Design supremo

The Daily Sail spoke to Alinghi's design co-ordinator and America's Cup veteran Grant Simmer about why SUI64 proved so fast

Grant Simmer was design co-ordinator for Alinghi, overseeing every aspect of the highly complex and refined process that it takes to create an America's Cup Class yacht.

A 47 year old Australian, Simmer was part of the Australia II team in 1983 and has been integral to all Australia's AC challenges since Alan Bond's famous wing keeler and was with America True in 2000. Until signing on with Alinghi in 2000 he ran North Sails Australia.

Alinghi was the fastest ACC yacht in Auckland and although getting the very secret specifics of why this was the case is impossible the mild mannered Australian provided The Daily Sail with some insight.

Simmer says that for the 2000 Cup most boats were an evolution of Team New Zealand's San Diego winner NZL32, with differences in their beam and sectional shape. "Then Laurie Davidson made the double knuckle bow which is a way of making the boat look longer. This time round we were the first with the Laurie bow to push more volume into the front of the boat." They increased this further prior to the AC (see photos of the unveiling here)

"Getting the optimum beam has been important," continues Simmer. "OneWorld and Team New Zealand were beamier than the other challengers, although we were close. Reduction of flair in the topsides is a trend that all designers have been following. When the boat heels, it sinks and gets longer with less flair in the topsides. So now the boats are extremely narrow with slab sides, quite ugly to look at, but very good boats upwind."

Regarding NZL82, Simmer says the team were worried about it (in our interview with him , Rolf Vrolijk said that they had been testing hulas - Alinghi called them J-Los - on their second boat, SUI75). "The effect of the hula was they could make the boat shorter but have the flatter stern slope so that when they heeled they got back to a similar sailing length - so being shorter they had more sail area."



Alinghi's tank testing took place in St Johns, Newfoundland

While most of the challengers, he thinks, were similar in terms of their length and sail area, the hula enabled NZL82 to carry more sail area although this may have been a mixed blessing. "The funny thing is we've been testing mainsail area and over about 12 knots upwind we didn’t find an advantage with a bigger main. So we didn’t feel we needed more sail area to go upwind. Of course it is always an advantage downwind. I was really scared they were going to be really fast downwind. But it seems that the gap associated with the hula and perhaps the drag associated with the longer bulb balanced the effect of the extra sail area."

In the end the Swiss boat proved faster downwind, particularly in heavy airs, contrary to race pundit expectations. "We thought it would be faster downwind, but it seems that the hula gets pulled away from the hull at high speeds with the tests that we’ve done with similar shapes, because the flow has been accelerated around that shape and you are getting lower pressure: So there’s a force actually pulling the hula away from the hull increasing the gap. And once you get up around 12 knots it seems to be pretty significant. I don't know if their hula was a lot stiffer than the one we used, but I was surprising as it got windier that they didn’t get fast using their sail area downwind. If anything with the S sail we looked a little faster."

It is of course typical of the self-depricating nature of Alinghi's designers that Rolf Vrolijk, in charge of hull development, should attribute their success to the rig and sail development. Similarly Simmer whose expertise is in rig development naturally thinks the hull was a distinct improvement.

"I actually think we had quite a radical hull," he says. "Only really Stars & Stripes were more radical than us in terms of hull shape: sectional shape, topside flair, volume distribution. You've got to give credit to Rolf - he drives that whole thing here, together with the tank testing that Manolo [Manuel Ruiz de Elvira] did. The boat always looked really good in the tank and we were always a bit nervous because we thought it looked what we thought was quite radical. As a team we are relatively conservative so we built 75 as a more conservative boat, but we never thought it would be as good as 64 even though it was our second boat. So it was a defensive strategy, 75. It’s a shame we didn’t have more faith in our ability and our prediction tools!

"Starting this campaign I didn’t think there’d be a lot in hull development, but in the end hull development was really significant. Having said that we did a huge amount of work on our rigs, subtle things with the geometry, getting the rig to fit with the main and the whole business of the jumper adjustment with the big headsails - we spent a lot of time on that and we got a lot of benefits. On our rig development was Dirk Kramers, Murray Jones and Pete Lawson - really good guys all of them."

Alongside the rig team and Mike Schrieber, who was in charge of sail development, the part of Alinghi design team responsible for all things above deck was the envy of Halsey Street.

"The stability of the mainsail leech sailing upwind, getting the big headsail to fit around the rig without endless crushing up against the jumpers - all those things have been critical," continues Simmer. "I think our rig and sail combination was superior to any of the other teams. Certainly the challengers - Prada in particular had to modify their whole philosophy with their sails, to try and match where we were at when they came here last September. And Oracle modified their trim towards ours. They started off with flatter headsails with a lot less twist and they ended up with our trim."

Simmer emphases the importance of the interaction of the headsails and the main and their having complimentary shapes. The opposite of this seemed evident on NZL82 in race four when the mainsail seemed to be regularly backwinding while the headsail was sheeted bar tight. "We have got quite a lot of twist profiles in our genoas," says Simmer. "If you look at the twist profiles, it looks similar to the mains as opposed to some of the other teams which had tighter headsail trim and twisted mains."

The Alinghi design team are also attributed with coming up with the innovative bat spreaders, used to stabilise the leech of headsails, once the headsail is sheeted in tight against them. "It came from Team New Zealand a little bit last time because they had 'pushers' and 'flippers' - as they’re called - and Simon [Daubney] was pushing that. He was working on the headsail shape and the twist profile together with Mike Schrieber, the sail designer, and the rig designers."

On Alinghi mast many of the fittings were on the front of the mast and it was thought that this was an attempt at trying to make the rig twist (a little like a rotating mast) to improve the efficiency of the airflow over the mainsail. Simmer denies this.

"Because of some of the fitting locations on our rig, people had commented on thinking that we were trying to twist the rig a lot," he says. "These rigs twist because of the position of the mainsail leech and we were allowed to have asymmetric jumpers, so that creates a bit of twist in the rig as well. But the fact is the spreaders are rigidly attached to the mast and the leeward shroud in our rigs is tight so the mast can’t twist a lot.

"Rigs always rotate around the tip of the windward spreaders, but if you have tension in the leeward shroud, which we do because it is important for the stability of the rig, it twists 4-5 degs, like everyone's does."

Aside from the bat spreaders, the Alinghi design team also developed the flat topped mainsails, an idea borrowed from the 60ft trimaran class. "That was our Swiss sail designer Patrick Nazuay. They’d been doing it on the multihulls, and he’d been using flow to look at how the sail would fly and twist and it just looked better and better.

"And we were nervous about building it because there were issues - would the mast overbend with the big head because it puts a higher moment at the top of the rig? Would we have trouble even hoisting and lowering the main because of the big stiff battens up high? But none of those things were a problem. Warwick [Fleury], the mainsheet trimmer, was working closely with Patrick and they just kept developing it. And gradually it got bigger then. Other people were copying it and making their's bigger and ours were getting bigger at the same time."

Alinghi were also unique in chosing to have their masts built by Hall Spars and not by the all conquering Southern Spars. "It was actually a decision made before I joined the team," says Simmer. "We were always nervous that Southern couldn't deal with the number of customers that they had. Each team requires a lot of managing. Prada may have built five rigs. Oracle – they had a huge rig programme. It is impressive what Southern achieved what they achieved. On the other hand we are happy with Hall because we got their total attention. We got really nice masts, delivered on time."

In total Alinghi had four masts - the first delivered to them in the Med when they were sailing their training boat - SUI59. The second was delivered to them in Auckland before the final two racing rigs were built. "We broke mast three, right near the hounds when a top mast backstay fitting broke," says Simmer. "Martin Marine were able to repair it - it was impressive they added 3kg and the repair we could never see - it didn’t alter the bend characteristics either."

The overall impression one gets from Simmer is that there is still considerable development work to be had out of ACC yachts, despite the present batch being fourth generation. Russell Coutts agrees with this and at the announcement of the AC2007 protocol yesterday explained that this is why they aren't changing to a different type of boat.

With four years to cook up yet more innovation, one can be guess at what the Alinghi supreme team will come up with next.

Spot the difference: the top picture below was SUI64 taken during early trials in Auckland.

(more photos of Alinghi can be seen on the subsequent pages)