Cup Spy Nov 14: Emirates Team New Zealand flip their fortunes
by Richard Gladwell/Sail-World NZ 15 Nov 2023 18:26 NZDT
14 November 2023
Emirates Team New Zealand - AC40 - Day 42 - Auckland - November 14, 2023 © Sam Thom/America's Cup
Commentary:
Emirates Team New Zealand bounced back on Tuesday with an invaluable speed testing session - in a seastate that bordered on marginal value for the AC40.
Monday's issue on the port wingfoil appeared to have been fixed, and there was no sign of any recurring issues today.
Grey overcast skies replaced Monday's clear blue skies and bright sunshine. The breeze swung from SW to NE (offshore to onshore - for those who don't know Auckland).
In contrast to Monday, Tuesday's session had little downtime, with the Kiwi team running quickly through their test script - as normal.
With assistance of 14 power stabilized Fujinon binoculars, Cup Spy watched most of the session from the cliffs bordering the training area - between Course B and A - for the 2021 America's Cup. The clarity was amazing - no haze and no rain.
In a sunny day, this day would have been labeled "the famous Takapuna sea-breeze".
Today, without the sunshine picking out the whitecaps, this was merely a good testing breeze of about 10-17kts.
From the cliff edge we could see plenty of breaking waves - aggravated in some area by a wind against the outgoing tide - a sea state between 3-4 on the Beaufort scale - a good description of the breeze, too. These don't show in the Recon Team photos, with the camera doing its usual trick of flattening the sea-state.
The purpose of the day was, we guess, to test the newer port wingfoil against the older design of the starboard wingfoil. The latter is unusual in that it tapers down at its inboard end and up at its outer end. The new foil is more conventional.
A day like this requires skillful and consistent helming, so the data is as accurate as possible.
From our vantagepoint the tests consisted of a series of sausage shaped windward and leeward laps, off Wrecks Bay - getting some good data and images for the design and performance teams who watched online from the team base. Up and down, Up and down, Up and Down - until everyone's happy with the data and video collection.
While the AC37 Joint Recon team report claims that the new port foil is faster than its sister starboard foils, it was difficult to pick a gain from our vantage point. The only way to pick a speed difference is by pacing the target boat in a RIB with an accurate speedo. If the AC37 Recon crew did this and their measurement was accurate then the Kiwis may be onto a breakthrough. The trick of course, is whether it provides enough lift at the bottom end of the wind range (6.5kts) to get the AC75 lifted clear of the water, and start foiling as the apparent wind increases three or four fold.
In the seaway, the Kiwis also seemed to be playing with different fore and aft trim, which was probably getting close to the practical top end for the AC40s given what we have seen in Barcelona over the past few weeks.
By keeping the fore and after trim level, the chances of the rudder elevator breaking free as it passed through the hollow in a swell, are reduced, as more of the rudder and its attached elevator are immersed.
Towards the end of the session, the seastate seemed to ease a bit with the turning of the tie, and the Emirates Team NZ crew adopted a more conventional bow down position, with the forefoot very close to the surface - looking aft there seemed to be an awful lot of rudder blade exposed.
AC37 Joint Recon Team Reports:
Emirates Team New Zealand- AC40/LEQ12 - Day 42 - November 14, 2023 - Auckland
Day 42 for Emirates Team New Zealand on the LEQ 12 proved to be slightly different conditions to the sunshine and clear skies of the last couple of weeks.
Today was gloomy, overcast and with the promise of showers at some point throughout the day. Breeze was up and down as rain cells passed close by to the west, seeing as little as 9 knots and as much as 17 out on the training area.
After docking out at midday as planned, sails were hoisted and the team was sailing by 12:20. M2 and J2 were the sails used for the entire session. The team began the sailing session with a few manoeuvres off the Viaduct harbour and Yacht Squadron just below the harbour bridge.
After some control issues yesterday on the foils, the team seemed eager to load up the boat and check everything was working well, which it was. After a small session here, the team blasted down the harbour and headed out around North Head and based most of today’s training up between Rangitoto Lighthouse and A Buoy at the end of the shipping channel.
The boat was looking smooth, and even with the increasing sea state of up to 0.4m, the team were locked in. Running some decent height and windward heel on the up winds, and really pushing the ride height downwind, the boat looked fast. It seemed noticeably faster on starboard upwind on the new foil especially with the extra breeze around 13 – 15knots we were seeing at the time. The team were sailing in quite a small zone which forced a lot of manoeuvres. They were using marker buoys where possible to practice mark roundings, and even did a quick practice start at one point.
Over 25 tacks and 18 gybes were recorded today, and many high speed round ups and bear aways were seen as well. Eventually the sea state became a little too big next to Rangitoto, so the team set up to do some more testing near North Head off Cheltenham Beach in flatter water. The boat came to a stop and the chase boat came alongside. Peter Burling jumped onto the chase boat and Josh Junior, an Olympic Finn Sailor, took his place.
The team carried on with a very similar format of training, short up and down winds including lots of tacks and gybes. Here we saw another slight build in the average wind speed, and were seeing 15-17 knots at times.
At 1407hrs the team left this training area and headed toward home. Sails were dropped at 1415 and the team were back on the dock just after 1430hrs.
The yacht was lifted out by 1500hrs and the team went back into the shed looking content with the short, but sweet, session of the day.
We managed to grab Peter Burling, one of Emirates TNZ's Helmsman for the interview today to try and give us an insight into the direction of the testing today and going forward.
Crew: Peter Burling, Nathan Outteridge, Andy Maloney, Blair Tuke and Josh Junior (replacing Peter Burling, mid session).
Session Statistics: Emirates Team New Zealand- AC40/LEQ12 - Day 42 - November 14, 2023 - Auckland
- Weather: Cloudy, overcast 16°C cloudy
- Wind Strength 9-17kts
- Wind Direction: 340° - 020°
- Sea State: Beaufort 3-4
- Crane In: 1140hrs Dock Out: 1200hrs
- Dock In: 1430hrs Crane out: 1500kts
- Total Tacks: 47 - Fully foiling: 46; Touch & Go: 1; Touch Down: 1
- Total Gybes: 41 - Fully foiling: 39; Touch & Go: 1; Touch Down: 1