James Boyd Photography / www.thedailysail.com

Bora Gulari's Moth wing Mk2

The American foiler guru tells of his plans for this year's Worlds on Lake Garda

Friday February 3rd 2012, Author: James Boyd, Location: United States

Detroit-based Moth guru and former World Champion Bora Gulari is already gearing up for this year’s Zhik Nautica Moth Worlds due to take place over 18-26 August out of the Velua Club Campione on Lake Garda.

Gulari, who won the Moth World Champion when it was held on the Gorge in 2009, looks set to be having a prolonged Italian holiday this year as the World Championship for the Melges 24s – another class in which he campaigns fiercely - is taking place in nearby Torbole over 27 July until 4 August.

Over the winter Gulari has been Moth sailing out of Miami and is continuing to develop the kit for his Mach 2.

“We have still been playing around with foils. Everyone seems to think that going small on both foils is good, but my gut feeling is not 100%. There are definitely trade-offs to having a small foil.”

Going small with the lifting element of the rudder foil is something that has been tried by various Moth sailors including the Mach 2’s designer Andrew McDougall and Scott Babbage in Australia, but now it seems focus is shifting to the main lifting foil forward too. “At some point a bigger guys must need a slightly bigger foil,” points out Gulari.

“We have been playing around with sails and masts and we are lucky now that we have John Harris in the States, who lives in Chicago so we have another great person to sail with and tune with - that has been really good for our fleet.” Australian John Harris was the 2008 Moth World Champion but is best known for his lengthy tenure in the Sydney 18ft skiffs, where he usually helms Rag & Famish Hotel.

But the most interesting area of development for Gulari – who like Adam May is a trained aerospace engineer – is that he is working on a new wing.

Gulari’s Mk1 wing for his Moth was sailed in anger by Charlie McKee at the last World Championship in Belmont, Australia and frankly didn’t prove to be the weapon most were expecting it to be.

“The biggest issue was durability,” admits Gulari. “You have lightweight skins attached to a lightweight core and not a whole lot of glue anywhere, when something gets overloaded it is going to break. We have worked on improving that so we shall see how that goes.”

However the big issue was that the wing was simply slow downwind. “We thought ‘this is what this wing should give us’, but it was the exact opposite. It was a bit of a dog downwind.”

According to Gulari the issue with wing Mk1 (which was taken from the moulds of Fred Eaton’s Little America’s Cup-winner C-Class cat wing) was due to a Reynolds number issue. “We had a laminar separation bubble all over the wing. Our Reynolds number was so low, that the drag went through the roof with no increase in lift. It wasn’t like a sailor trim issue or anything – it was weird. I can recognise it now how tell tails flow when they are in a laminar separation bubble - they kind of flow gently back, like you’d expect, but with no vigorousness. It is weird to be able to see it and know what it looks like.”

According to Gulari, with wing mk2, they have started from scratch. “With this one, instead of it being a shrunken down C-Cat wing, we have done it all and changed some of the construction stuff and hopefully made it a lot more durable and user friendly. We have come up with a pretty good way of making rapid prototype parts without having a lot invested money in tooling. So for about US$100-200 we can make new moulds for the big parts.”

But the most significant difference with Gulari’s latest masterpiece is that it will have no slot. For the uninitiated, the slot is the gap between a wing’s vertical elements, allowing air to seep through from the high pressure side to the low pressure side, causing the flow to stay attached further aft on the wing.

“The Reynolds numbers we are operating up aren’t high enough for a slot to really work well downwind,” maintains Gulari. “And we should gain some upwind performance out of not having a slot because we are just not dragging as much funnel area through the wind. Without having a slot we instantly double our Reynolds number. It was the equivalent of having two really high aspect ratio foils on your keel and rudder and trying to go when you don’t have a lot of speed and it stalls and slides.”

Despite being a one piece wing, it will still have camber control, although Gulari says this “won’t be as tricky as on the π28 foiler.” (more here) and he reckons it “should” have a wider performance envelope than his Mk1 wing.

The Moth class has yet to lock down the rules for wings, so in the meantime Gulari has built the new wing at 8.24sqm “which is what the true size of our softsails are. We are trying to stay inside what we believe the spirit of the rule is going to be.

“It is not something I have so much invested in that if this one doesn’t work, it won’t be as big of a circus. We are going to have a lot more time for really testing. If it doesn’t work we are working on other stuff and keep sailing...”

Gulari hopes to be testing the new wing in March, but plans to remain discreet about it until he has a fuller understanding of how it performs. However if it does show promise then the plan is to take it to the Worlds.

While the Moth fleet in the USA will continue sailing and training, Gulari reckons their next big line-up won’t be until the Worlds and he is expecting 10 boats to enter from the US. “The Melges 24 Worlds are also right before, so we’ll probably ship the boat and squeeze some Moths in there. And we will have a Melges full of Moth sailors at the worlds...”

According to Gulari the US fleet is improving dramatically. "A lot of the US guys are getting going again and Anthony Kotoun is coming on strong as a really good Moth sailor, he is putting in the time. And obviously we have Jeremy Wilmot hanging around who hasn’t gone Moth sailing as much as he should!

"We have had a couple of pretty low key regattas in Miami and the competition level is going up quite a bit. It is not a case of just beating people around the race track you have to race hard all the way around and we were having a lot of close races and finishes.”

So watch out watch out – the Yanks are coming...


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