Engineering the AC45

Gilles Martin-Raget / Oracle Racing
Multihull enthusiast and Oracle Racing chief engineer Dirk Kramers on the AC45
A man very much enjoying the America’s Cup shift to catamarans is Oracle Racing’s structural engineering guru Dirk Kramers, a multihull fan who over past decades has been particularly involved in the A-Class. With Cup involvement dating back to the 12m era and having worked for Alinghi for the past three AC, including the Alinghi 5 maxi-catamaran, Kramers was snatched up by Oracle on the demise of the Swiss team, along with Murray Jones, CAD expert Aaron Perry, mast designer/engineer Kirst Feddersen and bowman Piet van Nieuwenhuyzen. Since joining the team Kramers has been working out of an office close to home in Newport, with other Rhode Island-based Oracle design team members, Perry and mast specialists Scott Ferguson and Andrew Gaynor. He expects sometime later this year to decamp to San Francisco, when Oracle Racing set up their new team base at the AC34 venue. While Kramers’ speciality is engineering, his long term interest in multihulls as both a sailor and a designer allow him to hold a comprehensive perspective on the latest boat developments in Cup land, and the most recent addition, the AC45. “All multihull shapes are starting to gravitate to this kind of shape, all the way from A-classes to F18s, to M2s on the Swiss lakes - they are all starting to look very similar,” says Kramers of the AC45 hulls, Where there is noticeable difference is in the bow profile. The Extreme 40 for example has plumb bows where the latest trend Kramers describes is for reverse ‘Dreadnought’ wavepiercing-style bows which you are seeing now from everything from Banque Populaire to USA 17 down to A-cats and F18s. “It is visually probably the most striking difference, but there is a lot more to it than just kicking the bow back,” says Kramers of the bow profile. “There’s volume distribution, how