I wrote this article about 'foiling' in early 2004, and looking back through it now it already seems like ancient history. Actually, in the fast-moving world of flying boats, it probably is! But really we're still at the frontier of this exciting new territory in high performance sailing, and this article helps put the progress with hydrofoils on dinghies into perspective.   Make a note of the word ‘foiling’. Ten years from now, it may just have entered the lexicon of sailing in the way that ‘gennaker’ and ‘asymmetric’ have done over the past decade. The small boat world has gone foiling mad, thanks largely to the exploits of a Melbourne-based International Moth sailor called Rohan Veal. Using a fixed wing on the rudder and an adjustable wing on the daggerboard, Veal has mastered the art and science of flying at high speed a few feet above the water. With the 10-foot hull raised above the surface, Veal has reduced hydrodynamic drag to a fraction of that experienced by a traditional waterborne Moth, and has translated this into vastly superior performance. It takes about 7 knots of true wind to generate the necessary power to get his craft up on the foils, but once it starts flying, Veal reckons on being able to achieve 12 knots of boatspeed upwind in just 7 knots true.

He has also translated this into spectacular success on the race track. Last year he came third in the International Moth World Championship, winning a few races by some impressive margins but not quite having mastered the subtleties of foil control downwind in big waves. However, by the Australian Nationals he had stepped up another gear, foiling his way to eight successive races by margins of between three and nine minutes. Veal now reckons to be travelling around the course at speeds comparable to a 49er or International 14, and has regularly clocked over 20 knots on the GPS.

For a dinghy class that is meant to pride itself on innovation and development, Veal’s pioneering exploits have met with no small measure of criticism from other Moth sailors. “They asked me to take my pictures down off my website, because they thought what I was doing wasn’t representative of Moth sailing,” says Veal. “So I put more pictures up instead.” And with a flood of new entrants into the class, inspired by Veal’s photos and videos, it looks as though the naysayers are rapidly becoming outnumbered. At Australian $3,000 (approx £1,300), the hydrofoil conversion kit for a Moth is not really that expensive.

 

In Weymouth, Olympic campaigners Adam May and Graham Vials have teamed up with local boatbuilder Linton Jenkins to design and build three identical foiling Moths, in readiness for the European Championships this July. Both May and Vials finished runner-up for Olympic selection in the Tornado and 470 respectively, but they have substituted Olympic disappointment with unbridled excitement at the prospect of flying above water. May believes other Olympians will jump in to the Moth after the Athens Games this August. “I was out at the Miami Olympic Regatta recently, playing one of Rohan Veal’s videos on my laptop and within a minute I had 20 Tornado sailors standing around me, amazed at what they were seeing.”

 

Clive Everest has also been inspired to draw the lines for his own foiling machine. Best known as the designer of successful singlehanded classes, the RS600 trapeze boat and the RS300 hiking dinghy, Everest is an unreformed speed junkie. He has raced International 14s, 18-foot Skiffs and most recently an A-Class catamaran. He also has a history in Moths, including designing the world championship-winning Moth of the early 90s and finishing second in his own right as a sailor. He was also part of a pioneering group who experimented with foiling over a decade ago. “I was involved with Moths when we were experimenting with a tri-foil arrangement, but then the class banned it,” he says. “These days at 13 stone I’m too heavy to campaign a Moth competitively; you’ve got to be about 10 stone and I think the weights might come down even further with the foils. But I was totally inspired by what Rohan Veal was doing so I decided to design my own boat, with no rules or restrictions to worry about.”

 

His own RS300 design, itself a derivative of the Moth, has proven fast and easily driven in light winds so Everest took this as the basis of his new foiler. “The only time the hull’s going to be in the water is in light winds, so the RS300 seemed like a good place to start.” Because Everest only expects to be sitting on the water in conditions of 7 knots or less, he has had the top 150mm of freeboard chopped off the RS300 hull to save weight, and has commissioned Richard Woof of RMW Marine boatbuilders to construct the hull of carbon.

 

To this hull Everest is attaching carbon trapezing racks for added leverage. The rudder and rudder box are standard 49er equipment, with the addition of a T-foil wing to the base of the rudder. The rig consists of a carbon mast and fully-battened Mylar sail. So far, the basic configuration differs very little from the Rohan Veal Moth, but where it differs is in Everest’s approach to the foil arrangement. “I have adopted a tri-foil arrangement similar to what you see on a commercial passenger-carrying hydrofoil ferry,” explains Everest. “We experimented with this set-up on the Moths 10 or 15 years ago but because the class banned it, Rohan has had to go for his more complex T-foil arrangement.”

 

Unlike the T-foil system, Everest’s tri-foil configuration has no moving parts and there is less tweaking and calibration involved as a result. The hull is supported on two carbon foils, one from each trapeze rack, angled at approximately 45 degrees underneath the centre of the hull, with the T-foil rudder providing a small element of lift at the transom. It will run closer to the surface and will provide a more stable ride than the high-flying Moth of Rohan Veal. It may look a little less spectacular but should prove equally fast, if not faster, with anticipated speeds of up to 25 knots. “I wanted something simple and maintenance free. I’ve got a young family and limited time to go sailing, so the tri-foil will just let me get on with the fun part,” explains Everest, who plans to club race his foiler during the summer in Chichester Harbour. “The aim is to give the fast twin-trapeze boats like the International 14s a good run for their money.”

 

Everest’s Achilles heel is going to be in the sub-foiling conditions when all that hydrofoil becomes added drag, but he has given himself a big rig and big foils to promote early foiling, at the expense of reduced top speed. And unlike the Moth, he has the added turbo of a small gennaker which he will hoist downwind in light to moderate conditions. “Because of the amount of apparent wind, the sail is very flat - more like a Code Zero than a gennaker. But once the wind is above a Force 3 to 4 I expect to be generating enough power around the course with just the mainsail.”

This has been the experience of Rohan Veal, who finds himself sailing with the boom on the centreline all the way round the race course, such is the apparent wind generated. Not only is it faster, it’s more comfortable. “It means I can hike out on the wings downwind, which is a lot more pleasant and stable than wobbling around in the middle of the boat,” says Veal. However, downwind in big breeze and waves has proven a little too exciting, with the boat prone to launch off the back of a wave high into the air, resulting in a potentially painful and expensive nosedive. In these conditions Veal tends to reduce the foils’ efficiency and sail the boat more conventionally, with the hull in the water.

 

It is one of the shortcomings of the self-levelling system that Veal, the test pilot, has developed with John Ilett of Fastacraft, the Moth’s designer and builder. But it is an ingenious system nevertheless. A free-swinging carbon wand is attached to the bow. The inboard end of the wand is attached to a pulley system along the foredeck, which in turn attaches to the push-rod which runs down through the inside of the daggerboard and controls the pitch of the wing. As a wave strikes the bow-wand and knocks it backwards, it sends a message via the pulley system which then alters the angle of the daggerboard wing to cope with the changing wave state. Once the wave has passed and the wand swings back to a more vertical angle, the daggerboard wing levels out again. Ilett and Veal have spent hours, weeks and months getting such an intricate sensing mechanism to work satisfactorily, but Port Philip Bay - where Veal does the bulk of his sailing - provides a severe test with its short, difficult chop. An electronic sensor would smooth out the system even more but this is illegal under Moth rules.

 

An International 14 in Western Australia tried a similar system to Veal’s a couple of years ago, which produced some spectacular pictures but never proved itself on the race course. The class moved to ban such developments, for fear of costs going through the roof. Instead it opted for a half-way house where just one hydrofoil is allowed, either on the rudder or daggerboard. Now the class norm is to have a T-foil rudder, which raises the transom a few inches above the water, reducing hull drag and pitching moment, and adding a few percentage points of boatspeed.

It was Paul Bieker who introduced T-foils to the 14. The Seattle-based designer was subsequently hired to join the design team at Oracle Racing, to bring some left-field thinking into the America’s Cup programme. However, we didn’t see any of Larry Ellison’s boats sprouting T-foils down in Auckland, and it is safe to assume that the hydrofoiling technology of lightweight planing dinghies is not directly transferable to the world of displacement keelboat sailing. Nevertheless Bieker specified a T-foil rudder for a 30-foot lightweight cruising boat commissioned by former Olympic Champion and America’s Cup sailor Jonathan McKee. While the T-foil had virtually no effect on the yacht’s sailing performance, Bieker claimed it made the boat much more efficient under motoring conditions, making it much more economical on fuel consumption.

That may be about as relevant as hydrofoiling developments get for the keelboat world. But for multihulls the potential is far greater. Whether it is desirable is another matter, according to Nigel Irens. He says hydrofoils could be put to good use on large multihulls such as the G-class round-the-world record breakers, mainly in helping lift the windward hull clear of the water sooner than normal. But he also points out the potential risks of such technology, saying that the moment the windward hull and its T-foil broke clear of the water there would be a sudden lifting force that would be in danger of flipping the multihull on to its side. He says the T-foil would provide an element of suction to the water that once it broke clear would suddenly disappear, leaving you with an effect not dissimilar to a tug-of-war team suddenly and unexpectedly letting go of the rope, causing the other team to fall over.

 

Irens certainly shied away from testing such technology when drawing the lines of Ellen MacArthur’s B&Q trimaran, and believes it is not appropriate for ocean-going craft. He has also discouraged the ORMA 60-foot tri circuit from going down this route, both on safety and cost grounds. Instead, the recent generation of ORMA tris have limited themselves to using curved foils which provide a combination of lateral resistance and vertical lift, but without the full-blown and potentially hazardous effect of full hydrofoiling. This is as far as they should take it, in his view.

However, Irens has seen hydrofoiling at work on a 37-foot trimaran which he designed for a Florida-based professor of hydrodynamics called Sam Bradfield, who retains a lifelong passion for speed despite being well into his 90s. “That has achieved 30 knots downwind,” says Irens, “although around a race course it wouldn’t be as fast as a conventional trimaran of the same size.” This is the opposite of Rohan Veal’s experience in the Moth, who has been surprised to find that his most impressive performance gains compared with conventional Moths have been when sailing upwind.

 

On a larger scale, the French 60-foot experimental craft Hydroptere remains the most impressive showcase for hydrofoiling. The brainchild of Eric Tabarly, this project has gone on in fits and spurts for the past 20 years, although there are plans to pick up developments again. In the past Hydroptere has suffered from being too heavy but advances in lightweight composite construction make large-scale hydrofoiling now seem more feasible.

 

The trouble with hydrofoiling is it requires quite strict conditions in which to operate successfully. It has proven highly efficient at getting lightweight craft to move rapidly in flat water conditions up to moderately fast speeds. But none of the current attempts on the world speed record are using hydrofoils in their bid to better the 46.52 knots set by Yellow Pages back in 1993. Southampton-based Aussie Paul Larsen has opted for a low-drag planing concept for his SailRocket project. “Hydrofoils seem to work very well up to 25 or 30 knots and then you start to get serious problems with cavitation,” he explains. “So for anyone trying to break the 50-knot barrier it doesn’t seem the way to go.”

That won’t concern the new generation of dinghy foilers, however. They’re having too much fun learning to fly. British boatbuilder Richard Woof, who has been constructing Clive Everest’s new foiler and whose more conventional boats currently hold the International 14 and 18-foot Skiff world titles, predicts a new sport is about to be born. “If you look at the current Moths flying around above the water, they look ridiculous,” he says. “They’ve got all that hull up in the air which they just don’t need. You don’t need all that freeboard, you could have a much simpler structure for foiling.” Woof envisages purpose-built craft that would be much smaller and lighter. “I can see a new sport where we only bother going out on the water if we can get up on our foils.”

 

Andy Rice  www.SailingTalk.com

 

 

I wrote this article about 'foiling' in early 2004, and looking back through it now it already seems like ancient history. Actually, in the fast-moving world of flying boats, it probably is! But really we're still at the frontier of this exciting new territory in high performance sailing, and this article helps put the progress with hydrofoils on dinghies into perspective.   Make a note of the word ‘foiling’. Ten years from now, it may just have entered the lexicon of sailing in the way that ‘gennaker’ and ‘asymmetric’ have done over the past decade. The small boat world has gone foiling mad, thanks largely to the exploits of a Melbourne-based International Moth sailor called Rohan Veal. Using a fixed wing on the rudder and an adjustable wing on the daggerboard, Veal has mastered the art and science of flying at high speed a few feet above the water. With the 10-foot hull raised above the surface, Veal has reduced hydrodynamic drag to a fraction of that experienced by a traditional waterborne Moth, and has translated this into vastly superior performance. It takes about 7 knots of true wind to generate the necessary power to get his craft up on the foils, but once it starts flying, Veal reckons on being able to achieve 12 knots of boatspeed upwind in just 7 knots true.

He has also translated this into spectacular success on the race track. Last year he came third in the International Moth World Championship, winning a few races by some impressive margins but not quite having mastered the subtleties of foil control downwind in big waves. However, by the Australian Nationals he had stepped up another gear, foiling his way to eight successive races by margins of between three and nine minutes. Veal now reckons to be travelling around the course at speeds comparable to a 49er or International 14, and has regularly clocked over 20 knots on the GPS.

For a dinghy class that is meant to pride itself on innovation and development, Veal’s pioneering exploits have met with no small measure of criticism from other Moth sailors. “They asked me to take my pictures down off my website, because they thought what I was doing wasn’t representative of Moth sailing,” says Veal. “So I put more pictures up instead.” And with a flood of new entrants into the class, inspired by Veal’s photos and videos, it looks as though the naysayers are rapidly becoming outnumbered. At Australian $3,000 (approx £1,300), the hydrofoil conversion kit for a Moth is not really that expensive.

 

In Weymouth, Olympic campaigners Adam May and Graham Vials have teamed up with local boatbuilder Linton Jenkins to design and build three identical foiling Moths, in readiness for the European Championships this July. Both May and Vials finished runner-up for Olympic selection in the Tornado and 470 respectively, but they have substituted Olympic disappointment with unbridled excitement at the prospect of flying above water. May believes other Olympians will jump in to the Moth after the Athens Games this August. “I was out at the Miami Olympic Regatta recently, playing one of Rohan Veal’s videos on my laptop and within a minute I had 20 Tornado sailors standing around me, amazed at what they were seeing.”

 

Clive Everest has also been inspired to draw the lines for his own foiling machine. Best known as the designer of successful singlehanded classes, the RS600 trapeze boat and the RS300 hiking dinghy, Everest is an unreformed speed junkie. He has raced International 14s, 18-foot Skiffs and most recently an A-Class catamaran. He also has a history in Moths, including designing the world championship-winning Moth of the early 90s and finishing second in his own right as a sailor. He was also part of a pioneering group who experimented with foiling over a decade ago. “I was involved with Moths when we were experimenting with a tri-foil arrangement, but then the class banned it,” he says. “These days at 13 stone I’m too heavy to campaign a Moth competitively; you’ve got to be about 10 stone and I think the weights might come down even further with the foils. But I was totally inspired by what Rohan Veal was doing so I decided to design my own boat, with no rules or restrictions to worry about.”

 

His own RS300 design, itself a derivative of the Moth, has proven fast and easily driven in light winds so Everest took this as the basis of his new foiler. “The only time the hull’s going to be in the water is in light winds, so the RS300 seemed like a good place to start.” Because Everest only expects to be sitting on the water in conditions of 7 knots or less, he has had the top 150mm of freeboard chopped off the RS300 hull to save weight, and has commissioned Richard Woof of RMW Marine boatbuilders to construct the hull of carbon.

 

To this hull Everest is attaching carbon trapezing racks for added leverage. The rudder and rudder box are standard 49er equipment, with the addition of a T-foil wing to the base of the rudder. The rig consists of a carbon mast and fully-battened Mylar sail. So far, the basic configuration differs very little from the Rohan Veal Moth, but where it differs is in Everest’s approach to the foil arrangement. “I have adopted a tri-foil arrangement similar to what you see on a commercial passenger-carrying hydrofoil ferry,” explains Everest. “We experimented with this set-up on the Moths 10 or 15 years ago but because the class banned it, Rohan has had to go for his more complex T-foil arrangement.”

 

Unlike the T-foil system, Everest’s tri-foil configuration has no moving parts and there is less tweaking and calibration involved as a result. The hull is supported on two carbon foils, one from each trapeze rack, angled at approximately 45 degrees underneath the centre of the hull, with the T-foil rudder providing a small element of lift at the transom. It will run closer to the surface and will provide a more stable ride than the high-flying Moth of Rohan Veal. It may look a little less spectacular but should prove equally fast, if not faster, with anticipated speeds of up to 25 knots. “I wanted something simple and maintenance free. I’ve got a young family and limited time to go sailing, so the tri-foil will just let me get on with the fun part,” explains Everest, who plans to club race his foiler during the summer in Chichester Harbour. “The aim is to give the fast twin-trapeze boats like the International 14s a good run for their money.”

 

Everest’s Achilles heel is going to be in the sub-foiling conditions when all that hydrofoil becomes added drag, but he has given himself a big rig and big foils to promote early foiling, at the expense of reduced top speed. And unlike the Moth, he has the added turbo of a small gennaker which he will hoist downwind in light to moderate conditions. “Because of the amount of apparent wind, the sail is very flat - more like a Code Zero than a gennaker. But once the wind is above a Force 3 to 4 I expect to be generating enough power around the course with just the mainsail.”

This has been the experience of Rohan Veal, who finds himself sailing with the boom on the centreline all the way round the race course, such is the apparent wind generated. Not only is it faster, it’s more comfortable. “It means I can hike out on the wings downwind, which is a lot more pleasant and stable than wobbling around in the middle of the boat,” says Veal. However, downwind in big breeze and waves has proven a little too exciting, with the boat prone to launch off the back of a wave high into the air, resulting in a potentially painful and expensive nosedive. In these conditions Veal tends to reduce the foils’ efficiency and sail the boat more conventionally, with the hull in the water.

 

It is one of the shortcomings of the self-levelling system that Veal, the test pilot, has developed with John Ilett of Fastacraft, the Moth’s designer and builder. But it is an ingenious system nevertheless. A free-swinging carbon wand is attached to the bow. The inboard end of the wand is attached to a pulley system along the foredeck, which in turn attaches to the push-rod which runs down through the inside of the daggerboard and controls the pitch of the wing. As a wave strikes the bow-wand and knocks it backwards, it sends a message via the pulley system which then alters the angle of the daggerboard wing to cope with the changing wave state. Once the wave has passed and the wand swings back to a more vertical angle, the daggerboard wing levels out again. Ilett and Veal have spent hours, weeks and months getting such an intricate sensing mechanism to work satisfactorily, but Port Philip Bay - where Veal does the bulk of his sailing - provides a severe test with its short, difficult chop. An electronic sensor would smooth out the system even more but this is illegal under Moth rules.

 

An International 14 in Western Australia tried a similar system to Veal’s a couple of years ago, which produced some spectacular pictures but never proved itself on the race course. The class moved to ban such developments, for fear of costs going through the roof. Instead it opted for a half-way house where just one hydrofoil is allowed, either on the rudder or daggerboard. Now the class norm is to have a T-foil rudder, which raises the transom a few inches above the water, reducing hull drag and pitching moment, and adding a few percentage points of boatspeed.

It was Paul Bieker who introduced T-foils to the 14. The Seattle-based designer was subsequently hired to join the design team at Oracle Racing, to bring some left-field thinking into the America’s Cup programme. However, we didn’t see any of Larry Ellison’s boats sprouting T-foils down in Auckland, and it is safe to assume that the hydrofoiling technology of lightweight planing dinghies is not directly transferable to the world of displacement keelboat sailing. Nevertheless Bieker specified a T-foil rudder for a 30-foot lightweight cruising boat commissioned by former Olympic Champion and America’s Cup sailor Jonathan McKee. While the T-foil had virtually no effect on the yacht’s sailing performance, Bieker claimed it made the boat much more efficient under motoring conditions, making it much more economical on fuel consumption.

That may be about as relevant as hydrofoiling developments get for the keelboat world. But for multihulls the potential is far greater. Whether it is desirable is another matter, according to Nigel Irens. He says hydrofoils could be put to good use on large multihulls such as the G-class round-the-world record breakers, mainly in helping lift the windward hull clear of the water sooner than normal. But he also points out the potential risks of such technology, saying that the moment the windward hull and its T-foil broke clear of the water there would be a sudden lifting force that would be in danger of flipping the multihull on to its side. He says the T-foil would provide an element of suction to the water that once it broke clear would suddenly disappear, leaving you with an effect not dissimilar to a tug-of-war team suddenly and unexpectedly letting go of the rope, causing the other team to fall over.

 

Irens certainly shied away from testing such technology when drawing the lines of Ellen MacArthur’s B&Q trimaran, and believes it is not appropriate for ocean-going craft. He has also discouraged the ORMA 60-foot tri circuit from going down this route, both on safety and cost grounds. Instead, the recent generation of ORMA tris have limited themselves to using curved foils which provide a combination of lateral resistance and vertical lift, but without the full-blown and potentially hazardous effect of full hydrofoiling. This is as far as they should take it, in his view.

However, Irens has seen hydrofoiling at work on a 37-foot trimaran which he designed for a Florida-based professor of hydrodynamics called Sam Bradfield, who retains a lifelong passion for speed despite being well into his 90s. “That has achieved 30 knots downwind,” says Irens, “although around a race course it wouldn’t be as fast as a conventional trimaran of the same size.” This is the opposite of Rohan Veal’s experience in the Moth, who has been surprised to find that his most impressive performance gains compared with conventional Moths have been when sailing upwind.

 

On a larger scale, the French 60-foot experimental craft Hydroptere remains the most impressive showcase for hydrofoiling. The brainchild of Eric Tabarly, this project has gone on in fits and spurts for the past 20 years, although there are plans to pick up developments again. In the past Hydroptere has suffered from being too heavy but advances in lightweight composite construction make large-scale hydrofoiling now seem more feasible.

 

The trouble with hydrofoiling is it requires quite strict conditions in which to operate successfully. It has proven highly efficient at getting lightweight craft to move rapidly in flat water conditions up to moderately fast speeds. But none of the current attempts on the world speed record are using hydrofoils in their bid to better the 46.52 knots set by Yellow Pages back in 1993. Southampton-based Aussie Paul Larsen has opted for a low-drag planing concept for his SailRocket project. “Hydrofoils seem to work very well up to 25 or 30 knots and then you start to get serious problems with cavitation,” he explains. “So for anyone trying to break the 50-knot barrier it doesn’t seem the way to go.”

That won’t concern the new generation of dinghy foilers, however. They’re having too much fun learning to fly. British boatbuilder Richard Woof, who has been constructing Clive Everest’s new foiler and whose more conventional boats currently hold the International 14 and 18-foot Skiff world titles, predicts a new sport is about to be born. “If you look at the current Moths flying around above the water, they look ridiculous,” he says. “They’ve got all that hull up in the air which they just don’t need. You don’t need all that freeboard, you could have a much simpler structure for foiling.” Woof envisages purpose-built craft that would be much smaller and lighter. “I can see a new sport where we only bother going out on the water if we can get up on our foils.”

 

Andy Rice  www.SailingTalk.com