The Mothmen Prophecy

A revolution is starting in the dinghy world as Rohan Veal's win at Moth's Australian national shows foiling has come of age

Performance dinghy sailing is in the process of taking a quantum leap with the latest developments in foil technology in the International Moth class.

Foil-born boats are hardly new. A hydrofoil patent was lodged in the US as long ago as 1894 and foil-born sailboats, in more different configurations than it is possible to imagine, have been built sporadically in different corners of the globe ever since.

Small foilers have traditionally been created by speed sailor/inventor types. There have been a number of highly successful examples in the past such as Ben Wynne's Mayfly, A-Class record holder in the 1970s and James Grogono's foil-born Tornado Icarus, the B-Class holder until the end of the 1980s. More recently one of the most successful was Russell Long's Greg Ketterman designed Longshot, the present A-Class record holder (at 43.55 knots) that has since been productionised and turned into the Hobie Trifoiler. Another production tri-foiler is the Windrider Rave.



In France for several decades designers and sailors have been experimenting with the use of foils offshore in large multihulls. The legendary Eric Tabarly was probably their most famous exponent and his trimaran/foilers Paul Ricard and subsequently Cote d'Or were both had giant angled foils on their outriggers. A similar configuration was used with very much less success on Alain Gabbay's white elephant of an 85 footer Charles Heidseick during the 1980s and more recently on Alain Thibault's equally breakage prone L'Hydroptere. Lifting foils are also used in the 60ft trimaran circuit, although they are retractible for light conditions and their use is more to reduce wetted surface area rather than to make the trimaran airborne.

The benefits of foils are obvious. Stick a Bruce foil (angled V-shaped foil or a V split in two) or a straightforward inverted T-foil under a hull and it develops more lift the faster the boat sails. Eventually the hull lifts clear of the water and with hull drag suddenly reduced to zero the boat immediately accelerates to Warp speed.

However there are a significant number of drawbacks to using foils too. Compared to non-foilers they have terrible light weather performance through having the combined drag of both foils and hull in the water. While ideal in flat water, traditionally they don't like waves which can cause the foils to stall. They can prove problematic to manoeuvre as the boat inevitably slows down and drops back into the water during a tack or gybe. Once up on to the foils it is hard to keep the boat from launching itself as the foil develops more and more lift or going down the mine when it doesn't. If you are lucky enough to get to a high speed on them a whole new set of problems develops with cavitation and ventilation of the foils.

We have a theory that the slow acceptance of lifting foils into mainstream yacht racing is because traditionally they have been used on speed sailing boats rather than on the race course. Usually fitted to multihulls they have suffered prejudice and it is true that they often look both ugly and ungainly. Until now.

Foil development in the Moth class has been rife for several years particularly in Western Australia. Windrush catamaran builder Brett Burville (below) pitched up to the 2000 Moth Worlds on a boat with 45degree angled Bruce foils. Despite not having sailed the boat very much Burville was able to get airborne in 10 knots of breeze, was often first to the weather mark and tacked quickly, but the boat proved hard to manage sailing downwind in a chop. On Burville's Moth the foils were attached to the extremity of the racks and subsequently the class voted that this was tantamount to it being a multihull and banned it.



With this one avenue of development nipped in the bud, attention turned to a straightforward aft rudder and board arrangement with an inverted T-foil at the bottom of each. The most successful of these has been the Fastacraft Moth as developed by John Ilett in Perth. Each of the T-foils has a trailing edge flap to 'maintain altitude'. The flap on the rudder is operated by the helmsman using a clever motorcycle throttle twist grip-type arrangement on the tiller. The flap on the daggerboard trims itself automatically by a sensor-arm mounted at the bow - a clever idea that has been used on a number of other foilers.

In his Fastacraft Moth White Knuckles Express that Aussie sailor Rohan Veal turned the class on its head by demolishing the competition at the Australian Nationals on Lake Cootharaba in January. In the ten race series he won the last eight straight each by a margin of three to nine minutes.

Two points were worth noting from Veal's win. Firstly conditions were perfect for foiling - 15-20 knots in flat water. Secondly it proved that Veal has fully mastered the art of airborne sailing around a race course. In some way the Moth is the perfect vehicle for making the transistion to foils - the hull of a modern Moths is only about six inches wide and they are highly tippy beasts even when they're not airborne. Getting up on foils is a small step.

Rohan Veal says the transition for him happened in just a matter of months. He sailed a foiler for the first time in May last year and in anger at the Worlds in Les Sables d'Olonne last year in which he finished third.

So what is it like to sail one? Veal says that the T-foil on his centreboard takes care of most of the foiling thanks to the automatic pitch adjustment rig on the bow. The T-foil on the rudder allows him to change manually the fore and aft trim of the boat.

"You don’t use it that much because the automatic pitch control mechanism at the bow for the main lifting foil that does its job reasonably well," he says of the rudder foil. "But your body weight is the biggest factor. So upwind, you can be smoking along doing 12-14 knots and you can trim the rudder a bit to flatten the boat off to go faster, so you don’t have so much angle of attack. And downwind in waves you want to push the bow down because sometimes it pitches too high. So it is very good to use it for that."

Sailing a foiler in waves is a technique issue which Veal maintains he has mastered. "When you launch out of the water it is usually because of a wave - the [sensor] wand at the front of the boat springs back and develops too much lift or if it comes out of the back of a wave. I’ve learned how to control that now - it is all down to body weight and position."

Veal says that one of the principle differences in technique from sailing a non-foil Moth is in how you shift you body weight. "Normally with a Moth it is very unstable, so you are shifting you body weight from side to side. With the foiler you are doing the opposite, you are shifting backwards and forwards, you are hardly shifting in and out at all." Unusually the foils have the effect of stabilising heel. "Upwind for instance we would normally move a fair way forward round where the centreboard case is but on a foiler you you are at the back of the boat and you get the bow of the boat right out of the water."

A criticism normally levelled against foilers is that they only operate in a small window of conditions. Again Veal disputes this. "At the moment the configuration that I’ve got going, which we are testing, we have got it working in all conditions. In about 7 knots of wind it will foil. Then I’ve had it out in 25 knots on the bay, in really rough conditions and it goes fine.

"The biggest advantage which we didn’t even realise was sailing upwind in waves, because you don’t have to punch through waves all the time and lose so much energy - you just go straight over the top of them. We didn’t realise that was a possible until we went to France and sailed it in the big waves.. Now we’re making bigger wings and we should be able to foil with it in 5 knots of breeze."

Anything less than 5 knots he admits is a pain, but then it is too a non-foiler Moth.

The biggest performance gains over the non-foil Moth are upwind. "The thing with the Moth is that it is so light and narrow that is really hard to push through the eye of the wind in a breeze," says Veal. "With this, the boat is not touching the water so you let it foil head to wind and then it flops over, and then you tack in no time and you are up and foiling again in probably a second or two."



If a typical upwind leg takes 10-15 minutes Veal says it is possible to put 1-2 minutes on non-foil borne Moths. Reaching Moths are hair-raisingly fast anyway, but the foiler is still a shade faster, but Veal reckons the margin in closer to 10-15 seconds. It is a similar story running.

One important point that Veal makes is that it is easy to over-complicate boats like this. On the class websites for example there has been talk of replacing the mechnical sensor wand at the bow with an electronic one. "It is really important from my experience to keep things simple as possible. The simpler the better. They try things that are a bit more sophisticated but we always come back to simple things. This system may look complicated but it is really simple. It is to me at least." Compared to the cumbersome early foilers in the class with Bruce foils mounted on their wings, the Fastacraft set-up for example looks very straightforward.

While around the world Moth sailors, Mothies as they are known, have been up in arms about the move to foilers Veal says that people are coming round and dissenters are increasingly forming the minority. "People who have been comfortable with the class for a while and they don’t want to see any more development go through - they are the ones resisting. But anyone who embraces technology, which we should do because we are development class, they can’t get enough of it. Even if they don’t foil they think it is good for the class." Veal says the class has survived dramatic gear and design changes in the past and it will survive this. In fact if anything the move to foils we predict will attract people to the class - since it is now gaining so much publicity.

One way the class are looking to limit a potential arms race is by having a one configuration rule so that if you do the first race on foils then you stick with them for the rest of the week regardless of whether it is blowing 5 knots or 35. Veal is in two minds about this. He believes that championships are the best arena to try out new kit and where you can experiment. The Moth is a development class, not an Olympic class, he says. However equally he hates having to make decisions about the gear he'll use...

At present the UK is attempting to play catch up when it comes to foilers but there are a number of serious players getting involved most designing their own boats.

Andy Paterson of Cowes-based Bloodaxe Boats, builders of the Axeman range of Moths, is typical of those who have seen the videos of Rohan Veal and others foiling on their Moths and have been immediately gripped by it. Paterson first fitted foils to his Moth back in 1994, but soon discarded them. He is now making another attempt. While it is tempting simply to mimic the Fastacraft foil set-up Paterson, along with Ian Ward in Australia, is attempting to take it a stage further using an appendage configuration similar to that pioneered on Rich Miller's hydrofoil sailboard in the US. The set-up they are working on comprises an inverted Y-foil on the main centreboard and a forward 'rudder' with small auto-adjusting T-foil on it. The advantage of the Y foil is that one element of the 'Y' is providing lift while the other is providing lateral resistance and compared to the Fastacraft set-up is that there is less foil in the water and therefore less drag.

Having been beaten to the Tornado spot in the GBR Olympic squad Adam May has donned his designer's hat and has come up with his own foil-borne Moth, admittedly using foils from Fastacraft as Rohan Veal uses. 470 Olympic sailor Graham Vials is having the sistership. Roger Angel is also another developing a foil borne Moth while Simon Payne has imported a Fastacraft Moth.

In other classes Alaistair Richardson and Pete Greenhalgh last year were playing with a foil-born 49er. A fully foiling International 14 has been sailing in Australia, although the class have chosen to stick with single foils for the time being. Perhaps one of the most radical boats will be the new foiler of RS designer Clive Everest, that is based on a highly suped-up version of an RS300 (more on this tomorrow).

While Rohan Veal appears to be one of the first people to get foiling sorted in a monohull dinghy race context it will be fascinating to see how this technology filters through to other classes. Are the Moths leading a revolution in sailing or will foiling merely become a separate discipline within the sport as Vangard Boats' Steve Clark predicts?

Would, for example, it work on yachts? A problem is one of displacement. Moths have the distinct advantage of weighing a feather light 30kg... if foils are to reach monohull yachts it is likely that they would only work at high speeds, but who is to say that a retractible foil set-up would be impossible to develop?

Stay tuned on thedailysail this week for more articles about the latest foil technology...

To see the videos of Rohan Veal airborne - click here
To see videos and photos of the Hobie Trifoiler - click here