The idea: the Foiling Vampire draws more from the 11 foot International Moth than other foiling catamarans. It is an adapted M20 (see below) currently being fitted with inverted T foils - not the L shaped foils used by the AC72s and C Class catamarans.
Our objective is to build something faster than a Moth and more versatile: if it works it may also be faster than the existing generation of L foil catamarans. We are aiming for something that is easier to launch and sail than the moth, with better performance in light winds.
At the time of writing nothing is proven. In the next few weeks we will know if it works.
The Vampire with C foils in 2013
Competing projects: like everything this has all been tried before. We studied the Off Yer Rocker project, a C class with T foils that lifted well, but was never fast. Another T foil project is Whisper, a very light 18 footer developed by Ron Price and Southampton Solent University. The wands are fitted directly to the foils, and flight is early and stable. It is already sailing successfully on Southampton Water.
Meanwhile orders are being taken for dozens of L foilers from France (Sail Innovation - Flying Phantom) and Holland (Nacra FCS or “Flight control system”). In Texel 2014 the Nacra 20 FCS took line honours, one minute faster than the standard Nacra 20 footer. The Flying Phantom was also fast, but it ran aground hard whilst in the lead.
Why T foils? I am increasingly convinced that the L foils will prove to be a development cul de sac. They are a clever response to AC72 and C class rules that put limits on beam and control mechanisms. The L can be angled to make the height self regulating as in a V foil - see the picture of the Nacra above. The angle of attack can be changed with a control system, and different angles of cant achieved through the curve of the vertical part of the foil. But they also have some disadvantages. There can be a lot of leeway, and foiling upwind has been difficult to achieve. In some conditions it may be quicker to stay in displacement mode.
The Vampire is being developed in a rules free environment. We trust that if the concept works, the rules will adapt.
The moths have been sailing successfully on T foils upwind and downwind for about 10 years. They use a wand to control height and once foiling they achieve impressive speeds. We have calculated that in this year’s Texel conditions a well sailed Moth would have rounded nearly 30 minutes faster than the Nacra 20 FCS - assuming they didn’t meet the same fate as the Flying Phantom.
Who has been involved? I started work on a design brief in September 2013 following the Falmouth International C Class Championship, the "Little America's cup". But I needed an experienced designer to do it properly - dimensions, angles, control systems, theoretical testing and so on . After some persuasion Kevin Ellway, designer of the Exocet Moth came on board.
Kevin shook up the concept from beginning to end. In particular he introduced leeboards instead of daggerboards, which would have a number of benefits: wider effective beam, easier to assemble, easier to launch from a beach, windward foil completely removed from the water, no need to disengage the wand mechanism on each tack. There were also some disadvantages, principally the need to fix the angle of cant.
Kevin’s analysis was converted into CAD drawings by Rich Taylor and into moulds by Lee Morgan. Then it was over to Graham Eeles as builder. The wands have been built by Philippe Oligario, wand manufacturer to the Moth class. Grant Piggott has done the sail modifications, and numerous others have contributed through debate: Simon Farren, Ollie Egan, Finbar Anderson, Simon Northrop, Simon Reynolds, Russ and Penny Clark, Dave Chivers, Graham Bridle, Ollie King, Kyle Stoneham, Neal Pawson and many others - I've probably forgotten someone important. Many thanks to all those involved - even if the project falters I've enjoyed the journey.
William Sunnucks
21 July 2014
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