America's Cup Rialto: New York launches second AC75
by Richard Gladwell Sail-World NZ 16 Oct 2020 10:55 UTC
15 October 2020
Patriot - American Magic - launching October 16, 2020, America's Cup 36, Auckland © Richard Gladwell / Sail-World.com
Patriot, the first of the second generation AC75's was launched from the American Magic base, in Auckland, around 9.00am local time.
Instead of being a development of what had gone before, the Marcelino Botin led American Magic design team came up with a design which is quite different.
The only similarity to any of the four AC75's previously launched is the small skeg running down the centre of the underside of the hull. That feature was first seen on Italian Challenger Luna Rossa, but on Patriot, as the New York Yacht Club entry has been named, the skeg is a much less significant part of the hull than on the Italian boat.
The most obvious feature on the boat is the flared bow, unusual for a yacht, and it will be interesting to see how it works in action. Emirates Team New Zealand was the first to launch with a bustle running its full length, and the concept does seem to provide a leg-up if the boat drops off the foils, or needs a bit of buoyancy/hull volume to get onto its foils. But Patriot is quite different and there is not a lot of volume in the skeg. From the foil-trial video it seems as though forward section of the hull itself, will do any heavy lifting required.
Botin describes the hull shape as "being a continuation of the rig and the sail plan. What you are trying to achieve with the hull is to maximise the driving force of the rig and sail plan and minimise the heeling moment. It's as simple or complicated as that', he adds.
"We have a very interesting platform to start working with."
As for the flared bow Botin says again that is "just maximising driving force and minimising heeling. The bow shape and indeed the whole boat is guided towards that one objective."
The hull is very deceptive, and seems to change depending on the viewing perspective. Looking forward from the stern quarter the eye is drawn to the flare in the bow, which in profile appears to almost be a clipper bow. Looked at from the reciprocal direction the bow looks to be a completely different shape - with no flare, and the bow sections appear to be flat - and the hull shape generally appears to be very simple, refined and easy on the eye.
The transom and stern sections are very shallow and almost dinghy like, and the centre line skeg becomes so fine that it gets lost before it reaches the stern.
Of course the key point is that if the hull of an AC75 is in the water, then it is not going to be winning races. It was apparent from watching Emirates Team New Zealand's Te Aihe sail over the past two or three weeks that it is quite possible to sail several legs without the hull making contact with the surface of the water. And like with the AC50's the AC75's will have to sail dry laps.
While it may not have always been caught on the TV camera, on the water in Bermuda it was obvious that a competitor doing anything other than a soft and fleeting touchdown was dropping margin on their opponent. That was time they could only get back by getting out of phase with the race leader and getting a lift, or more pressure, or both.
The AC75's from what we've seen don't look to be a whole lot different.
From the video of the towing test on Friday afternoon, the Patriot design package becomes more clear - with the hull riding bow down for reduced windage, and forward section of the the underside of the hull sitting just clear of the water, and hopefully able to lift the hull back into proper trim if it does make contact with the surface.
Above the waterline, Patriot looks to be a very interesting design. The deck height peaks at the base of the mast and drops down to the bow and almost right away at the transom.
There are two crew trenches either side which are an elongated teardrop shape and well defined. Botin and his design team have gone away from the open cockpit layout of Defiant.
The trenches look to be deep with two winch grinding stations in each trench ahead of the steering position. The crew should be well protected in the event of a sudden nosedive, or some similar excitement. That was certainly the case on their first ever sail when the AC75 performed like a frisky dolphin, leaping clear of the water as a result of a foil control system snafu, before diving bow first into the Waitemata Harbour.
It would seem that like on Te Aihe two or three of the crew will cross the boat after each tack or gybe, and there is a big area of non-skid fore and aft of the mainsheet traveller.
Sailing trials are expected to start in earnest early next week.