Moth fleet makes big advances in just seven months from NZ
by Richard Gladwell 18 Jul 11:26 NZST
New forestay being fitted - International Moth Class - Lake Garda, Italy - July 2025 © Jana McDiarmid
The just concluded Int Moth Worlds at Lake Garda, Italy were technically much more complex than the 2024 World Championship, held just six months ago in New Zealand.
Mackay Boats' Dave McDiarmid - a three time winner of the prestigious JJ Giltinan Trophy, the world championship of 18ft skiff sailing, was at both events and says the variable conditions at Lake Garda presented several technical challenges for the sailors.
While much of the talk after the event has been over the impact of "steel foils", McDiarmid says that 42 sailors had the carbon and steel foils at the Manly Worlds in New Zealand, and 22 more sailed with the composite foils in Lake Garda.
The innovation at Lake Garda was the introduction of carbon/steel composite rudders, with 36 sailors opting to race with the new rudder build.
"At the New Zealand Worlds, we added the steel main verticals for the centrefoil. From our analysis of the polar performance we found that the carbon steel composites added 1kt of boatspeed in all conditions - and in driving upwind, downwind in any direction. It was just a clear 1kt of speed advantage. And then this worlds, we've added the steel rudder vertical, which probably showded half of the difference/advantage of the main vertical, and was a significant speed increase. You had to have both to be competitive."
The steel verticals in the main foil and rudder are not milled to shape, but are a carbon and steel composite.
"We import the steel, and then we fabricate everything around it," McDiarmid explains. "It's a piece of steel, with carbon components around it."
"The steel vertical allows us to reduce the wetted surface area 22%, resulting in less drag and the consequent speed improvement.
The horizontal parts of the foil, including elevators, are all carbon.
"In New Zealand we had only one prototype composite rudder that one of our designers was using - just to make sure our design was good - because we had such a short turnaround time between the worlds. We could have built more, but we couldn't supply the whole fleeet. We're very conscious that we're not picking and choosing who's going to win. We're giving everyone the opportunity to purchase."
For both the recent 29er Europeans and Moth Worlds, Lake Garda failed to live up to its reputation of turning on the beautiful "Ora" thermal wind, which moves down the alpine lake in the early afternoon.
"We only really got one good day of Ora racing. There was another couple of days, but they were much lighter and very shifty. All racing was sailed in a very shifty breeze and was quite difficult for foiling. The cold water made for plenty of cavitation issues."
Enzo Balanger (25yrs) who was the skipper of the French Youth America's Cup team in 2024, blitzed the fleet in the 2025 Worlds at Lake Garda, improving from 6th overall in New Zealand. While many are quick to point to the technology gain with the new composite foils, McDiarmid believes Balanger's improvement was the time he put into training in his latest generation Mackay Boats BM-3 Moth.
"Enzo was very consistent. He'd spent a lot of time in the boat, and put in a huge effort. He had the same equipment as everyone else.
I would say time in the boat, he put a bridge? effort in. He was very consistent. Yeah, just time in the boat. It was the same equipment as everybody. He had his boat prepared very well, and there wasn't a weakness in his game.
"He had all conditions covered."
"He started well, and sailed well."
"He even broke his forestay in one race, managed to sail to shore without dropping his rig, got to the beach, and swapped in a new forestay. He lost about 10 minutes in total before he was able to re-join the fleet who were still sailing the course."
"He did very well there to get his boat back into shore without dropping the mast, because all sorts of issues occur when you do that."
"He even had time for a sandwich before rejoining the race fleet before he went back out and got back amongst it." now. But you can see from the results, he was very consistent, winning five of the ten races sailed, and his worst counting place was a fourth."
Ballanger finished 12 points clear of Tom Slingsby (AUS) and 14pts ahead of Jake Pye (NZL). Defending world champion Mattias Coutts (NZL) was 12th overall.
Gear breakage was not expected to be so frequent in the fleet, with several competitors breaking forestays.
"It looks like vang loads have increased, so there were quite a few forestay breakages and also with the vangs themselves."
Coutts was 12th overall. "He wasn't quite as dominant as he was in New Zealand, he probably just hadn't put the time into the boat," McDiarmid said.
Jake Pye backed up a second place at Manly with a third in Garda - and in that regard was the most consistent of the top sailors.
"On the first two days he had breakage and little bit inconsistent. But when the gold fleet racing started, he really turned it up and showed everyone what he can do."
"Garda was extremely difficult, as I said before, and it wasn't a regatta where you could expect to turn up fresh from New Zealand it wasn't just turn up from New Zealand, and be on the pace.
"Completely different settings, and techniques for sailing were required, completely different to New Zealand. In comparision New Zealand was rip, shit and bust. In Garda you were trying to ease it through without cavitating. Cavitation was a big issue in Garda, possibly because of the of the water temperature."
McDiarmid says the standard of sailing in the Moths is rising every year - not a surprise as the singlehanded foiling boat, which can be purchased off the shelf - provides excellent training and racing for sailors at the top end of the sport in foiling - be it in America's Cup or SailGP.
"You can't just rock up and win the class. It is awesome, and there's a really good atmosphere in the class as well. If someone breaks something the other competitors are all in to help.
"It was quite cool at the pit stop, because you could sail in and then turn the boat over on the ramp, and there's 10 people fixing it to get it back out there. That kind of thing.
"It was really good to see the big names turn up and basically have fun."