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Fear of flying

by Dougal Henshall 31 Aug 04:00 PDT
Fear of flying © Rafal Czepulkowski

In the recent massive missive on having fun courtesy of the scow hull form, 'All the Fs in sailing' there were a few other Fs that were missing.

According to the RYA, there are two other crucial Fs that apparently need their own article as the mantra of today is that 'Foiling is the Future' (of sailing). There is plenty of evidence to support their assertion, as foiling dinghies are increasingly apparent and even the most grounded of observers can hardly fail to see how many foilers, of various shapes and sizes, were on display at the Dinghy Show. Like the RYA, the media love foilers to the point that the number of pictures they feature in are quite disproportionate when considering the number of boats involved.

It helps of course that foiling is highly fotogenic (another F there if you spell it like that), but at the same time there are signs that just as with the skiff revolution of the 1990s, that foiling may already be reaching something of a plateau. So much of the regular dinghy sailing that goes on, both in the UK and elsewhere takes place at locations that are simply not 'foiling friendly'. It now seems likely that foiling will continue along its current trajectory as part of the move towards high-tech, high value and high performance elite end of the sport. Yet those doomsayers who hold the view that foiling is little more than the latest fad, are missing the fact that foiling has actually been around as long as conventional racing dinghies. The understanding of foiling and the practical experiments that have seen boats starting to fly have come courtesy of some amazing innovators who are very much the equal of those who drove the development of conventional dinghies.

If we go back in time by more than 150 years, the principles of hull performance were still in their infancy, with some of the great technical minds of the day, such as William Froude, exploring the relationship that exists between a ship's hull and the water it floats in. As sail gave way to steam, with engines that became ever more powerful, there would be the need to develop many of the rules covering wave making and skin friction that are still in use today.

At the same time, other equally innovative minds were trying to master the complexity of heavier than air flight. A London based engineer, Thomas Moy, was already exploring flight through his interest in ballooning, but he then branched out into the nature of aerofoils when, inspired by the flight of the Albatross, he started experimenting by towing sections of shaped wood in the Surrey canal. Although Moy decided not to progress with the models he made, preferring instead to focus on aircraft, but his work can now be seen as ground breaking in that their laid the foundations for the developments that would soon be taking place on the River Seine in Paris.

The wonderfully named and slightly eccentric Horatio Phillips, who did much to advance the science of aerofoil sections by creating a wind tunnel using streams of steam, helped created a foiling catamaran. This was also steam powered, yet would achieve a speed of over 30kt, which was an incredible achievement for the time. The problem though was in the power to weight ratio, an issue that was tricky to address when relying on steam engines to provide the forward motion. This barrier to progress would be solved with the arrival of the much lighter internal combustion engine and when the Italian inventor Enrico Forlanini used a 60hp petrol engine to drive large airscrews, he finally had the solution to the power to weight equation.

His designs for a set of foils were highly sophisticated, as the lifting surfaces were arranged in a ladder format, so as forward velocity increased and the boat lifted up, the immersed foil area decreased. The foils themselves were made from metal with the angle of attack being controlled by the helm and by 1906, on Lake Maggiore, Forlanini reached a speed of almost 37kt.

Powered foiling was now clearly understood, albeit as a fringe activity, but the development of a sailing boat that was both light enough and powerful enough to reach a foiling speed would take another half century.

It is hardly a coincidence that the next step in the story would take place in the same timeframe as the start of what the IYRU (World Sailing) would come to call 'performance sailing', as rigs became more powerful and lighter. The next step would be the 'big' one and it would be taken over in the USA when Gordon Baker created a slender hull boat, that had V foils mounted on a transverse beam located immediately aft of the mast, with control and steering being maintained by an aft mounted single V foil. Cat rigged, with a fully battened main, the boat would comfortably foil when sailing to windward, with Baker being possibly the first sailor afloat to experience apparent wind sailing (something that ice yachts had long taken for granted).

Just how quick the boat was is hard to establish, for many of the performances are based on the speed of motorboats who were pacing the foiling dinghy, but a figure of 1.5 times the true wind speed seems realistic. The problem came when Baker tried to sail the boat downwind, as it had an alarming tendency to pitchpole.

Nevertheless, the success of this boat came to the attention of the US Navy, who were themselves just starting to explore the military applications of foiling craft. Baker was commissioned to come up with an improved version of his boat with the result being the Monitor. Baker's choice of name was significant as Monitor was the name of the radical ironclad that had proved to be so significant 90 years earlier in the American Civil War.

The Monitor of the 1950s would offer a number of high-tech (in 1950s technology) innovations, with twin laddered V foils forward and a steerable V foil aft. The main foils were under the control of an on-boat mechanical computer, which could adjust the main foils independently of each other and soon the 30ft long canoe hulled boat was not only clocking up speeds that were reported to be breaking the 30kt barrier, but was reportedly looking to complete a tack whilst still foiling. Without a properly recorded speed run it is not possible to say just how fast the Monitor really was, but almost certainly the boat was the fastest sailing craft yet developed.

There have been questions asked about what speeds Monitor might have achieved, with some thinking that the power to weight ratio indicated that the claimed speeds had been grossly exaggerated. Recent analysis of this film clip however that timed the passage of spray away from the foils suggests that the Monitor was truly quick!

Although the US Navy interest in foiling was coming to an end, there was still time for one more major innovation to come from their interest, though this time the innovator was an English engineer, Christopher Hook, who was looking at the potential for a high speed troop carrier.

Although mechanically complex, Hook's development was simplicity itself, for it comprised what in yet another 50 years would reappear as 'the wand'. The description in the Patent Application refers to a 'forwardly extending and hydrofoil moving means'. In practical terms Hook's 'Hydrofin' used a surface skimming arm mounted ahead of the forward foil that would control the angle of incidence through a mechanical linkage.

Through the 1950s and 60s sail powered foiling remained a fringe activity, pursued mainly by those for whom the driving force was overcoming the technical issues that any innovative advance would present. For mainstream sailing, greatly increased boatspeeds were now accessible to all, courtesy of the increasingly efficient catamarans, with classes like the Tornado and Unicorn offering stunningly fast performance from a relatively simple 'over the counter' package. At the same time though, the performance that these cats could achieve suggested that they could be the platform for a new series of fast foilers. One of the first to explore these new opportunities would be James Grogono, whose first iteration of a foil equipped Tornado called Icarus proved that the new generation of innovators were working along the right lines. Grogono's developments were almost too good, with his Tornado Icarus fully foiling at quite low speeds, which suggested that the foils themselves were too big and could be reduced in size.

A following version went too far the other way, with foils that failed to produce sufficient lift, but James Grogono was both determined and persistent, with each new version of Icarus solving yet another problem (though sometimes revealing new ones). One problem that faced James, just as it had faced the foilers that had gone before him was 'just how quick is quick', for though apocryphal stories abounded about boats hitting magically high speeds, none of these had ever been properly recorded. An attempt was made to host a weekend at Burnham on Crouch, up on the East Coast of the UK, that featured a 500 metre run through two timing gates. A number of strange boats entered, few of which would bother the timekeepers, with the star of the foilers being Icarus, though embarrassingly a standard, non-foiling Tornado went fastest of all and with a lot less in the way of fuss.

Despite the lack of a speed breakthrough, the idea of Speed Sailing as a standalone activity had taken root, with Weymouth Speed Week becoming established down on the waters of Weymouth Harbour, with cash prizes for successful boat. One of the great success stories from these early events was Peter Hansford's clever little single handed cat Mayfly, which in flat water could hit speeds of 16kt plus. The downside of the Mayfly set up was that even quite small waves could cause a foil to break the surface and thus lose lift and when this happened at speed some of the wipeouts were quite spectacular.

Just as with Icarus, Mayfly would be a 'work in progress', with an early improvement being changing the aft foil to an inverted T. The original foils had been hand-made in wood, but as Mayfly developed, aluminium foils were created and before long the boat was practical enough for pretty much any competent helm to jump aboard and get airborne. Top helm and marine photographer Guy Gurney was at Weymouth covering Speed Week, when he got a chance for a late afternoon sail on Mayfly and recounts the sudden acceleration as the hulls cleared the water, then the near silence, despite the fact that the boat was obviously going very quickly. Guy went on to highlight another issue with the foiling Speed Week hopefuls, in that all the clever innovation couldn't overcome any shortcomings in sailing ability. Talented he might be, but Phillip Hansford was more a cyclist than a sailor, with his speed runs often characterised by swoops up and down off the foils. Icarus in the meantime had no such issues, as James Grogono had been a top class Finn sailor: Guy also got the chance to crew for James on Icarus to take photos and found the bigger boat more stable - and quick!

The single inverted T foil, located on the centreline would be a significant step forward, as would a development of an old idea, the Christopher Hook Hydrofin that gave automatic control of the foils, allowing the helm to concentrate on the rig and on the water ahead. Mayfly would eventually reach 23 kt and the ever-improving Icarus 26 kt, yet these speeds had to be taken into consideration with the advances that were taking place elsewhere, as a standard Hobie 16 blasted across the Speed Week course at a fraction shy of 20 kt, and even a weighty Shearwater cat, when well sailed, could post a best speed of 16.7 kt. Yet the best of the multihulls and the fastest of the foilers would all fall foul of that power to weight ratio, as speed sailing became dominated by the new fastest things afloat, the windsurfers.

Just as quickly as they had taken off, the foilers had been overtaken as the best route to the ultimate in outright speed sailing competitions, but the benefits of reducing hull drag were just too attractive to ignore completely, as far sighted designers continued to look at other potential practical applications.

505 designer John Westell was decades ahead of his time by considering the use of foils for offshore multi-hulls, but it would be the late, but very great, Eric Tabarly who would take the concepts of big boat foiling forward. With Eric's long term support, the 60ft French foiling trimaran Hydroptère would show the world that not only were there advantages of size, with this amazing boat taking a number of world speed records by comfortably breaking the 50 kt barrier, but the boat was equally at home in a blue water setting, as the boat made a fast passage from Los Angeles to Honolulu.

Just how quick Hydroptère might possibly be was seen when she undertook a speed run off the coast of southern France and had finally raised the bar above 100 km/h - 56.3 kt, until it all went wrong and she pitchpoled before capsizing!

Although there had been some fantastic contributions from various British innovators, moving forward there was an increasingly expressed view that the UK's contribution to foiling was "pitifully small", with one observer noting that "foiling was now as rare in Britain as cricket was in the foiling nations". That criticism would have a short shelf life, as elsewhere the UK was leading the world in the first dinghy based practical application of carbon fibre. One fleet where the arrival of carbon technology would be greeted with open arms (a lot of classes quickly said - and still say NO) would be the International Moths where innovation comes as standard. Foiling had already been tried by Australian Frank Raison on a Moth as far back as the mid-1970s but whilst this had been a qualified success, the weight of the hull and rig precluded further development of this idea.

A decade later the idea would be resurrected, this time at Weston Sailing Club, on the eastern shore of Southampton Water, which already had an enviable reputation of being a hot spot on innovation across a number of classes. Leading the forward thinking Moth sailors based there would be the likes of Clive Everest and Ian Ridge, who together experimented with a bowsprit and asymmetric spinnaker on a Ghoul Moth, then a wing mast on a Unicorn cat, before sitting Ian's Aero Moth atop a winged keel intended for tank testing. Ian is just another sailor from that pool of talented innovators and in his youth, he was already experimenting by putting small aircraft wings under model boats. The winged keel was positioned at the daggerboard slot, though this was the only lifting surface, as the rudder was left in the standard configuration.

The morning of the test sail, the winds were light, so the boat was towed behind the club RiB, which once again proved all the previous thinking about foiling, as the Moth quickly lifted up and out of the water. The sea breeze had kicked in by the afternoon at which point Ian's boat achieved foiling under sail power alone, for the Moths were clearly ahead of everyone else in that all-important power to weight question, that is such an essential aspect of foiling. With the only foiling surfaces being under the centre of the hull the whole set up was very unstable, but the principle of a foiling Moth was more than proven. However, the whole idea would then get kicked into the long grass as the owners of the test keel were unhappy about their use in public, the club was unhappy about the mis-use of their RiB and the whole question of a foil within the Class Rules was unclear.

However, the International Moths had never been a class to stand still and having gone fully carbon, super skinny, minimum displacement hulls, about the only option left was to look again at foiling. Isle of Wight based Moth sailor Andy Paterson hung foils of the aft corners of his wings and with a third foil at the bow could not just foil, but do so with a degree of stability that pointed towards a foiling future. The action then returned to Australia with a great deal of innovation taking place, but as yet no one had pulled all the various elements of racecourse foiling together (as distinct from the just seeking out the quickest over a measured straight line distance).

The big breakthrough would come when the Millennium World Championships came to Western Australia, as Brett Burvile entered his foiler, and in the prevailing brisk conditions, would prove the boat's all-round capabilities by winning not just one race but two. His boat still relied on a three foils format, with Burvile reverting to a 'two at the front, one at the back set up', which although stable enough to allow foiling around the course would still provide some spectacular capsizes.

Brett's success would come though at a price, as the Moth fleet would now have to suffer something of schism between those who thought that the 'anything goes' mindset in the Moths should be nurtured and those who thought that foiling was a development too far.

This though was just an early 'Marmite manifestation' of feelings in general about foiling and soon there would be those who proclaimed it to be the future, or the counter argument that it had even less to do with dinghy sailing than the antics of the sail flapping windsurfers. Concerned that allowing foils to be mounted on the wing bar extensions would create a form of trimaran, the Moths were able to come up with a happy compromise that gave a green light to foils but only if the foil exited the hull below the waterline. The race to meet these conditions would be won by Australian John Illett who perfected the rudder and daggerboard inverted T foils, with ride height being automatically controlled thanks to a modern version of the earlier bow wand that had been trialled by Christopher Hope. The modern Moth was now fully evolved and, in the hands of first Rohan Veal and then the likes of Simon Payne, the sailing techniques of sailing a foiler, in all conditions and on all points of a racecourse, would be perfected.

First sailors achieved foiling gybes, then tacks would be mastered, though the most visible change would be in the heeling of the boat markedly to windward once foiling. Sailing the boat like this helped the main foil to generate lift to windward whilst reducing drag. Simon, who sailed a sister ship to Veal's Championship winning 'White Knuckle Express' recounted that though basically the same as today, the wands were more flexible and control over the rudder tab was via a flexible Bowden cable. This left the helm needing to use his bodyweight a lot more to keep the fore and aft trim in control, but even so the Moths were racing ahead. When he started Moth sailing in 2004, the 'Badge of Honour' was to be in the 20 kt club; just a few years later this was a standard level of performance with the place to be well past the 30 kt mark!

In just a couple of years the top speeds for the International Moth had nearly doubled - how long will it be before a hard charging Moth sailor breaks the 40kt barrier? - video © Tom Slingsby

In just a few seasons foiling had now leapt forward from a fringe activity seen at Speed Weeks to being right at the heart of the mainstream of dinghy sailing, with speeds to match, plus the Moths were now foiling all the way around a racecourse. The pace of progress and high profile success of the Moths would not go unnoticed, and if there is one part of sailing where the search for the smallest of advantages will always be pursued it is in the America's Cup. When the New Zealand AC Team first took an interest in the development, the first and probably biggest question was one of legality, with the question being not so much one of 'would it work' but more a case of will it fly in the courts as well.

Moreover, it is one thing making an ultra-lightweight 11ft dinghy foil, but would a fully crewed 72ft cat lift off and if so, would it be stable enough for the heat of AC competition. Emirates Team New Zealand (ETNZ) had the additional complication of not wanting to show their hand too early, so the early experiments were carried out using a 33ft long catamaran on a quiet lake away from the public gaze. At least, that was the plan, but as so often happens things didn't quite work out as the boat came off its trailer on the motorway, creating a spectacle of a different kind!

Just like with Ian Ridge at Weston 20 years earlier, ETNZ started off by towing their test bed behind a speed boat, before moving to sail power on the open sea. As their experience grew, the ability to commit huge levels of technical and financial resource would solve the problems of scaling up the foiling equations to that needed to get nearly 6,000kg of 72ft catamaran plus 11 crew airborne on scarcely a couple of square metres of foiling surface.

Just how good the new boats were was seen when the New Zealand boat reached a speed of 47.5 kt in just 22 kt of wind, yet even this wasn't enough to wrest the Cup away from the Americans. Although for the next running of the Cup Series in 2017 the boats had been trimmed down to just 50ft, the speeds remained nearly the same, with a top speed of 47 kt being recorded, though the media hyperbole would talk about the AC boats doing "50kt plus".

The two America's Cups that had been run with foiling boats, at San Francisco and then Bermuda, had not only been a huge media success, but had raised the prospect of big boat foilers heading offshore, with the French multihulls being quick to come up with the next generation of what would become the 'Ultimes' - 100ft long fully foiling tris. Leading the work on this would be Guillaume Verdier, who had been closely associated with the foil development on the Emirates Team New Zealand AC boat. In a measure of how rapid the pace of development had become, Guillaume had come up with a foiling concept that introduced a degree of self-stabilisation. As the boat went faster, more of the foils curved lift area cleared the water, which resulted in the boat starting to make more leeway, which slowed the boat down. Even so, boats such as Gitana 17 would still be able to reel off long distances at incredible speeds above 40 kt. At the launch of Gitana 17, the talk was of raising the most miles sailed in a day to the incredible figure of 900 miles in a 24 hour period - which would require the boat to sustain a figure of 32.5 kt for the period. At the time it may have seem fanciful, but before long the records would be tumbling, with Francois Gabart covering 851 nautical miles in a day... singlehanded.

There seemed though to be a limiting factor on how much faster these boats could go, with cavitation on the foils being identified as being the primary issue once speeds pass the magical 50 kt barrier. In yet another iteration of the foiling story, this was exactly the problem that the team behind the Vestas Sailrocket identified, leading them to take a radically new approach to a boat that wouldn't just take the outright sailing speed record, but would smash it. With this goal in mind, Paul Larsen went back to that thinking that had been such a part of Weymouth Speed Weeks, with plans to develop a boat that would go faster in a straight line, over a measured distance, than anything else had gone before. Key to this would be to overcome the problems of foil cavitation at very high speeds, which required a rethink in the shape and sections of the foils. There were other challenges facing the Vestas Team, as they pushed ahead with plans for a boat that could generate an apparent wind three times that of the true wind. This meant a new approach to not just foil design, but rig theory and high tech construction, as the power/weight equation would play a key part in the attempt to take the record away from the kite-surfers. When all the pieces of the puzzle came together, their innovative and then successful approach to solving the issue of foil cavitation resulted in a new World Record of over 65kt - just short of 80 mph/120kph+!

The amazing and record breaking run of the Vestas Sailrocket, when which more than doubled the winning performances of boat such as Mayfly and Icarus. It would be easy to pigeon-hole the Vestas Sailrocket as interesting by lacking in practical, real-world applications, but looking back at the comments made by the designers of the Ultime off-shore boats, there will be a time when the technologies will migrate over into a boat aimed at offshore record breaking. In just 8 years more than 24 hours have been shaved off the transatlantic record, which now stands with Banque Populaire V at 3 days 15 hrs, yet there is talk of the mythical 2 day crossing as a target, which would require something close to Sailrocket speeds, non-stop, for 48 hours!

Back in the closer to the real world of shorthanded offshore sailing, foiling is now seen as the route to success in the top flight events such as the Vendée Globe, with boats such as Alex Thomson's exciting new Hugo Boss, a 60ft, 7500kg monohull able to bring apparent wind sailing to what is still essentially a keelboat. The monohulls seem to be grabbing all the media headlines now given that the 36th America's Cup will be sailed in boats that will be right at the leading edge of development, with 75ft long boats that will (given the right conditions) foil from start to finish.

However, looking back, practical foiling started in almost the smallest of boats, the 11ft International Moths and migrated upwards, but already the technical advances are filtering back down. Advanced foil design has seen the Quant 23 burning up the Swiss lakes, whilst the Moth itself has spawned a number of follow on designs, the A Class cat went foiling, as did the Olympic Nacra 17, and even the Cherubs have proved that when they can get it right, foiling is both fast and fun.

But... coming around full circle, is it the future?

The answer is probably that it is just one future in a sport that may well end up having a number of them. Foiling is certainly not a cheap way to get afloat, with some of the super-competitive Moths costing between £2,000 and £3,000 per foot, a situation that in part has given an advantage to the more accessible spin-offs like the WASZP. Yet foiling has shown that it could be the one genre with the ability to buck the trend that suggests that the higher the performance of a boat, the greater has been the loss of critical mass in recent years. But it matters not if the boat is 11ft or ten times that, if it is not widely accessible and widely acceptable, then the danger will remain that foiling might be a future, indeed a pinnacle of the sport, but one that will remain a minority.

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