F18 - the Hot new Capricorn (Part I)

by John Curnow on 5 Nov 2012 Every now and then a racing boat comes along that has success written all over it. Such is the new F18 Capricorn catamaran, Designed by multihull expert Dr Martin Fischer and built by an Australian marine company with a long, long multihull pedigree, Performance Sailcraft Australia (PSA). the boat is already delivering the goods

Dr. Martin Fischer lives in warm and windy Noumea and that is exactly how he describes the conditions there, which is definitely perfect for cats. This fluid dynamics legend has been and still is, attached to some of the most exciting wind-powered, high-speed, water born craft around. Add to that equation that he’s French and their favourite nautical device is the multihull, and you’ll see that the whole thing is definitely a good match.

Like any dedicated marine enthusiast, Martin is always striving for perfection. Currently he has a new A-Class and the 10-metre CG32 on the go, with another small cat in the mix, as well. Busy. And that does not even touch on his work in climate change. However, our main area of attention here is to his very recent enhancements to his original design of the Formula 18 Catamaran known as the Capricorn.

What follows, are the thoughts that Martin and Chris Caldecoat, the GM of Performance Sailcraft Australia, the highest volume boat builder in Australia have and an explanation of the pathway that has got them to the point of releasing the new Capricorn GEN 2.

Firstly though, if you have not seen an F18 cat in full flight, then you’re certainly missing something.

Even more so, if you have not seen a cloud of these cats approach the top mark, head off to the hitch and then bear away for the set, then the noise from water, sail and humans can only be described as an intoxicatingly, raucous rush.

‘It was really good and a lot of fun to come back to the Capricorn after the Wild Cat. Chris had the initiative, as he’d raced the Capricorn and really liked the boat. At that time we all knew that the Capricorn was a really quick boat, but a bit nosey, so quite difficult to sail downwind. The rights for the Capricorn had come back to me as a result of the creation of the C2, so Chris asked me to have a look at improving the original and here we are.

Chris is a very good sailor and has had a lot of input based on all his observations and knew exactly what he wanted to improve, so this is the way we progressed together’, said Martin.

‘The F18s are bit like the V8 Supercars and NASCAR, where if you win on the Sunday, you sell on the Monday’, said Chris.

‘They are a people orientated brand and the only sailing class that I know, to which this phenomenon occurs. F18s are the biggest cat class around the globe and I believe this is because it covers a wide demographic and is relatively affordable. Perhaps that’s a bit similar to Etchells.’

‘If you look at the F18 races, you can have two 18 year old kids out there, a girl and a boy, just like the new mixed Olympic multihull, or a 65 year old steering with a young bloke up the front. The latter is still winning races at the World Championships, so they mightn’t win the regatta overall, but every now and then the dog has its day and that’s enough to keep them in the class, which keeps people buying and it goes back to being a true club sport.’

‘F18s have a crew weight limit of 150 kilos, so you can either put a 90 and 60 kilo crew together, or you can both be 75. If you go under, you do get a little lead penalty, which means it all stays very competitive and that all helps to ensure a widespread appeal, as well.' said Chris.

So the original Capricorn was designed by Martin and built in Bendigo. Its name was more of an homage to the particular degree of latitude that runs through Martin’s adopted home, than to any goat bounding around the hills of country Victoria. Not only was it a sales success, but out on the track it took its fair share of World Championships, too.

More info at www.capricornsailing.com.

After five or six years, it has been superseded by the not new model and we’ve already seen how Chris, from PSA and Martin, with more accolades than an honour wall, had the genesis of a great idea.

Martin explains, ‘What we did is to basically take the original shape and just put a sort of wedge in between the middle. It’s a bit more complicated than that, but the principle was adding a flat underwater shape, because we knew from the newer boats that it doesn’t do any harm. With the first Capricorn, the boat was slightly rounder and narrower, so the easiest thing to do was to just add a flat part in the middle, along the centre line, and that is what we did.’

‘Another key change was to increase the freeboard a bit, mainly in the rear beam. The main beam basically stayed where it was but with the rear beam, we increased the height by about 60mm. This is to account for the fact that in strong winds and choppy conditions, the original rear beam hit the waves when you are sailing downwind. That is quite uncomfortable, as it really slows the boat down and can even lead to capsize, because if the rear beam hits a wave and you are at full speed then you really get a sort of shock. The guy on the trapeze may lose balance and then you capsize.’

‘Now with these modifications, it means more volume overall and more freeboard at the back. You can push the boat out much harder than before. Chris tells me that with the new boat you can really go hard downwind and it seems upwind it’s full of speed. Overall, it seems the modifications were quite successful’, commented Martin.

‘I have a huge passion for this class. I’ve sailed every type of F18 and the Capricorn is by far the quickest. It just needed some work to sort out its performance downwind, as it was too hard to sail. Martin and I have taken the original boat, kept the same look, spent a long time on the drawing board (i.e. computer) developing the modifications and it’s now a bigger, faster boat’, said Chris.

‘The new Capricorn flies and it goes better upwind, too. There are a whole heap of technical changes we have made to it, especially in terms of the design, location and construction of all the foils. For instance, the rudders are underneath the hulls and we have two-metre long, solid carbon centreboards, which have been moved further for’ard, the beam’s come further aft and the whole geometry of the boat has changed.’

‘From about 10 metres away, the boat’s profile looks like that of the original Capricorn, but it is wider and there is a lot more volume up for’ard. So much so that you can nearly make it plane up wind’, said Chris.

That’s all wonderful, but if you race a class with a box rule, then you either have to compromise or get creative to meet certain key elements, such as minimum dry weight, which for the F18 is 180 kilograms. Compromising can get dangerous, but creative can allow you to build the proverbial better mousetrap. It would appear that with the Capricorn, the latter has served as the guiding principle.

We’ll be back with just what Martin and Chris have done with the new Capricorn and why their combined creative talents have created a perfect F18 cat. One that can be sailed far easier and still be very dangerous to the scoreboard, as their very impressive results showed on the weekend at the NSW F18 titles on Botany Bay have showed.