Faster faster
The AC50s used in Bermuda were hardly dull, but they were still considered a bit underwhelming by Russell Coutts and Larry Ellison for the new SailGP series. So former Team New Zealand designer Mike Drummond and current Ineos Team UK technical director Nick Holroyd were asked to give them wings… James Boyd looks at the result
The AC50 got (considerably) faster Setting out to change the AC50 flying cata- marans, as raced last year in Bermuda at the 35th America’s Cup, into a highly turboed, one-design fleet of F50s ready for 2019’s SailGP circuit was a unique challenge Russell Coutts presented to former Emirates Team New Zealand/SoftBank Team Japan technical director Nick Holroyd, plus the assembled team of designers, engineers, hydraulics and systems specialists and the team from Core Builders Composites.
36 SEAHORSE
Mercifully much of the AC50 was already one-design with the rule specifically written to encourage teams to concentrate their design efforts for the last Cup on foils and their wetboxes, wing engineering, and the control systems for both foils and wing, rather than on hull shapes, beams, mast tubes or wing configurations, and so on. ‘From my perspective, it was a very pleasurable project because you sit there for three years [during the last AC cam- paign] slapping your forehead up against the class rule and then suddenly you can wipe that away and just go for it… yet without taking a lot of concept risk because you’re still playing in a domain that you know and understand. ‘There was enormous potential to speed the boats up,’ explains Holroyd, who headed the AC50-F50 conversion/upgrade until recruited as lead designer of the latest British Cup challenge. ‘When the F50 pro- ject started I actually thought the brief might be to tame them in some way, but in fact very much the opposite happened. When- ever there was a choice between “simple” or “performance”, the choice was always “performance”.’ Such is the Coutts way. One of their principal challenges was trying to equalise the fleet. The six boats that will kick off SailGP in Sydney in February comprise the Oracle Team USA, Team Japan, Artemis and Land Rover BAR AC50s plus two new ones made from the Oracle tooling, held at the US team’s builders, Core Builders Composites in Warkworth, New Zealand.
Most of the existing boats came with plentiful spare parts, including an extra wing. The Artemis AC50 required major
reworking as her wetbox arrangement was entirely different from Oracle’s while the British AC50 had had extensive repairs (that needed replacing) carried out after her flying port hull landed on SoftBank Team Japan during day one of the quali- fiers in Bermuda.
Like the AC50s, the F50s remain demountable and come with removable bows and sterns. This was so they can fit into a standard 40ft container for shipping, but also so the bows and sterns could be quickly replaced as they were deemed the most vulnerable parts of the boat; although as Mike Drummond, who took over after Holroyd moved on to Ineos, observes, ‘That’s not how it turned out in Bermuda.’ In fact, Coutts was one of the pioneers in optimising racing yachts for easy trans- portation: he conceived the RC44 one- design, which remains the best 40-some- thing foot monohull to – most elegantly – be shoehorned into a standard container. For the first season the F50s will use the original AC50 wings. Under the original class rule the basic geometry of these were all identical. Variations were in their engi- neering and control systems, says Mike Drummond: ‘The teams came up with different designs for the control systems for camber and twist. Some flaps are stiffer than others, but they also have greater forces actuating the twist of the flaps. Therefore, you won’t be able to mix and match flaps between the current wings because the control systems won’t all be able to power them properly.’
Nonetheless they have equalised the wings as far as possible, says Holroyd: ‘A significant amount of tuning work was
INGRID ABERY
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