Cup Spy July 19: A Game of Threes
by Richard Gladwell/Sail-World NZ 20 Jul 2023 07:08 PDT
20 July 2023
Emirates Team New Zealand - AC75 - Day 24 - July 19, 2023 - Barcelona © Job Vermeulen / America's Cup
Three teams conducted testing today, using three different types of test boat, and with three different strategies.
Two of the teams tested foils using different methods, in 40fters. The third (ETNZ) tested light air capability in their AC75.
What happened in the Cup - July 19, 2023:
- Alinghi Red Bull Racing sailed their two AC40's put into One Design mode, with the One Design rigs being fitted to both boats, and One Design foils on one boat, with the other carrying a One Design foil on port side and the latest test foil on the other. The objective of the day was to properly evaluate the test foil. The one design foil was designed by Emirates Team NZ as part of the AC40 One Design package and is a good benchmark according to the team.
- Luna Rossa - sailed out of Cagliari in their custom design LEQ12 in winds of 9-13kts and temperatures of 39°C. They tested two of their prototype wing foils on the LEQ12. Their AC40 One Design is located in Barcelona.
- Emirates Team New Zealand sailed their AC75, which is the current America's Cup champion, upgraded to Version 2 of the AC75 Class Rule. The team sailed in wind measured by the AC37 Recon Team at between 1.5 - 3kts at 8ft above the surface. The Recon Team noted that ETNZ were pumping the mainsail using he traveller, and in their estimation the AC75 could get foiling without tow assistance in a 2.5kts windstrength or above, and at 2.0kts they needed tow assistance from their Chase Boat.
- American Magic - did not sail.
- INEOS Britannia will not be sailing until August 1, and are transiting to Barcelona from their pre-Cup base in Mallorca.
- No further news from the Orient Express Team (formerly K-Challenge).
Commentary:
This is one of the few America's Cup where prototype yachts have been used/permitted.
First time they were used was in the 2013 America's Cup where the AC45 wingsailed class was created, and again in 2017, when prototypes were permitted, provided they used AC45 hulls. For the 2021 America's Cup, the teams were permitted to build two AC75's or prototypes of less than 12metres in length.
The teams now have several options of test boats provided they are under 12metres in length, or using recycled AC75s from the previous America's Cup. These can only be altered from above the sheerline (allowing different cockpit configurations to be tested).
The issue with all the prototype approaches, is that there is certainty as to the scalability of a 12metre boat to one that is 21 metres long.
The results are at best indicative, and sit alongside the computer based performance modelling - providing that is accurate.
It is therefore a little surprising that, at this stage, more teams are not running AC75s as test boats.
On the time scale of sign-off - with boat design being the first, wing foils are probably second - due to the time required for evaluation and manufacture.
Alinghi Red Bull Racing has probably taken the most extreme approach, exemplified by their "Tubercle" foil. But today were testing a more conventional foil against the One Design foil. That is not to forget that their design team is led by Marcelino Botin, formerly head of the American Magic design program for the 2021 America's Cup - and on their AC75 they have tested legacy foils from the American Magic and Emirates Team New Zealand programs (both of which used minimum area foils). The Swiss put up sail trimmer Lucien Crujen up for the permitted three minute interview at the end of each session by the AC37 Joint Recon Team.
He wasn't giving away too much, except that they regarded the AC40 One Design foil as being a good benchmark to evaluate the performance data from their other foil design options.
The AC37 Recon Team tried unsuccessfully to get Crujen to confirm their off the boat view, that the "Yellow" boat with the development foil fitted was making less leeway that the "Red" boat fitted with One Design foils.
Horatio Carabelli, design co-ordinator for Luna Rossa Prada Pirelli confirmed that the design focus was "all about the foils at the moment, and we're concentrating quite a bit of in that area." He said the Italian team were "now at the end, we only have one more card to play. And we're pretty happy with our development and what we are achieving." That is a reference to the number of foil designs that the team is allowed to test on its prototype boat - and that the Italians only have one more left, if they chose to use it.
Peer Burling co-helmsman of Emirates Team New Zealand confirmed that the objective of this short test-block was to check the performance of their AC75 across the wind range. And they'd achieved that - and the data gathered in Barcelona will now be checked against the results of their testing in Auckland, and also checked against their various performance simulators and prediction software.
"Today we were right at the bottom of the wind strength," Burling told the AC37 Joint Recon Team, "and now we just got enough [wind] to foil in on the course area, which was pretty nice. As a team we have now have five days sailing in this little block, with a good range of windstrengths - that we think we're probably going to end up spending a lot of time in [during the Cup] and just trying to get comfortable across the board."
From the videos and images we can see the AC75 being sailed with very precise flight control, and with the hull creating a solid endplate between the rig and the water surface for maximum rig efficiency.
In the upgrade of the AC75 since that last Cup, the drag reduction is one of the most notable changes. However it is surprising that the AC75 can foil, and do so on its own power in winds as light as those claimed - bearing in mind the take-off speed is probably around 16kts. In one of its last sails in Auckland, for which we were on board the chase boat, the AC75 really struggled in a 3-5kt breeze, and was towed up to get sailing on its own apparent wind. That would indicate that there is maybe significant variation in wind strength in Valencia - even at mid-rig height, and that is what is powering the AC75 in these apparently light conditions.
The other factor is that none of the testing is being done under race pressure - where crews do make mistakes, where you are forced to tack/gybe for tactical reasons - not the optimum position in testing. And the time taken to recover once an AC75 has fallen off its foils is a significant factor in deciding race outcomes.
Weather conditions at Barcelona July 19, 2023:
On the water the one AC37 Recon teams reported lower strength breezes than the onshore weather station at the entrance to Port Olimpic.
The Alinghi RBR Recon teams quoted a reading of around 7-12kts from 150 degrees-180 degrees. The ETNZ Recon team recorded 1.5-3.0kts from 150 degrees - 175 degrees.
At the real-time observation station at Port Olimpic the wind dropped to 5kts around 1230hrs and peaked at 9kts at 1545hrs. gusts were 6kts and 11kts respectively at those times. Winds stayed above 5kts until the 2000hrs and was mostly above 7kts.
Wind direction was in the mostly in the range of 165 degrees-195 degrees.
The difference between the on the water and weather station readings may be explained by the height difference - 2.5 metres for the AC37 Recon Teams and 12 metres for the Port Olimpic weather station. The mast height on an AC75 is 26.5 metres - so the Port Olimpic station is reading at about mid-rig height.
AC37 Joint Recon Team Reports:
Luna Rossa Prada Pirelli - LEQ12 - Day 77 - July 19, 2023 - Cagliari
Luna Rossa Prada Pirelli team rolled out their LEQ12 prototype at 12:00 on a record hottest day in Cagliari, the mast was quickly stepped at 1215hrs and the yacht was craned in.
Some ventilators and dehumidifiers have been installed on the boat allowing shore crew to work below deck in the 39 degreesC heat.
Before dockout scheduled for 1330hrs, the mainsail M1 was locked in the mast fittings. Once exited the harbour, the seabreeze was filling it slowly not exceeding 9kts from 175 degrees TWA [True Wind Angle]. The team seemed to struggle slightly to fully hoist the main which was then paired with the J1.5 by 1400hrs.
With six crew onboard, the first smooth self take off was observed after an initial pull by Chase-2, according to the GPS, the LEQ12 took off with 16-17kts at 85 degrees TWA.
Once up and foiling long straight line prevailed for mode testing within the first two foiling stints with a small number of maneuvers. A starting gate was laid out and the LEQ12 conducted six approximate pre-starts in a row without really entering the box two minutes beforehand.
On the following break some shore crew jumped on board and gathered with the sailors at the mast base and cockpit. Shortly after, the LEQ12 was up and foiling again picking up its pace on two legs around the race course before stopping at 1540hrs to lower the J1.5 as the breeze had increased to 11-13kts opting for the J2.
Several minutes of long straight line testing followed heading upwind towards Sarroch perhaps to get some flat water and to crosscheck the targets on both tacks before bearing away for an even longer downwind ride exceeding 40 kts.
Towards the end of the sailing day, two additional complete prestarts have been observed including four legs with some occasional interference by chase1. During this day a foiling time of 109 minutes, with 28 tacks, and 24 gybes were counted [Report from Michele Melis AC Recon].
Session Statistics: Luna Rossa Prada Pirelli - LEQ12 - Day 77 - July 19, 2023 - Cagliari
- Weather: Overcast 39 degreesC
- Wind Strength 9-13kts
- Wind Direction: 170 degrees
- Sea State: Light chop
- Crane In: 1215hrs Dock Out: 1330hrs
- Dock In: 1740hrs Crane out: 1820hrs
- Total Tacks: 28 - Fully foiling: 25; Touch & Go: 1; Touch Down: 2
- Total Gybes: 25 - Fully foiling: 21; Touch & Go: 3; Touch Down: 1
Crew: Francesco Bruni, Marco Gradoni, Umberto Molineris, Vittorio Bissaro, Ruggero Tita, Mattia Camboni (cyclor).
Emirates Team NZ - AC75 - Day 24 - July 19, 2023 - Barcelona
ETNZ rolled out their AC75 Te Rehutai from the shed at 1000hrs. The boat was craned to the water at 1038hrs and the team docked out at 1130hrs, as planned. Exact same timing as yesterday.
The M1 and the J1 were hoisted at 1145hrs being the only sails that were used today.
Today's training consisted of sailing in extremely light wind conditions, averaging 2.5kts of TWS [True Wind Speed] measured at sea level, focusing on the take-offs' and managing to continue to fly while tacking and gybing.
Crucial aspect: They were pumping the main all the time, non-stop, while sailing upwind, downwind and a bit harder maybe when coming out of the tacks and gybes to try to continue to fly and create power on the boat.
If Racing Rule 42 (Propulsion) had applied today and had there been a jury on the water, the Kiwis would have had collected lots of yellow flags. However, it was clear that in terms of performance it worked.
On the pumps, the tension on the leech and the amount of twist remained unchanged, constant, with full control. The entire main, even the top was pumping.
More probable that these pumps were performed with movements of the traveller rather than with the main sheet, due to the way in which the leech was moving.
ETNZ did approximately 13 tacks and 17 gybes with more than a 50% of them flying.
Over 3kts of TWS at sea level they had no problems, when it went down to 2.5kts of TWS it was when it started to get critical. Under 2kts of TWS they were touching down completely.
Consider those numbers while consistently pumping.
As regards the sailing conditions, the maximum wind speed recorded was 3,5 knots of TWS at sea level immediately after coming out of the port. Wind average for the day was 2,5 knots and it got lighter during the end of the training session to 1 knot. Direction 140 degrees-150 degrees shifting right during the day up to 160 degrees-165 degrees.
Completely flat water, clear skies with scattered high Ci clouds, and definitely hot.
Impressive performance from ETNZ in extremely light wind conditions. For sure we would not have had any races today if it were a racing day. [The minimum average windspeed required on a rolling boxcar basis is 6.5kts]
Sails were lowered at 1411hrs, the boat was docked at 1430hrs and put back in the shed at 1500hrs with no irregularities.
ETNZ will resume their training sessions from Tuesday next week.
Session Statistics - Emirates Team NZ - AC75 - Day 24 - July 19, 2023 - Barcelona
- Weather: Sunny 34 degreesC
- Wind Strength 1.5 - 3.0kts
- Wind Direction: 150 degrees-170 degrees
- Sea State: Flat
- Crane In: 1038hrs Dock Out: 1130hrs
- Dock In: 1430hrs Crane out: 1500hrs
- Total Tacks: 13 - Fully foiling: 7; Touch & Go: 2; Touch Down: 4
- Total Gybes: 17 - Fully foiling: 10; Touch & Go: 5; Touch Down: 2
Crew: Nathan Outteridge, Peter Burling, Andy Maloney, Blair Tuke.
Alinghi Red Bull Racing LEQ12 - Day 43 - July 19, 2023 - Barcelona
Alinghi Red Bull Racing rolled out their AC40-7 (Red) and AC40-4 (Yellow) at 0915hrs and 0950hrs respectively and prepared at the dock.
Attention was observed towards the port helm of the yellow boat, with IT and electronics technicians playing with the setup. Foil arm tests were conducted on the yellow boat, with both arms lifted at varying angles. Both boats subsequently docked out at 1200hrs, both with one design sails, while the yellow boat had the new foil (04124002-FW6) on starboard.
The 'Garbi' afternoon thermal wind varied throughout the day, starting with 3-5 knots from 150 degrees, increasing to 9-12 knots, and then subsiding to 7-9 knots and 5-8 knots by the end of the sailing day.
Wave height fluctuated between 0.3m-0.5m, with a period of 3secs. The sailing day was broken up into six stints.
Stint 1 started at 1320hrs with a tow start, however, the Barceloneta sailing area did not provide sufficient wind to maintain flight. The yachts were towed towards the airport sailing area further south, in search of more wind. A side-by-side port reach comparison of the new starboard foil on the yellow boat with the one design foil on the red boat was the highlight.
Stint 2 saw the yachts towed back up north, allowing them to compare higher sailing angles while sailing side by side on a port tack down the coast. The day's third stint included upwind split tacks, ending in a close call as both boats converged. This stint was interrupted when the yellow boat spun out during a tack to starboard.
Stint 4 consisted of the yellow boat sailing a short upwind and downwind course around the red boat, which appeared to be dealing with a stuck jib halyard, prompting a crew member up the rig to release it. Both J1 jibs were replaced with One Design J2 jibs.
Stint 5 involved 10 synchronised tacks upwind, followed by a long downwind leg towards Barcelona, and nine gybes. Followed by another long upwind tack on port. The yellow boat demonstrated impressive sailing by gaining significant height at similar speeds to the red boat while the wind was stable. After, the red boat continued practicing while the yellow boat took a short break.
The final stint, Stint 6, was a downwind gybing duel in lighter winds. It ended with the yellow boat losing flight on its new foil and being tow-started, while the red boat sailed a long reach before a significant touchdown gybe. After this, the yellow AC40 was towed back to base while the red boat continued another short stint before returning.
After the sailing session, sailing, sail trimmer Lucien Cujean mentioned that the day was productive, with a lot of important metrics gathered during the side-by-side sailing of the two boats.
The boats returned to base at 1735hrs, with crane-out operations complete by 18hrs30. In spite of challenging conditions and a focus on testing their new foil, the team performed 50 maneuvers, with 88% fully foiling.
They spent almost six hours on the water and covered a record 96 nautical miles. The day's activity was so extensive that the recon rib returned with just 1 bar of fuel left on the gauge, having started the day with a full tank.
Session Statistics: Alinghi Red Bull Racing LEQ12 - Day 43 - July 19, 2023 - Barcelona
- Weather: Sunny 39 degreesC
- Wind Strength 7-12kts
- Wind Direction: 150 degrees-180 degrees
- Sea State: Flat
- Crane In: 0940hrs Dock Out: 1200hrs
- Dock In: 1735hrs Crane out: 1755hrs
- Total Tacks: 26 - Fully foiling: 25; Touch & Go: 1; Touch Down: 0
- Total Gybes: 24 - Fully foiling: 19; Touch & Go: 4; Touch Down: 1
Crew: Arnaud Psarofaghis, Maxime Bachelin. Nico Charbonnier, Pietro Sibello, Bryan Mettraux, Yves Detfry, Lucien Crujean, Yves Detry, Nico Rolaz
Additional Images:
This commentary was written and compiled from video, still images and statistical content extracted from the AC37 Joint Recon program and other material available to Sail-World NZ including photo files, and other on the water coverage from the 2010, 2013, 2017 and 2021 America's Cups. Its format is intended to give Sail-World readers a snapshot of all teams' progress on a given day or period.