America's Cup: Images and analysis of INEOS Team UK's first AC75
by Shaun Roster/Richard Gladwell/Sail-World.com/nz 4 Oct 2019 20:15 BST
5 October 2019
First AC75 launch - INEOS Team UK - Portsmouth, UK - October 4, 2019 © Shaun Roster
The British America's Cup team INEOS Team UK was the last of the four "Super teams" in the 36th America's Cup to launch their AC75, which was splashed on Friday, UK time at Portsmouth.
Photographer Shaun Roster of www.shaunroster.com was on hand to catch these images from the launch.
The British hull shape is the most radical approach seen yet of the four teams, however when broken down into its basic elements it is possible to see past the distracting feature of the bow/nose shape and see the way the other elements may be intended to work.
Probably best described as a design of two halves, the section of the hull forward of the jib tracks is low profile presumably with a focus on aero-drag reduction. The after half is dominated by the crew trenches, and high slab sided topsides
Most obvious feature of the hull shape is the slab sides, without any real attempt to get extra beam as have the other three teams.
(There is no beam measurement on the AC75. The beam is effectively limited by the rule which requires the pivot points for the carbon foil arms to be 2050mm from the centreline giving a total "beam" of 4100mm between the two foil pivot points. The AC75 can be wider, but the pivot points or "Foil Cant Axis" cannot be wider than 4100mm.)
Britannia lacks the dimple of others around the carbon foil arm to permit the foil arm to be fully raised and lowered without making contact with the hull - however she does appear to have a sharper recess to accommodate the upper range of the carbon foil rotation.
While the other three first launches have a sheerline which tapers towards the transom, Britannia has a more complex approach with high topsides running on the outside the the crew trench. Between the two trenches the centre deck slopes into the transom providing an end plate for the decksweeper mainsail, when this is fitted.
The photos of the bow are deceptive, probably caused by lens distortion. Other shots show a more rounded bow quarter, rolling up into the centreline.
The deck layout in the bow area is the most extreme treatment yet with the recessed foredeck approach, presumably to help tidy up airflows around the foot of the jib, rather than just accepting the decksweeper jib solution of the other three teams. The foredeck (forward of the jib tracks) slopes down to about half the expected bow height
The crew cockpits are tight, with two grinding pedestals forward of the helm position and two aft.
The underside of the hull is a similar approach to NYYC American Magic with quite a shallow almost scow like approach, and a very clean uncomplicated shape - unlike Emirates Team New Zealand and Luna Rossa.
The bow is a similar but more radical treatment than NYYC American Magic presumably for improved aerodynamics and to work airflows around the point where the sails meet the deck.
INEOS Team UK have gone for a similar design approach to Emirates Team New Zealand with their wings.
They have opted for a longer, narrower chord wing than the other Italian or New York Challenges. They have a relatively small ballast torpedo/bulb. A feature of the wings are small "spoilers" to keep the flows over the wings aligned and prevent "cross wash" which would reduce the wings effectiveness.
"Britannia" rounds out the first launch cycle with Emirates Team New Zealand and American Magic launching in the first week of September. Luna Rossa Prada Pirelli and INEOS Team UK both launched in the first week of October, almost a month later.
The fourth Challenger, Starts + Stripes Team USA are expected to launch their race boat late this year, and it is expected to be to the same base design as that launched by Emirates Team New Zealand.
Luna Rossa and Britannia are expected to go through the now usual routine of testing foil systems under tow before sailing in a few days time.