Submitted by Hal Nauman
As is prescribed within the America’s Cup racing program, the country
currently holding the AC cup gets to pick what kind of boat will be raced
in the next event. New Zealand won the America’s Cup in 2017 and the
new AC75s are what they cooked up for the 36 th America’s Cup event
scheduled to be held in Auckland March 2021. When the concept of the
new AC75 was released late 2017, reactions ranged from “ambitious to
wacky”. Indeed, the concept looks like it just came from a “Men in Black”
casting call.
However, the AC75 design seems to be fairly straight forward and
appears to be working. The vessels are mono hull hot rods (how about
that!) that have been stretched out to 75 feet with no keels or center
boards. Stability comes from port and starboard ballasted foils that are
cantilevered and work similarly to a tight rope walker’s pole. The
concept looks disconcerting but this writer thinks it will work in the
narrow venue of high performance match racing.
The new AC75s have many of the advantages of both multi and a mono
hulls. The main point is that these mono hulls can easily get clear of the
water on bilateral RHIB killing foils. Mono hulls are attractive because
they are easier to build, maintain, and store than a gargantuan
catamaran.
The advantages go on to include that these long skinny legged girls are
self righting and probably not as inclined to pitch pole as the truly
magnificent catamarans seemed to be. The new AC75s appear to be able
accelerate and maneuver with more alacrity than the big cats.
It is hard to imagine these hot rods making the jump to club or regatta
racing. The builder reports that the boats are fast but are very difficult to
sail. Also, there are bound to be damaged boats or injured crew in a cluttered fleet of club racers once the weaponized foils are deployed. Toby would have to work inside a stainless steel cadge. Stability is simply acquired; hang the weather foil in the air to keep a boat upright and sink the leeward foil to keep a boat attached to the water. Sink both foils and a boat will act like a standard keel boat. Any guesses how the AC75s tolerates offshore exposed heavy weather?