats as small as 35 feet during certain times of the year to help protect the highly endangered whale.

Environmental groups have been pressing the federal government to stop dragging its feet and implement the new rules, which were first proposed several years ago and have been under review at the White House for months. There have been several whales deaths this year, including calves, and whale advocates say time is running out for the species.

"North Atlantic right whales are hovering on the brink of extinction, and the last thing they need is more delay in reducing vessel speeds in some of their most important habitat,” said Kristen Monsell, oceans legal director at the Center for Biological Diversity , in a July 2 release. “It’s been abundantly clear for a long time that slowing vessels down saves whales, so it’s frustrating that the Fisheries Service has dragged its feet on such a straightforward solution.

"It’s time to get this done before it’s too late.”

CHOPPY WATERS: Feds delay decision on small boat speed limit rule that could help endangered right whales

But many legislators, marine trade groups and fishing advocates say such a draconian, blanket go-slow rule would devastate the economies of coastal communities that rely on charter boat and recreational fishermen to fill their hotel rooms, shop in their stores, and fill seats in their bars and restaurants − especially during the fall and spring "shoulder" seasons when many other visitors have gone home.

According to a  report  by the American Sportfishing Association released in May 2022, the recreational fishing industry in North Carolina supports 455,000 jobs and generates $152 in economic impact for every pound of fish landed.

The N.C. Wildlife Resources Commission said there were 345,000 registered boats in North Carolina as of the end of 2023. Of those, nearly 13,500 boats were 26 feet long or bigger.

Public comments on the federal government's proposed go-slow rule can be made and submitted during a meeting at 5:30 p.m., July 23, at the Crystal Coast Civic Center in Morehead City.

The public also can submit written comments to Coastal Management, with the window for submissions closing on July 31. Comments can be mailed to Daniel Govoni, Federal Consistency Coordinator, 400 Commerce Ave., Morehead City, NC 28557, or sent by email to  [email protected] .  Please put “North Atlantic Right Whale Vessel Strike Reduction Rule” in the email's subject line.

Reporter Gareth McGrath can be reached at [email protected] or @GarethMcGrathSN on X/Twitter. This story was produced with financial support from the Green South Foundation and the Prentice Foundation. The USA TODAY Network maintains full editorial control of the work.  

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What Is the Average Speed of a Sailboat (Plus Its Top Speed)?

Sailing is a popular hobby and sport enjoyed by many enthusiasts around the world. The beauty of sailing lies in the challenge of mastering the wind and currents to move a boat forward. One of the fascinating aspects of sailing is its speed. Sailboats can move at varying speeds, depending on several factors. In this article, we will dive into the average and top speeds of sailboats and explore the techniques and strategies to increase sailboat speed.

Quick Facts

Understanding Sailboat Speeds

Before delving into the average and top speeds of sailboats, you need to understand the dynamics of sailboat speeds. Sailboat speeds can be determined by the points of sail, wind direction, and boat design. Points of sail refer to the various angles at which a boat can sail in relation to the wind. These angles include upwind, close-hauled, beam reach, broad reach, and downwind (also called a run). Wind direction plays a crucial role in determining sailboat speed. A tailwind is usually faster than a headwind. The boat design also determines the speed potential of a sailboat.

When sailing upwind, sailboats move slower because they are fighting against the wind. Close-hauled sailing is the point of sail where the boat is sailing as close to the wind as possible. It is the slowest point of sail, as the boat is sailing against the wind. Beam reach sailing is when the boat is sailing perpendicular to the wind. It is faster than close-hauled sailing but slower than broad reach sailing. Broad reach sailing is when the boat is sailing with the wind behind it. It is faster than beam reach sailing but slower than downwind sailing. Downwind sailing is when the boat is sailing with the wind directly behind it. It is the fastest point of sail, as the boat is moving with the wind.

Factors Affecting Sailboat Speed

Several factors influence the speed of sailboats. Wind speed is the most significant factor affecting sailboat speed. The bigger the sails, the more power a sailboat has to move faster. Sail area also plays a crucial role in determining sailboat speed. A larger sail area means more power to move the boat. Boat size and weight also come into play, as larger boats require more power to move at faster speeds. Water friction is another critical factor that affects speed. Friction between the hull and the water can slow down a sailboat, but optimized boat design can minimize this effect.

Boat design is essential in determining sailboat speed. The boat’s hull shape, keel design, and rigging all play a role in how fast the boat can sail. The hull shape affects how the boat moves through the water, and a streamlined shape can reduce water resistance and increase speed. The keel design affects the boat’s stability and maneuverability, which can affect speed. Rigging, including the mast and sails, also plays a crucial role in sailboat speed. A well-designed rig can help the boat capture more wind and move faster.

Measuring Sailboat Speed

There are various ways to measure sailboat speed. The most common method is the use of a GPS or handheld speedometer. GPS offers accurate speed readings, while handheld speedometers are affordable and provide basic speed readings. In sailboat racing, measurements are done using speed logs attached to the boat’s hull or through timed performance over a specific distance. Sailboat speed can also be measured using wind instruments, which measure the wind speed and direction and calculate the boat’s speed based on that information.

Sailboat speed is affected by various factors, including wind speed, sail area, boat size and weight, water friction, and boat design. Understanding the points of sail and how wind direction affects sailboat speed is essential in determining how fast a sailboat can go. Measuring sailboat speed can be done using various methods, including GPS, handheld speedometers, speed logs, timed performance, and wind instruments.

Types of Sailboats and Their Average Speeds

Sailboats come in different designs, shapes, and sizes, each with its unique features and capabilities. Whether you are a seasoned sailor or a beginner, choosing the right sailboat type can make all the difference in your sailing experience. Here are some popular sailboat types and their average speeds.

Dinghies are small sailboats primarily used for recreational sailing. These boats are easy to handle and maneuver, making them a popular choice for beginners. Dinghies usually have a single sail, which limits their speed potential. However, their lightweight design allows them to move swiftly through the water. On average, dinghies can move at speeds of 8-15 knots (9-17 mph).

One of the most popular dinghy sailboats is the Laser, which has been an Olympic class boat since 1996. The Laser is a one-design boat, meaning that all boats are built to the same specifications, ensuring fair competition. The Laser is known for its speed and agility, making it a favorite among sailors around the world.

Catamarans are two-hulled sailboats that have a wide beam, making them stable and fast. These sailboats can achieve high speeds and are popular for racing and cruising. Catamarans have a unique design that allows them to sail close to the wind, making them efficient and fast. On average, catamarans can move at speeds of 15-25 knots (17-29 mph).

The Hobie Cat is one of the most popular catamarans in the world. The Hobie Cat is a small, beach-launched catamaran that is perfect for recreational sailing. The boat’s lightweight design allows it to move quickly through the water, and its unique trampoline design makes it comfortable to sail.

Monohulls are the most common sailboat type. These boats have a single hull and can range from small recreational boats to large racing sailboats. Monohulls are versatile boats that can be used for cruising, racing, and day sailing. The average speed range of monohulls is 5-20 knots (6-23 mph).

The J/Boat is a popular monohull sailboat that is known for its speed and performance. The J/Boat is a racing sailboat that has won numerous regattas and championships around the world. The boat’s lightweight design and high-tech features make it a favorite among competitive sailors.

Cruising Sailboats

Cruising boats are designed for comfort and leisurely sailing. They are usually larger and heavier than other sailboat types and can accommodate large crews. Cruising sailboats are perfect for long-distance sailing and exploring new destinations. The average speed range of cruising sailboats is 5-15 knots (6-17 mph).

The Beneteau Oceanis is a popular cruising sailboat that is known for its comfort and luxury. The Oceanis has a spacious interior and can accommodate large crews, making it perfect for extended sailing trips. The boat’s sturdy design and reliable performance make it a favorite among cruising sailors.

Racing Sailboats

Racing sailboats are designed with performance in mind. These boats are usually lightweight and have a larger sail area than recreational sailboats, allowing them to reach high speeds. Racing sailboats are perfect for competitive sailors who want to push their limits and test their skills. The average speed range of racing sailboats is 20-30 knots (23-35 mph).

The Melges 24 is a popular racing sailboat that is known for its speed and agility. The Melges 24 is a one-design boat that is used in numerous regattas and championships around the world. The boat’s lightweight design and high-tech features make it a favorite among competitive sailors.

How to Increase Your Sailboat’s Speed

There is nothing quite like the feeling of sailing at high speeds, with the wind in your hair and the sun on your face. However, achieving maximum speed on a sailboat requires more than just a favorable wind. In this article, we will explore some tips and techniques to help you increase your sailboat’s speed and performance.

Optimizing Sail Trim

Sail trim refers to the setting of the sails in the most efficient way possible to harness the wind’s power and produce maximum speed. Proper sail trim can also improve the boat’s stability and balance. Optimizing sail trim involves adjusting the sails to the correct shape, angle, and tension.

One way to achieve the correct sail trim is to use telltales, which are small pieces of yarn or ribbon attached to the sail. By observing the telltales, you can adjust the sail’s position to achieve the optimal angle and tension. It is also essential to adjust the sails according to the wind conditions. For example, in light winds, the sails should be fuller, while in strong winds, the sails should be flatter.

Balancing the Boat

A balanced boat helps the sailboat move smoothly and efficiently through the water. Balancing the boat involves shifting the crew to counterbalance the forces applied on the sailboat, such as wind gusts and waves. Proper weight positioning can reduce drag and maximize boat performance.

When sailing upwind, it is essential to keep the weight forward to prevent the boat from heeling too much. Conversely, when sailing downwind, it is best to keep the weight aft to prevent the bow from digging into the water. Additionally, it is crucial to keep the weight evenly distributed from side to side to maintain the boat’s balance.

Reducing Drag

Drag is the resistance a sailboat encounters as it moves through the water. Reducing drag can increase speed potential. Techniques to reduce drag include using smooth hull coatings, eliminating unnecessary weight, and keeping the boat clean and free of barnacles and other marine growth.

Another way to reduce drag is to minimize the amount of exposed surface area on the boat. This can be achieved by using a smaller headsail or reefing the mainsail in heavy winds. It is also important to keep the sails properly trimmed, as a poorly trimmed sail can create unnecessary drag.

Proper Maintenance

A well-maintained sailboat operates at its full potential and can achieve higher speeds. Proper maintenance involves regular cleaning, lubrication, and replacement of worn-out parts. It is also essential to keep the sails and rigging in good condition.

Inspect the sails regularly for any signs of wear and tear, such as frayed edges or holes. Replace any damaged sails promptly. Similarly, inspect the rigging for any signs of corrosion or damage. Lubricate the moving parts regularly to ensure smooth operation. Finally, keep the boat clean and free of debris to reduce drag and improve performance.

By following these tips and techniques, you can increase your sailboat’s speed and performance, and enjoy the thrill of sailing to the fullest.

Sailboat Top Speeds

Speed records for different sailboat types.

Sailboats have achieved incredible speeds over the years, with some breaking speed records. The Sailrocket 2 holds the world speed record for sailing at 68 mph. The Vestas Sailrocket 2 is a hydrofoil sailboat that uses advanced technologies to slice through the water at high speeds.

Another sailboat that has broken speed records is the Macquarie Innovation. This sailboat was designed to reach high speeds and broke the world sailing speed record in 2009 by reaching a speed of 50.7 knots (about 58 mph). The boat was built with high-tech materials and was designed to reduce drag and increase speed.

Factors Affecting Top Speed

Top speed is the fastest that a sailboat can travel and is influenced by several factors. These factors include wind speed, boat size and weight, sail area, and water conditions. In most cases, the larger the sail area, the faster the boat can go, and wind direction plays an essential role in achieving top speeds.

The weight of the boat can also affect its top speed. A lighter boat can move faster through the water and is easier to maneuver. Sailboats with hydrofoils, like the Sailrocket 2, can lift out of the water, reducing drag and allowing for faster speeds.

Pushing Your Sailboat to Its Limits

Pushing your sailboat to its limits requires experience, knowledge, and skill. It involves maximizing boat speed in various wind and water conditions while staying safe and in control. Before attempting to push your boat to its highest speeds, ensure that your boat is in top shape, and you have all the necessary safety equipment.

It’s also important to understand the wind and water conditions you’ll be sailing in. Wind direction and strength can greatly affect your boat’s speed, and understanding how to use the wind to your advantage is essential for achieving top speeds. Additionally, water conditions can affect your boat’s speed, with choppy water slowing you down and calm water allowing for faster speeds.

Finally, it’s important to practice and build up your skills before attempting to push your sailboat to its limits. Start by sailing in calmer waters and gradually work your way up to more challenging conditions. With practice and experience, you’ll be able to maximize your boat’s speed and push it to its highest limits.

Sailboat speed is influenced by several factors, including wind speed, sail area, boat size and weight, and water friction. The average speed range for different sailboat types varies and depends on boat design. You can increase your sailboat speed by optimizing sail trim, balancing the boat, reducing drag, and proper maintenance. Top speeds are influenced by wind conditions, sail area, boat size and weight, and water conditions. Pushing your sailboat to its limit requires experience, knowledge, and skill, and always remember to prioritize safety.

Sailboat FAQS

How fast can a 40 ft sailboat go.

A 40-foot sailboat can typically go around 8-12 knots (9-14 mph), depending on wind conditions and the specific design and condition of the sailboat. Speed can be influenced by factors such as hull design, sail area, and weight.

How fast can a 100 foot sailboat go?

A 100-foot sailboat can reach speeds of around 12-16 knots (14-18 mph), depending on factors like the sail area, hull design, and the wind conditions. However, larger sailboats often prioritize comfort and stability over speed, so they might not be as fast as some smaller, performance-oriented sailboats.

How far can a sailboat travel in a day?

This largely depends on the speed of the sailboat and the conditions in which it is sailing. However, if a sailboat maintains an average speed of 6 knots (around 7 mph), it can travel approximately 144 nautical miles in a day of 24 hours. Please note this is a rough estimation and actual mileage can vary significantly based on numerous factors.

What is a comfortable sailing speed?

A comfortable sailing speed is subjective and can vary depending on the type of sailboat and the conditions. However, for many cruising sailboats, a speed of 5-8 knots (6-9 mph) can be comfortable. This speed allows for a good balance of progress and safety, while keeping the ride relatively smooth and the boat easy to control.

Can one person sail a 35-foot sailboat?

Yes, a 35-foot sailboat can be handled by a single person, given that they have sufficient sailing experience and the boat is rigged for single-handed sailing. However, it’s crucial to note that single-handed sailing involves a higher level of risk and requires extensive experience and skills. It’s also important to have an autopilot system or self-steering gear on board to aid in maneuvering and navigation.

Can one person sail a 50-foot sailboat?

Sailing a 50-foot sailboat single-handed is possible, but it is considerably more challenging and requires a high level of experience and expertise. The size and weight of the boat can make maneuvers like docking and anchoring quite difficult for a single person. Additionally, the boat should be well-equipped with an autopilot system and other equipment designed for single-handed sailing. It’s always recommended to have additional crew members on larger boats for safety and assistance.

John is an experienced journalist and veteran boater. He heads up the content team at BoatingBeast and aims to share his many years experience of the marine world with our readers.

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In Maine, a Father-Daughter Team Wins a Lobster Boat Race

Jeremy Beal, a boat builder and lobsterman, had a simple strategy: “Point it and punch it!” His 14-year-old daughter took it from there.

By Steven Kurutz

Reporting from Long Island, Maine.

Dozens of boats zipped across Casco Bay during the Maine Lobster Boat Races on Saturday. Only one had a purple bottom.

That boat, a 32-footer with a powerful diesel engine, belonged to Jeremy Beal, 45, a large, soft-spoken man who comes from a long line of boat builders and lobstermen.

“See, I grew up right in it,” he said between drags of a cigarette while leaning against the rail of his boat on the evening before the big race.

For decades, Mr. Beal’s father, Wayne Beal, and an uncle, Calvin Beal, have built boats used by commercial fishers up and down the Maine coast. After years spent learning the family trade, Jeremy took over his dad’s business, Wayne Beal’s Boat Shop, in Jonesport, a seaside town more than 200 miles northeast of Portland.

“I bought the boat off my father,” Mr. Beal said. “It was his last power boat. He’s retired out of the boat shop. I won’t sell the boat unless I have to. Just for the fact that it was my dad’s.”

To pay off the boat, Mr. Beal has returned part-time to lobster fishing, something he first started doing at age 6. This summer he has been helped by his 14-year-old daughter, Mariena Beal, who will enter ninth grade at Jonesport-Beals High School next month.

Together, father and daughter have been dropping 250 traps into the Gulf of Maine to catch thousands of the large lobsters prized around the world for their meat. They split whatever money is left after paying for the bait (herring, mostly), fuel and the monthly boat bill.

Mr. Beal said he hoped the experience would teach his daughter both financial responsibility and the family’s way of life on the water. But Mariena didn’t quite get her way when it came to the color of the boat.

“She wanted a pink bottom, but I wouldn’t let that fly,” he said.

The pair hit on purple as a compromise. And Mariena got to name the boat — My Turn, she called it.

When they are not hauling up traps, Mr. Beal and his daughter have been competing on the lobster boat racing circuit, an annual series of summertime competitions along the Maine coast. The events, run by the Maine Lobster Boat Racing Association, are essentially drag races — the fastest boat wins.

“I’ve always been a competitor,” Mr. Beal said.

He summarized his racing strategy: “Point it and punch it!”

Two days before the recent race, Mr. Beal unloaded the buckets of herring he keeps on deck. He lugged out the lobster crates and the 55-gallon plastic drums that store the catch. Finally, he took a scrub brush and washed down the deck with Dawn dish soap.

On Friday morning, after waking early and packing sandwiches for lunch, Mr. Beal charted a scenic southwesterly course from Jonesport. Alone on deck, he took in the sight of the rocky coastline and marine life, including porpoises. His wife and daughters, including Mariena, drove the 200 miles separately in a car.

It took Mr. Beal just under five hours to sail to Long Island, one of Maine’s Casco Bay islands that lie a few miles from Portland. Many of its 230 residents work on boats or own one.

A crowd had gathered for a cookout at the old boathouse on Wharf Street when Mr. Beal moored his vessel. Men and women were eating hamburgers, drinking beer and lining up to buy race merchandise from Lisa Kimball, an islander who co-chairs the race. The proceeds were going toward a scholarship fund for children on the island.

Mr. Beal made the rounds. Several of the partygoers had bought their boats from him or his father. The price of lobsters was solid this year, everyone agreed, though the catch varied from “good” to “horrible,” depending on who you asked.

Adam Kimball, Ms. Kimball’s husband, planned to race the next day. He works on an oil tanker in Alaska, but you don’t need a commercial fishing license to compete — so long as you have a typical lobster boat, which he does.

“It’s a lot of money to spend for not a lot of return,” Mr. Kimball, 46, said with a laugh.

He was referring to the modest prize money, usually a few hundred dollars, and to the way some boat owners invest thousands to gain horsepower and perhaps a knot or two in speed.

“They call it ‘gooning up’ the engine,” Mr. Kimball said. “There are some risks to that. Like you blow it up.”

Mr. Beal spotted one of the modern legends of the lobster boat racing.

“Stevie Johnson,” he said. “Now there’s a real character.”

Mr. Johnson, the proprietor of Johnson’s Boatyard on Long Island, is known for building unusual boats , some with automobiles mounted on the hulls. One of them, the “Vette-Boat,” features a 1984 Corvette on a 28-foot hull. Mr. Johnson has won his share of races on his tricked-out vessels over the years, but their main purpose is “to cause a scene,” he likes to say.

Dressed in a blue Hawaiian-print shirt, blue board shorts and Crocs, and nursing Canadian Club whiskey and ginger ale in a red plastic cup, Mr. Johnson, who is in his 70s, was trailed by a small entourage at the cookout.

It was getting late. Mr. Beal untied his boat and sailed over to Portland, where a friend was letting him dock while in town.

Mariena had missed the cookout — she was at the Maine Mall, the largest shopping plaza in the state, doing some back-to-school shopping with her mother. The next day, she would be at the wheel of My Turn.

“She’s like me,” Mr. Beal said. “She likes to go fast.”

And the Winner Is …

She also likes to shop. Mariena and her family members missed the noonish start time of the races on Saturday because they had gotten stuck in traffic after spending the morning back at the mall.

Mr. Beal stood at the wheel of My Turn, engine idling, listening to an announcer call the first few races over a marine radio.

At quarter to one, Mariena came bounding down the dock and onto the boat. She wore black shorts, a white North Face long-sleeved top and leather sandals. Her toenails were painted purple, matching the color of her nose ring and the bottom of My Turn.

Like her father, Mariena was reserved. Asked what she liked about racing lobster boats, she replied, “Everything.”

She was joined on the boat by her mother, Maria Beal; her boyfriend, Caleb Geel; her older sister, Caitlin Childers; and Caitlin’s boyfriend, Nick Guptill.

Mr. Beal gunned the throttle and sped toward Long Island. By now, dozens of pleasure crafts and lobster boats were on the water. A crowd of spectators stood at the ferry dock.

Mr. Beal pulled up to the large boat where officials kept watch over the day’s races through binoculars. His passengers disembarked, leaving My Turn for the so-called committee boat.

Then Mr. Beal and Mariena motored toward the starting line, which was nearly a mile north. Once they were among the other boats in their race category — the G classification race, for boats from 28 to 35 feet in length with diesel engines — Mariena took the wheel.

The committee boat was like a floating party, with coolers of food and drinks. Jon Johansen, the bearded president of Maine Lobster Racing, and the publisher of Maine Coastal News , which covers the races, used a telephoto lens to call out the action.

On board, Maria Beal told a story.

Well into the time she was pregnant with Mariena, she said, she had done a lot of lobstering with her husband. That meant hauling up heavy traps to the point that she ruptured her placenta. The doctors thought she would lose the baby.

”But I went to bed for two weeks and it healed up,” Maria said. “And that’s why we named her Mariena — it means ‘lover of the sea.’”

It was now time for the G classification race.

The lead boat was a speck on the water. As it came closer, you could make out its purple bottom leaving a white-capped wake and all the other boats behind it.

Mariena had won, easily. The Beal contingent whooped and cheered.

“She doesn’t have much fear,” her mother said. “Never has. She’s been looking for speed since she was born.”

My Turn sidled up to the committee boat. Amy Tierney, a race co-chair, handed over an envelope of prize money. Mariena was $200 richer.

What did she plan to do with her winnings?

She smiled.

Steven Kurutz covers cultural trends, social media and the world of design for The Times. More about Steven Kurutz

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Boat Speed Calculator

Welcome to the Boat Speed Calculator! Have you ever wondered how fast your boat can go or what its maximum speed can be? This calculator is designed to assess the top speed of your boat based on its displacement and power, using a constant factor for different types of boats.

What is boat Speed

Boat speed is defined as how fast a boat can go or what its maximum speed can attain. You may wonder if boat speed is the same as vehicle speed, which is typically the ratio of distance traveled over time, but that is not the case. Boat speed is measured differently.

In the above formula, P represents the power of the boat engine, D represents the water displaced by the boat, and C is a constant factor that varies for different boats. This formula is known as Crouch’s formula.

Formula and Crouch constant

For a boat, the formula S = √(P / D) × C can be used to determine the speed, where:

• S is the speed of the boat.
• P is the power applied to propel the boat.
• D is the drag acting against the boat.
• C is a constant, which in this context is often referred to as the Crouch constant.

In marine engineering, the Crouch constant is used to relate the power and drag to the speed of a boat. This constant varies depending on the hull type, propeller efficiency, and other factors specific to the boat's design and operating conditions.

Determining the Crouch Constant

The Crouch constant C for boats typically has to be determined empirically or taken from established data for similar types of boats. Here is how you can approach determining or using the Crouch constant:

C = S / √(P / D)

Using this method, you can plug in known values of S , P , and D to compute C .

• Reference Values : For certain classes of boats, there might be published values or typical ranges for the Crouch constant. You would need to refer to marine engineering texts, boat design manuals, or empirical studies to find these values.
• Standard Values : For many planing boats, a typical value for the Crouch constant is around 150 to 200 in consistent units (e.g., knots for speed, horsepower for power, and pounds of drag). However, this can vary widely.

Example Calculation

Let's assume we have the following data for a specific boat:

• Speed ( S ) = 20 knots
• Power ( P ) = 300 horsepower
• Drag ( D ) = 500 pounds

First, calculate the ratio P / D :

P / D = 300 hp / 500 lb = 0.6 hp/lb

Next, find √(P / D) :

√(0.6) ≈ 0.775

Now, use the formula to solve for C :

C = S / √(P / D) = 20 knots / 0.775 ≈ 25.8

So, in this example, the Crouch constant C would be approximately 25.8, assuming the units are consistent and appropriate for the formula.

What is Displacement or Drag against the boat (D)

Displacement is the weight of the water that a vessel displaces when it is afloat. It is an indicator of the vessel’s size and volume.

Types of Displacement :

• Lightship Displacement :
• The weight of the vessel without cargo, fuel, or other loads.
• Loaded Displacement : The weight of the vessel with full cargo, fuel, crew, and any other supplies.

Measurement Units : Displacement is typically measured in metric tons (tonnes), kilograms, pounds, or cubic meters (for volume displacement).

Importance : Displacement is crucial for determining a vessel’s stability, buoyancy, and how much cargo or weight it can carry without sinking or floating improperly.

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Measuring Performance

What do the numbers tell us about seaworthiness, stability and speed.

All sailors are performance oriented. It’s only when we delve into the details that differences arise. One-design racers know that their place in the fleet hinges on tactics as well as boat speed. Those racing to Bermuda, Hawaii or even more distant landfalls, discover that a timely finish depends upon boat speed in the fog, in the middle-of-the-night and during light air interludes—not just when everyone is rolling along at hull speed.

A cruiser faces a different quest. Their perspective on performance is shaped by a smaller crew members, more reliance on self-steering gear and a propensity to enjoy the ride rather than shave seconds off each mile. So, when it comes to defining your performance perspective, make sure you and your crew agree on the traffic lane in which you prefer to sail and make sure your boat aids and abets that effort.

Race boat designers are innovators, and when it comes to an empirical approach to yacht design, they and their computers juggle a wide range of variables. Speed under sail isn’t the only frame of reference. At the same time they also have to contend with rating rules meant to penalize what makes a sailboat go fast. The goal is to come up with a design that favors boat speed, safety, sail-handling efficiency and creates a sailboat that’s minimally penalized by the rating rule. At times this “shaped to a rule” approach can lead to some unwanted attributes. In this overview, we will ignore the trend to design to a rating rule and look at the features that make some sailboats much better performers than others.

Our version of performance is more than a singular focus on polar diagrams and boat speed. We agree that good performance needs to be realized in a wide range of wind and sea states. But we also place considerable emphasis on seaworthiness, seakindliness, ease of boat handling and crew comfort. These can be contradictory elements, and which gets most emphasis helps to define the differences among the sailboats being built today.

Boat speed-related features are fairly easy to recognize. For example, most sailors have caught on to the idea that tall rigs, large sail plans and light displacement are more than a subtle promise of speed. Shorter rigs, sprouting from heavy displacement hulls are fine in windy parts of the world. But they don’t deliver much drive in light air. When a yacht broker mentions that, “you don’t need to tuck in a reef until it’s blowing over 25 knots,” take a close look at the rig and the vessels displacement. Then ask yourself if it’s not more likely that delayed sail shortening is really due to a shortfall in sail area? You can also answer the question by working out the sail-area to-displacement ratio following the details below or go online to www.tomdove.com/sailcalc/sailcalc.html . The answer gives you a good idea of the boat’s potential power under sail.

Decades ago, in the heyday of the cruiser/racer, a single design stereotype defined most of the fleet. In those days, the majority of sailboats on Long Island Sound, Tampa Bay or berthed in Marina del Rey slips were white hulled sloops sporting blue mainsail covers. This was an egalitarian era when cruisers raced and racers cruised. The net result was better seamanship. Cruisers could set spinnakers and racers knew how to anchor.  Today, sailboats have become more differentiated.  The fast, agile, nicely fitted out cruiser/race is still around by much less common. The result is even fewer racers are going cruising. Modern race boat deck layouts make anchoring  a gymnastic event and there’s little likelihood that there’s even a properly sized anchor on board. Cruisers are missing out on the seamanship development linked to racing and how it benefits sail handling while cruising.

Yacht design guru Bill Lee, coined the apt phrase “Fast is Fun.” He also recognizes that too fast can be trouble and what defines the latter is often determined by the skill set of the crew. Knowing when and how to shorten sail is a talent every sailor should cultivate. Some put that lesson on hold, and that’s OK as long as they master the art of avoiding challenging situations. This is hard to do and can lead to a lot of anxiety. Plus, it also takes much of the fun out of sailing. It’s better to prepare your boat and her crew to cope with the unexpected. This begins with developing an awareness of the boundary between being reasonably powered up versus being on the edge, about to lose control.  It’s not a situation enumerated by a specific boat speed, wind velocity or angle of heel.  But as one crusty old Maine coast cruiser put it, ”I can’t say exactly where trouble lies, but you’ll know when you get there.” The best solution is knowing how to depower in a hurry and safely cope with reductions in sail area.

Singlehanders, along with most shorthanded crews, really value the uptick in performance they get from the right gear. It improves efficiency in reefing, setting and dousing sails.  Cruisers with an aversion to performance sailing have usually been through too many fire drills.  Their version of how much sail area to set is often based upon bad experiences with less than adequate gear. Today’s sailing hardware and furling systems are rugged and reliable, but they still need to be carefully maintained. The crew must also know how to operate the gear in all kinds of conditions—from a midday thunderstorm to a midnight gale.

What to look for

The next time you go to a local boat show, do a little DIY performance profiling. At most shows, you’re likely to run into a full spectrum of sailboat designs. Start with the speedsters and tally up the go fast features. Sail area leads the list and with it comes lower windage, lighter weight rigging and spars—all have benefitted from better engineering and higher modulus materials.

A GZ curve illustrates righting lever. The high peak represents a boat’s maximum righting arm, which is only a part of the overall stability picture.

An offshore sailboat should have a limit of positive stability (LPS) (also known as the angle of vanishing stability- AVS) of 120 degrees or more. It is this ability to recover from a deep capsize that’s like money in the bank to every offshore passagemaker.  

• The area under the positive portion of the GZ curve should be compared with the area under the negative portion. The higher the ratio between the two, the more seaworthy and less likely a monohull is to capsize and the more likely it will recover from a deep knock down.
• Lowering ballast lowers the CG and increases a vessel’s limit of positive stability. In these examples, three identical 30 footers with the same amount of ballast, but differing keel stub depths, alter their draft and GZ curves. Boat 1 (5’ draft), Boat 2 (6’ draft) and Boat 3 (4’ draft). Note that Boat 3, the shoal draft option, has the lowest LPS and Boat 2, has the deepest draft, highest LPS and will sail to windward better than the other two boats.

A growing concern among many offshore cruisers has been a trend toward increased beam, diminished draft and a reduction in ballast. Sailing a reach makes these design changes less noticeable, but as soon as you harden up, a performance shortfall comes into play. With less ballast and no one perched on the rail, excessive heel necessitates a reef. In many cases, the shallow draft keel is almost completely hidden as the leeward portion of the hull submerges. This causes the sailboat to slide sideways and every beat to windward becomes a lesson in leeway.

The preference for deep draft is one thing that hasn’t changed too much among race boat designers.  Centerboards, dagger boards, drop keels and can’ting keels are also in the mix.  And it’s clear that there’s been a downward trend in displacement that fits into the performance-enhancing puzzle. Today, the “less is more” rule prevails. In the 1980s, a race-winning, IMS 40-footer weighed around 18,000 pounds. Now many 40 footers tip the scale at around 10,000 pounds and carry more sail area than their predecessor. The trend flips, however, when it comes to the price tags and sticker shock. It gets quite expensive to shave weight and add speed due to the need for more esoteric materials and aerospace construction skills. The bottom line is how much is it worth to you to add a few tenths of a knot?

Multihull aficionados continue to assail the logic of lead.  Monohull designers are using less but locating it more strategically at the tip of a high aspect ratio foil. This lowers the CG, increasing the righting moment but greatly adds to the stress focused at the keel to hull junction. Keel failures have become enough of an issue that the ISAF Technical Committee has been looking into the problem and they are favoring recommendations that builders increase the hull laminate thickness in the area around the keel attachment. This is a good example of how performance-enhancing features must be considered in the greater context of overall vessel design and construction. Good performance is desirable, staying afloat is essential.

Stability Examined

Righting moment and buoyancy are forces that work together to resist the heel induced by wind pressure on the sail plan. The more sail area, the greater the heeling moment. Multihulls have very high initial stability that’s derived from their wide beam. Monohulls have less initial stability, so when sailing to windward they soon begin to heel over. However, their “ace in the hole” is a highly appreciated attribute called secondary righting moment. It’s derived from ballast and keel geometry.

Multihulls might have been a side show a few decades ago, but they now hold a mainstream role in the sailboat marketplace. Like cruising monohulls, they range from comfortable houseboat like cruisers to absolute speedsters. The latter features more sail area, lighter displacement and much more clearance between the sea surface and the underside of the bridge deck.

Fixed wing masts, C and T foils and all carbon construction can help to juice up the ride. However, the downside to state-of-the-art, aircraft quality carbon fiber construction, seen aboard $7.8 million Fast Forward Composites Eagle 53, can result in serious sticker shock. But the ride says it all, acceleration with the fixed-wing spar is near instantaneous. Time will tell if it’s all just too radical or a full-scale glimpse of what lies ahead.

Displacement/length ratio

I prefer to preview a sail in a new boat by tallying up the numbers.  For example, the J/99 is a 32’ J/Boats, Inc racer/cruiser with enough Spartan accommodations below to do some fast passage making. She looked like a double-hander’s delight and with an ISO Cat A rating and the following vital signs, the performance potential is clear:

8,900 lbs. displacement

6.5 ft. draft

11.2 ft. beam

137 limit of positive stability

37 percent ballast ratio

170 D/L ratio

24.1 SA/D ratio

The data indicated an excellent performer in a wide range of wind speeds and the boat lived up to expectations.

For decades, naval architects and yacht designers have been putting complex as well as simple equations to good use. We’ll take a look at a few of the latter and see how they can help to put a more definitive label on specific sailboats.

Displacement length ratio is a comparative tool that allows us to group sailboats into five different performance categories.  The ratio itself is a non-dimensional number that defines the relationship between weight and length of a vessel. Most sailboats fall between 100 and 400 on this rating scale. At the low end reside light weight speedsters and at the high end are heavy vessels that need a lot more sail area to attain the performance of vessels toward the lower end of the scale. The D/L ratio is a handy way to empirically make boat-to-boat comparisons.

The equation used in this calculation is based on a vessel weight expressed in long tons (2,240 pounds) and the load waterline length (LWL) measured in feet. Don’t let the math bother you. It can be followed like a recipe and a calculator will insure the accuracy of your arithmetic. D/L = DLT ÷ (0.01 X LWL)3

So, let’s assume we are calculating the D/L ratio of a sailboat with a 32’LWL and 18,000 pounds of displacement:

• Convert displacement (D) in pounds to D in long tons (18,000 ÷ 2,240 = 8.0357)
• Multiply the constant 0.01 times the 32’ LWL (0.01 x 32 = .32)
•  Cube the result (.323 = .0328)
•  Divide displacement (in long tons) by the modified LWL (8.0357 ÷ .0328 = 245)
• The displacement length ratio is 245 , it lies in the upper half of the moderate category, a highly populated portion of the scale and a region representative of many offshore cruising boats. (Ultralight <90, Light 90 – 180, Moderate 180 – 270, Heavy 270 – 360, Ultraheavy > 360)

When looking at D/L ratios, it’s important to know the trim state of the vessel when it was measured. The weight of fuel, water and a cruising payload will affect the trim. Brochures often provide “light trim” statistics, but “half trim” status is used by most designers and presents a more realistic profile.

Whatever the case, make sure that the boats you compare are all in the same state of trim. The lighter the vessel, the more of an impact a sizeable payload will have. Also recognize that sailboats with no overhang and those with long overhangs skew the ratios in opposite directions. Plumb bowed, long LWL vessels earn lower ratios while long overhangs contribute to higher ratios.

Sail Area/displacement ratio

Sail-area/displacement ratio is a performance-linked statistic that defines potential power under sail.  The comparative metrics are vessel displacement and sail area—a sailor’s rendition of an automotive horsepower-to-weight ratio. In this case, sail area is measured in square feet or meters. No attention is given to how efficient or inefficient the hull shape happens to be. In other words, it doesn’t matter if the hull shape looks like the city dock or the underbody of the first to finish in the Newport-to-Bermuda Race. As long as their displacements and working sail area are the same, so will their SA/D ratios. The value of this metric lies in its ability to depict potential power for a given displacement—another useful tool in boat-to-boat evaluations. Solving the equation does involve changing vessel weight into the volume of water it displaces.

Headsail area in the formulae below refers to the working sail area or more specifically (J x I) ÷ 2 = SA (headsail). The mainsail area has become the actual square footage because the large roach (race boats) or the hollow leech (associated with in-mast furling systems) cause simple triangle area calculations to be too inaccurate.

In the following calculation we look at a sailboat that displaces 18,000 pounds and has a working sail area of 750 square feet.

• Convert water volume to weight one cubic foot of salt water = 64 pounds (18,000 ÷ 64 = 281.25)
• Calculate the sail-area displacement using (SA/D = SA sq.ft. ÷ (D cu.ft. ÷ 64)2/3) ( 750 ÷ (281.25)2/3 = 17.44)
• So our SA/D is 17.44, which puts it near the top of good performance. ( <15 under-canvased, 15-18 good performance, 18-20 excellent performance, 20< a handful)

Ballast ratio

Ballast Ratio—is a quick and easy calculation that doesn’t involve long tons or a weight-to-water volume conversion. It’s a simple comparison of weight of ballast to weight of the entire boat calculation, expressed as a percentage. B ratio = (Bwt ÷ Disp) x 100.

Assume an 18,000 pound sailboat has 7,200 pounds of ballast.

B#ratio = (8200 ÷ 18000) x 100 = .40

A 40 percent ballast ratio contributes to a sailboat’s secondary righting moment. How much it contributes,depends on how deep the ballast is placed. The big plus behind a substantial secondary righting moment is that it results in a very small negative portion to the boat’s stability curve. This means that the vessel is much less likely to capsize and quite able to quickly recover from a deep knock down.

Many naval architects consider a 120°-130° limit of positive (LPS) a minimum for smaller to mid-sized offshore  cruising sailboats. This can be accomplished with a high ballast ratio and less draft or a lower ballast ratio and deeper draft. The latter often entails a fin and bulb or anvil shape at the very tip of the keel.

These numbers aren’t SAT scores and higher isn’t better. They should be thought of as a sequel to a compass heading rather than a patient’s vital signs. For those targeting a specific type of sailing—a high latitude ocean crossing, for example—it makes sense to favor a mid-range D/L ratio and the “good performance” range of the SA/D ratio. It’s also important to take a close look at the ballast ratio in conjunction with the boat’s LPS.

Those cruising summer weekends, exploring anchorages close to home, don’t need to lug along as much lead or iron and can look favorably at ballast ratios around 30 percent. However, if it’s a light to ultra-light displacement, a beamy boat with a high SA/D ratio and a shoal-draft keel, beware of a low ballast ratio. This combination means you’ll need lots of friends on the rail when it starts to blow and if you heel beyond the initial righting moment’s sweet spot (around 40-60 degrees) there’s very little secondary righting moment to prevent a knock down.

Multihull sailors put all their eggs in one basket, but it’s a big basket. Extreme beam delivers immense initial stability that peaks around 10-15 degrees of heel. With this powerful heel stopping ability there’s an assumption the secondary righting moment will never be needed. Sailed appropriately, and never caught over canvassed, the initial stability does its job.

However, no multihull designer or builder offers a “can’t be capsized” warranty. Avoiding that outcome is the job of the skipper and crew who must keep careful track of the sail area set, the sea state being encountered and the potential for major fluctuations in wind velocity. Wave face geometry and a changing water plane also affect capsize avoidance. It’s no surprise that the SA/D and D/L ratios of the multihulls in the charter trade are very different than the same ratios calculated for the multihulls that race to Bermuda.

Sailboats, like automobiles, are designed to excel at specific jobs. Just as a Ford F-150 and a Ferrari 488 Spider have decidedly different missions, so does an Island Packet 42 Motor Sailor and a Farr 400. In between these two specialty boats lies a wide range of other sailboats that target a compromise between the two. Sailors, like the boats available, range significantly in how they prefer to spend time on the water.

Hopefully, those seeking to make fast passages end up aboard a boat that can perform up to those standards. And likewise, those out to savor slower meandering and enjoy a comfortable life aboard won’t step below into a cabin lacking head room, festooned with pipe berths, and accessorized with a  two burner camping stove and an unenclosed head. The same goes for performance upgrades and making decisions as to whether to invest in light wind sails or add another fuel tank to bump up range under power. Perhaps both.

Contributing Editor Ralph Naranjo is the author of The Art of Seamanship . He is an adjunct lecturer at the Annapolis School of Seamanship.

RELATED ARTICLES MORE FROM AUTHOR

Thanks Ralph a well put together article with very little bias. Very impressive.

Likewise to above. I’ve tried many times to lay this information out for relatively new sailboat buyers and I wish I could do it half as well as Ralph did in this article. Bravo, Matey

Ralph – recheck your math and formula for SA/D…

Not clear if you multiply the entire formula by 2/3 or juts the denominator – either way it does not seem to come out as you show.

Last year, due to delamination and lots of water intrusion, I replaced the ‘barn door’ rudder on my ‘83 Cal 35 with a slightly shorter and more elliptically shaped rudder. There was a noticeable difference in performance and I moved up more than several places in the one race I enter every year.

D/L is not a dimensionless number (it’s dimensions are are long ton / ft3), neither is SA/D (ft2/ton). Nevertheless, the numbers can be useful at least when comparing boats with similar hull shapes.

Some more discussion of the impact of hull shape (i.e. impact of hard chines, impact of location of max beam, amount of buoyancy in bow & stern, etc.) would be meaningful, as (esp the french) modern cruisers and races have dramatically different shapes than 1970s or 80s cruisers and behave quite differently when compared at similar ratios.

Very nice article. I think the confusion about the 2/3 factor is that the denominator is taken to the 2/3 power. So the equation for denominator is (D in pounds / 64)**2/3. I believe the ** or ^ symbol is missing. Again, good overview with excellent examples. Jim

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Can Sailboats Sail Faster Than The Wind?

Last Updated by

Jacob Collier

August 30, 2022

‍ Sailboats effectively rely on the wind to pick up speed. But can sailboats sail faster than the wind that’s blowing? Is that even possible?

The quick answer to that question is – yes. However, many other factors ultimately determine the top speed of a sailboat and whether or not it can sail faster than the wind. These include techniques, such as foiling, that help you conserve wind energy and use it to boost your sailboat’s speed.

For any beginner who has never been out sailing before, or for those who are thinking of trying out sailing for the first time, this is a great question to ask. Knowing how the wind works to push the sails forward is key to your sailing experience.

Table of contents

‍ Sailing Faster than the Wind

For all those of you thinking this is a typo - it’s not. In fact, ask any sailing enthusiast, and they will tell you that one of the most intriguing things that put sailing at the top of the list for adventurers and thrill-seekers (and those who just love being out in open waters) is that you can literally sail faster than the wind speeds.

However, it is important to add here that it depends on the right conditions and the right technique. That being said, the great news is that even a beginner who has never stepped foot on a sailing boat can also learn how to sail faster than the wind with the right training and effort. While many avid boaters cannot explain the physics of this phenomenon or how it’s possible to beginners, it is commonplace amongst many avid sailors.

To find out just how this is possible, we need to take a look at the experts. For those who follow America’s Cup, you will know that the sailboats there are tremendously sleek and fast. For instance, catamarans such as the AC72 can travel at speeds three times that of the wind, given the right conditions.

In fact, with the right conditions, boats can record speeds of up to 44 knots when the wind speed that’s blowing the sails is just south of 15 knots. So, how does this happen if the wind is the only thing that is powering these boats? To the layman, it may seem like these sailboats are defying the laws of physics. But this isn’t the case at all.

Conservation of Energy

In physics, one often hears the term “ conservation of energy. ” While there is no way for us to create energy when it comes to speed, a parallel theorem exists for the conservation of speed, which is applied to sailing faster than the wind. In other words, the sails in  sailboats  might not be able to create their own energy, but using the right technique, the sails are able to harness more than one kind of wind out there.

This is something that’s often difficult for beginners to grasp, but the technique works similar to how jet airplanes harness airflow in order to fly faster.

True Wind vs. Apparent Wind

The type of wind you feel when you start moving is known as “ apparent wind ” and is exactly the type of wind that sailors and boat enthusiasts harness when they want to sail faster than the wind.

To differentiate between the two, the wind that one feels when they are standing still is called “true wind,” and the wind that one feels while they are in motion is apparent wind. Harnessing both kinds of winds is key to getting the sailboat to sail faster than the wind speed.

So, how do true wind and apparent wind work when it comes to pushing sailboats forward? The short answer is that the sails of the boat need both of these winds to go faster, but both aren’t necessarily performing the same function when it comes to pushing a sailboat forward.

For instance, the true wind helps push the sailboat forwards, as in, when the sails of the boat are perpendicular to true wind and are being pushed from the back. But while true wind helps push the sailboat’s sails forwards, the apparent wind is dragging or pulling the sailboat forward as well.

It should be noted that the sails of a sailboat cannot take full advantage of the force of apparent wind, especially when the wind is hitting flat against the sail. This is why experienced sailors tend to drive their sailboat at a specific angle, and it is not until the boat is traveling at the angle of true wind that the force of both these types of wind kick in and push the sailboat even faster.

Achieving Lift

So, the sailboat is not capturing wind from just one angle; it is harnessing the power of two opposing winds. One that is pushing the sailboat forward and the other that is dragging it forward, which produces lift. This is why sailboats seem like they are in the air during a race because they are traveling incredibly fast.

This is the same lift that one feels when they are driving a car. The next time you are driving a car, stick one of your hands out the side with the palm facing the ground. Now, slowly raise your palm towards the wind, and you will find that your whole arm lifts automatically. This is what the force of lift does in airplanes – and now, you know that this happens in sailboats as well.

Lift is the force that is generated whenever apparent wind bends around the outsides of a sail. This is important to understand because this is where all the magic happens. Since the wind hitting the inside of the sail is moving a lot slower than the wind around the sail, this creates a significant pressure difference, which is what creates the lift that is so important for planes and sailboats to pick speed.

This is why the push and drag that sailors experience when angling the sailboat to catch the true and apparent winds is quite similar to what passengers feel under their feet whenever a plane starts to take off from the runway.

However, while a passenger in a commercial airplane may not have much control over what to do about it, the push and pull sailors sense is what allows them to act accordingly. This can only be achieved through time and a lot of practice. So, the next time you see a catamaran’s hulls raised off the waters, you know that the sailors who are maneuvering the boat are harnessing both true and apparent wind to their advantage.

But that’s not the only trick up a sailor’s sleeve. Those looking to achieve incredible speeds often use a technique that is known as “ foiling .” This is a technique that pushes both of the hulls off the water, which makes the sailboat appear like it is in the air. This is one of the techniques that can be used in smaller sailboats effectively. With just the rudder and the board used to anchor the sailboat, foiling allows the sailboat to reach even higher speeds since there is no drag force that’s slowing down the boat.

The fundamental principle of sailing is pretty straightforward: the sails are used to catch the wind, which is then sent down to the hull and helps move the sailboat forward. While that’s how the sails of a sailboat are supposed to work, if you want to sail faster than the wind, you will need to try out the techniques mentioned above and hone your skills with a lot of practice. So, can sailboats sail faster than the wind? Absolutely!

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Born into a family of sailing enthusiasts, words like “ballast” and “jibing” were often a part of dinner conversations. These days Jacob sails a Hallberg-Rassy 44, having covered almost 6000 NM. While he’s made several voyages, his favorite one is the trip from California to Hawaii as it was his first fully independent voyage.

by this author

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Unmanned boat rescued by Thurston County Sheriff after drifting into shipping lane

The Thurston County Sheriff’s Office safely secured a drifting, unmanned boat that was posing a hazard in the Puget Sound shipping channel last week.

A boating deputy first spotted the boat adrift near Tugboat Annie’s without a registered owner or occupants.

Over the weekend, after storms swept through the area, the boat’s anchor failed to hold, causing it to drift closer to the merge point of the shipping channel.

Despite these movements, the vessel remained unmanned, raising concerns about its potential danger to other ships.

The boat was found even further into the shipping channel on Wednesday, still improperly anchored and unmanned.

Given the risk it posed to incoming and outgoing vessels, the Thurston County boating deputy took action.

The 140-foot anchor line was pulled, and the boat was towed back to a safe harbor, where it was secured to a dock.

Authorities continue to seek information about the boat’s owner.

Anyone with information is encouraged to contact the Thurston County Sheriff’s Office.

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Hull Smoothness – What Matters for Speed?

How much effort should you spend on hull smoothness? We decided to investigate this after seeing a variety of approaches. Many (maybe most) fast sailors put time into polishing the hull, but others don’t bother.

Our primary source for this article is A Smooth Bottom is a Fast Bottom from the GP14 class website. This article is an easy read and the best summary we found. Author Paul Grimes was a Collegiate All-American sailor at Brown University and has experience in hydrodynamics and marine yacht services. We also referred to Sailing Theory and Practice , by C.A. Marchaj

Hull Smoothness and Speed – Data

Hull drag results from several factors. These factors have different names, depending on which book you read.

• Skin friction drag – the friction from the hull sliding through the water. A smooth hull reduces skin friction.
• Form drag – related to the streamlining of the hull and foils.
• Wave-making resistance – related to the slowing effect of the waves produced at the bow and stern by the boat’s movement.
• Induced resistance – due to leeway as the boat slides to leeward while sailing upwind.

Skin friction causes a substantial portion of total drag. Marchaj’s data from towing tests shows that skin friction for an International Canoe is 80% of total drag at 3 knots. Skin friction increases with boat speed, but other the forms of hull drag increase more, so skin friction is only 40% of total drag at 6 knots.

What is the speed advantage of a smooth hull? We could not find definitive speed data. Marchaj’s data only compares a boat with a clean bottom to a boat with a foul bottom. With the same driving force, the clean-bottom boat travels 0.27 knots faster than the foul-bottom boat when moving at 4 knots. The difference shrinks to 0.14 knots when the boats are moving at 6 knots. These are significant differences.

Since we couldn’t definitive data beyond foul and clean hulls, we’ll have to review the concepts of laminar and turbulent flow to get more answers about hull smoothness.

Laminar and Turbulent Flow

The no-slip condition and the boundary layer.

It may be counterintuitive, but the water molecules immediately next to the moving hull are pressed against the hull and adhere to it – they don’t slip. This is true regardless of the hull’s smoothness. These molecules slow down the water molecules “above” them, and so on until the water further from the hull is no longer affected. The affected layer is called the boundary layer. Skin friction drag is determined by the type of flow within the boundary layer.

The type of flow in the boundary layer determines the amount of skin drag.

• In laminar flow, the water molecules in the boundary layer all flow in the same direction – parallel to the hull surface.
• In turbulent flow, the water molecules move more chaotically.

Benefits and Limitations of Laminar Flow

Laminar flow reduces skin friction by as much as 80%, compared to turbulent flow. However laminar flow is fragile. It turns into turbulent flow under several conditions.

• Surface is not fair (bumps or dents).
• Surface is not extremely smooth (highly polished), especially in the forward part of the hull.
• Water is flowing fast. At speeds greater than 4 knots or so, boats can’t sustain laminar flow over the hull length, regardless of smoothness.
• Distance traveled along the surface is long. As the distance traveled becomes long, it becomes impossible to sustain laminar flow, no matter how smooth the hull.

Turbulent Flow

Although turbulent flow causes more drag, there’s still a very thin laminar layer in turbulent flow. The skin drag is minimized if the surface roughness is less than this thin laminar layer.

Conclusions about Hull Smoothness

The theory leads to the following conclusions about how much you should do about hull smoothness.

Fair the Hull

To be competitive your hull should be fair. Small undulations over a distance are not significant. Dents and bumps, especially those with sharp edges are more significant, as they will trip the flow from laminar to turbulent.

Polish to 400 Grit for Acceptable Results

Even with a highly polished hull, boats moving faster than several knots will transition to turbulent flow within the first several feet of hull. In turbulent flow, more roughness is acceptable. Grimes says that sanding to 400 grit is adequate if the flow is turbulent.

Polish to 1200-1500 Grit Equivalent for Best Results

The best chance for sustaining laminar flow is with a very smooth (e.g., 1200-1500 grit or greater) hull traveling at low speeds (light air). Pay special attention to the forward part of the hull, since roughness there will trip the flow to turbulent sooner.

For light air and overall peace of mind, polishing to 1200-1500 grit is not outlandish, but only if you have time to do the more important stuff – like practicing.

Other Hull Drag Factors

Waxing and water beading.

Beading of water on the hull has no effect on skin friction drag. The no-slip condition still holds true. If you put wax on just to get beading, you may make the surface rougher. We’ll see more about this in a future article.

Foil Smoothness

The foils (boards and rudder), being narrower, can sustain laminar flow over their entire surface. Foil smoothness is thus more important. We’ll cover this in a separate article.

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