COMMENT: By Richard Gladwell, Sail-World.com/nz
August 29 will mark two years since the AC75 foiling monohull concept was announced at the Royal New Zealand Yacht Squadron, after six months of development work to create a state of the art, new class of racing yacht for the event.
And, with September 6 marking 12 months since the first AC75's were launched, the first two teams to launch AC75's are the same two who were the first to set up in Auckland, and are now preparing for the 2021 America's Cup.
The AC75 concept took many by surprise, and the predictions were dire as to its suitability and safety for racing in the America's Cup.
Interestingly, the heads of both Emirates Team New Zealand and American Magic were dismissive of the images shot last Monday of the US Challenger Defiant appearing to heel to an extreme angle, and heading for a capsize. "Heeled over a bit, but did not feel risky", was AM's skipper Terry Hutchinson's reaction. "Doesn't look too bad", was ETNZ's Grant Dalton take on the same shot.
Despite the dire predictions, mostly from those who have never seen an AC75 sailing first hand, the radical class has defied its critics.
So far there has been one capsize, a couple of "sky jumps" where the 75ft foiler impressively leaps completely clear of the water, a dismasting, and a broken bobstay. The latter incident led to a section of the bow and deck being ripped from the hull of the Italian boat.
At the time of the announcement of the AC75, there was a degree of scepticism as to whether the boat would self-right. That proved to be justified in the single incidence of a capsize.
The righting of Team New Zealand's capsized AC75 on the week before Christmas took just four and a half minutes, using chase boats, and the boat continued with a three-hour sailing session soon after being righted. That's comparable with a racing dinghy capsizing in a race, and had there been a second race in the day, Te Aihe would have been able to compete.
It compares very favourably with Team New Zealand's previous capsize incident in their AC50 in Bermuda. While AC50's had tipped over in training and had been righted, the Kiwi's nosedive on the start line on Day 2 of the semifinals was a lot more serious. It took an expert team 40 minutes to right the wingsailed catamaran, and as long again to "sideslip" the boat back to base in the Royal Dockyard.
The AC50 was back in sailing condition by the next day - when racing was fortuitously cancelled - and it took another day/night of supreme effort by the shore team to put it back into race-winning condition.
Looking back at the previous classes used in the America's Cup, there were 100 of the International America's Cup Class of 83ft (25mtr) keelboats built for use in the 1992-2007 America's Cups. One broke in half and sank. Another broke in half, after structural failure in the deck, but was retrieved. Another lost its keel and capsized.
The 120ft multihulls used in the 2010 America's Cup commonly raced with a cacophony of strain gauge alarms sounding but suffered no damage in the two races they sailed.
Of the seven AC72 wingsailed catamarans built for the 2013 America's Cup, there were two catastrophic failures, with one crew member being killed. Team New Zealand narrowly avoided a nosedive which washed two crew members overboard and later avoided a capsize by the narrowest of margins.
The AC75 has been the most spectacular of the four America's Cup classes used during the past 30 years.
In the hands of expert crews, trained on simulators, the AC75 seems to be performing as expected.
Their most vulnerable point of sail seems to be emerging from a high-speed gybe - where the boat completes the manoeuvre without incident. But a few seconds later the sailing physics get scrambled, causing the rudder wing to lose its lift. That has marked effect on hull trim angle with the bow lifting up altering the main foils to an extreme angle with the AC75 is still sailing at speed - and the 7.5 tonne AC75 lifts off.
In Luna Rossa's case, the AC75 landed on its topside and came upright. Team New Zealand wasn't so fortunate and skidded sideways before capsizing onto her side, with her mast lying near flat in a perfect recovery position.
If the capsized AC75 floated any higher the windage on the over-buoyant hull would cause the boat to continue to roll over and invert. At 26.5m long the AC75 mast would quickly impale itself in the mud at the bottom of the 12.5mtrs deep dredged Rangitoto Channel, and less elsewhere.
We can expect to see the second boats for the three Challengers to be revealed next month.
American Magic confirmed to the Herald that their second AC75 is nearing completion at the team's production facility in historic Bristol, Rhode Island. The AC75 will be airlifted to New Zealand in September and will be commissioned at the team's base in Auckland.
Images have emerged in the last couple of days of INEOS Team UK's second AC75 being barged to the team's base in Portsmouth UK. The team confirmed to the Herald that they had started to relocate to New Zealand and that their AC75 will be flown to New Zealand in September, with their first launched shipped to Auckland.
Luna Rossa Prada Pirelli's base is under construction on the Hobson Wharf extension, and the team are expected to arrive at the end of September and be sailing on October 20.