What's hidden under BMW Oracle skirt?

by Sail-World/GJN on 1 Apr 2006 BMW Oracle Racing put America's Cup aficionados in uproar when they launched their new AC boat, USA87. The teams are now able to hide their hulls with a skirt and this allowed BMW Oracle Racing to reveal only the merest glimpse of their new boat - the new bowsprit.

This revelation has lead to considerable discussion on just what this was to achieve. But then attention switched to what they hadn't revealed, the keel. It was noticed that the mast was some two metres further forward than the previous boats and the forestay was now closer to the bow, less then a metre. This could indicate that the overall length is less and according to Peter Islar USA 87 is shorter but with the bowsprit the same length.

So what is going on?

According to an article by Tim Jefferies in the Daily Telegraph, Thursday - Chris Dickson, chief executive and skipper of BMW Oracle Racing, knows his America's Cup rivals are convinced that the new USA 87 has a radical keel configuration.

'They know as of a week ago what we've done,' he says. The word in Valencia is that a member of Italy's Luna Rossa caught a glimpse of a rudderless twin keel soon after USA 87 was flown in from Washington State where it was built.

'This boat is not a refinement of something we've done before, it's a big leap in many areas,' says Dickson, neither confirming nor denying talk of an unusual keel.

But....

Ben Chertoff in his web blog on 28 March thought that Oracle were playing a slight of hand here and quoted American tactician Peter Isler - 'We want everybody looking at that the bowsprit.' and 'Every pound you save in the boat is just another pound we can put on the keel bulb.'

Chertoff further posted, on Friday 30 March, after seeing USA87 sailing with USA76 - 'the distance from the mast to the forestay (or 'j') is unchanged, as is the distance from the mast to the stern. So the shortened bow means a shortened boat, with the small bow sprit making up the distance. (And, contrary to one commentor's suggestion, it is structural, serving as a fairlead attachment for the foreguy/tackline.)'

Interesting that in a comment posted to Chertoff's blog, Bruce Kirby noted -

'Under the skirt I think we will find a hull with a very hard turn to the bilge (the AC boats have been moving in this direction) and quite a flat bottom. Oracle's next boat will probably take this design feature even further and look like an elongated Starboat with a hard chine and a flat arc to the bottom. -- Bruce Kirby, brucekirbymarine.com '

Time will tell but in the meantime the blogs will fly....

Background Links:

Benjamin Chertoff: http://www.popularmechanics.com/blog/outdoors/2552506.html

Tim Jefferies: http://www.telegraph.co.uk/sport/main.jhtml?xml=/sport/2006/03/29/sosail29.xml&sSheet=/sport/2006/03/29/ixothspt.html

Bruce Kirby: http://www.brucekirbymarine.com