Please select your home edition
Edition
Rooster 2020 - Impact BA - LEADERBOARD

America's Cup Rialto: August 1 - what we've seen in the first week in Auckland

by Richard Gladwell/Sail-World.com/NZ 1 Aug 2020 04:28 PDT 30 July 2020
American Magic - Waitemata Harbour - Auckland - America's Cup 36 - July 28, 2020 © Richard Gladwell, Sail-World.com / nz

America's Cup Rialto is a new series for the 36th America's Cup, and will publish each day an Americas's Cup boat sails - with images of the day. Usually there will be a morning report (NZT) based on when the boats have passed North Head - when there is usually the best photo opportunity.

Strong winds are lashing the Auckland area, and there was no sailing Friday, Saturday and Sunday.

Monday to Friday of the coming week should be moderate to fresh winds - all from an easterly direction.

American Magic sailed their AC75, Defiant, on three days of the four available, last week. Emirates Team New Zealand, with a choice of an AC75 or a test boat opted to sail only their 12 metre long test boat Te Kahu. We have not yet had the opportunity to see boat AC75's side by side. However we can now go back through previous images in similar locations of the two AC75's and get some idea of their relative strengths and issues.

Te Aihe has a skiff concept complete with a centreline bustle. Defiant is at the other extreme with a scow type hull notable for its shallow underbody, with no bustle. In fact Defiant is now the only AC75 without a bustle - now that the British have retrofitted a similar device within the limitations of the 12.5% hull surface area modification permitted by the AC75 class rule. Luna Rossa launched with a bustle, as did ETNZ's Te Aihe.

Both teams, in Auckland, have perfected the technique of being able to sail to windward with the hulls very close to the water without making contact with the surface. (We presume this is also the case with other teams.) The bow-on view of Defiant is notable for both the low flight height, and what happens when the underside of the hull does appear to make contact with the water. Generally contact appears to be very minimal, causes no spray to be flicked up, unless it is a serious closure with the surface, in which case the displaced water appears to shoot sideways, and gets picked up in the foil spray.

At times, Defiant seems to be throwing a lot of water from her immersed (leeward) foil in winds at the lighter end of the scale. It appears that her ability to foil at the lower end of the wind range is not as good as we have seen on Te Aihe.

Further up the wind scale, there appears to be little difference in this regard between the two AC75's (Te Aihe and Defiant). We can't estimate speed from the shore, and speed guns are not reliable at more than 500metres distant.

In foiling conditions (winds above 7kts) Te Aihe is quick to foil - taking less than a couple of seconds to get foil borne. From what we have seen of Defiant she appears to take five seconds or more to get on her foils, and usually does this by starting very bow up, and with a lot of water being thrown about in the area of the foil arms.

Once she is foil borne Defiant doesn't appear to have too many issues staying in the air, and presents what appears to be a very efficient aerodynamic profile - bow down and slightly heeled to windward. She seems to be able to carry this stance up and downwind.

It is not clear why Defiant appears to be bow-up, when she exits from a tack that is not a dry tack. In the AC75 Class rule the rudder is permitted under control to move fore and aft (rake) and sideways (yaw)

It also must be remembered that in all these images and tests, they are just that - images from test programs. They are not a definitive record of whether one boat will always be slower or faster than the other. Plus one of the test practices is to test a configuration which may be optimal in heavy air, for instance, and would be expected to exhibit some serious downsides in light air. And then of course, as we saw with ETNZ's light air daggerboards in the last Cup, the trick is to extend the range of the preferred board beyond its optimum.

For the 36th America's Cup the competitors are only permitted to use one set of foils per round, which must be declared two days before the start of that round. In the last Cup they could be changed daily - depending on the forecast. As a consequence "All Purpose" wings and flap systems must be used

Of course, Defiant has not sailed for five months and it would be expected that her performance would not be as slick, as had they been sailing solidly (five weeks of lockdown aside) as the Kiwis.

From the amount of time taken during the time outs which have punctuated Defiant's test sessions, our guess is that they have proceeded to try new developments/gear - instead of just sailing the boat in the same design configuration as she was in Florida.

The occasion of Te Aihe and Defiant being on the same patch of water will be of great interest, and the comparison will be continued.

Related Articles

America's Cup: Defender rebuffs NYYC overtures
The America's Cup Defenders and Challenger of Record have rebuffed NYYC's Challenge Unsurprisingly, the America's Cup Defenders, along with the Challenger of Record, have rebuffed the surprise Challenge lodged by the New York Yacht Club, on May 6, and announced earlier today. Posted on 9 May
Gladwell's Line: Pressing ignition on pro-sailing
The sail racing world is spluttering back into life after over 12 months of being hostage by COVID The sail racing world is spluttering back into life after over 12 months of being hostage to the COVID pandemic - here's a look at how SailGP and the America's Cup coped, plus the 2024 Olympic event quandary. Posted on 6 May
American Magic ready to sail with 7-8 days notice
American Magic's Terry Hutchinson says they are all ready to go sailing at 7-8 days notice American Magic's Terry Hutchinson says the AC36 Challenger are all packed and ready to go sailing at 7-8 days notice, if the next venue is Auckland, otherwise they will head back to the USA. Posted on 3 May
SailGP Bermuda: Dramatic onboard collision video
Dramatic video footage shot from on-board Japan SailGP as their courses intersected with USA SailGP Dramatic video footage shot from on-board Japan SailGP as their courses intersected with USA SailGP on Leg 3 of Race 4 of Day 2 of SailGP Bermuda. Nathan Outteridge describes how it unfolded. Posted on 26 Apr
ACHof: Induction of Peter Montgomery and Ed Baird
America's Cup Hall of Fame: Induction of Peter Montgomery and Ed Baird On March 19, 2021, just a couple of days after the Emirates Team New Zealand successfully defended the America's Cup, the America's Cup Hall of Fame held an Induction Ceremony to welcome broadcaster PJ Montgomery and America's Cup winner Ed Baird Posted on 22 Apr
America's Cup: Luna Rossa's control systems outed
AC36 Challenger Luna Rossa explain how their systems work and the rules that govern their use Handling a boat like the AC75 requires the use of sophisticated management and control systems actioning a compact network of valves and pistons. Here Luna Rossa explain how their systems work and the rules that govern their use Posted on 14 Apr
Coutts more confident of SailGP Bermuda proceeding
SailGP needs COVID dispensations for Bermuda event to proceed on schedule Russell Coutts, CEO of SailGP has told Bermuda Tonight that he is more confident of the first regatta in the 2021 circuit getting underway as scheduled, despite there being only 10 days left until the scheduled start on April 24. Posted on 14 Apr
SailGP: Bermuda goes into seven day lockdown
Bermuda will enter a "shelter at home" policy, ending after the start of SailGP Round 2 It has been announced in Bermuda that the island will enter a "shelter at home" policy for the next seven days at least. The Premier says no exceptions will be made for SailGP for training or racing. Posted on 12 Apr
36th America's Cup put under the microscope
The international broadcast team for 36AC give their take on the breakpoints of regatta Key moments and analysis on the 36th America's Cup. This includes several interviews with key team members on their recollections of some of the more spectacular incidents, which were glossed over at the time due to the pace of the event. Posted on 10 Apr
America's Cup: Gulf Wars - your record of 36AC
A souvenir record of the regattas of the 36th America's Cup is now on sale across all regions A souvenir record of the regattas of the 36th America's Cup is now on sale in New Zealand, and available internationally published just over a week after racing concluded in the 36th America's Cup. Posted on 31 Mar
RS Sailing 2021 - FOOTERHella Dual Colour Floodlights - 728 x 90px - 1 jpg BottomHighfield Boats - SW - FOOTER