Cup Spy April 24: Swiss stretch out in their radical AC75. American Magic reach a key milesone
by Richard Gladwell/Sail-World NZ 24 Apr 16:56 NZST
24 April 2024
Tail-plane appears prominent and should tidy airflow as it leaves the hull - Alinghi Red Bull Racing- AC75 - Day 6 - April 24, 2024 - Barcelona © Ugo Fonolla / America's Cup
Two teams sailed today - both in Barcelona, which turned on a southerly breeze that was rock-steady at 180°, but varied in pressure - starting the day at 5kts and finished at over 15kts. At the America's Cup wave buoy off Barcelona, it recorded an easterly cross sea of just under a metre at 90° to the wind direction of 180°.
What happened in the Cup - April 24, 2024:
- INEOS Britannia - continued with set up on their new AC75 in Barcelona. This was their fourth day in this process. No report was filed today by the AC37 Joint Recon team, and presumably, the AC75 did not leave the boat shed.
- Alinghi Red Bull Racing - had a good session in a variable pressure breeze that started light at 5kts and built to 16kts at the end of the session. The Swiss weren't too good on the corners - upwind - only achieving two dry tacks out of 12 attempts. However the sea state that was at 90° to the wind didn't help the Swiss AC75 now on its fourth day of sailing. We saw some interesting aspects of the Swiss design - in the wing foils and aerodynamics - particularly around the foredeck but the AC75 generally. We've got plenty of images in this report, and a key image which very simply explains how the foil arm and wing foil rules work. As a total package this boat looks like it should be quick, but may be challenging for the crew to sail - to get the best out of it. They had a minor mainsheet issue bringing a slightly early end to the session.
- Emirates Team New Zealand - had a day in the shed. They have been out today April 25 ANZAC Day (a war memorial/remembrance day in AUS and NZL). They are expected to keep sailing until early May, resuming in Barcelona in early July.
- American Magic - sailed paired AC40s for the final time in keenly contested match racing with more sail testing setting two mainssials and six jibs between the two AC40s - with another three carried on their Chase boat. Their AC75 is one of two AC75s yet to be revealed. It arrived at the base on March 26 and will be launched in early-mid-May.
- Orient Express Racing Team - Their AC75 is the other yet to be revealed. It is to an Emirates Team NZ design. They were sailing in the AC-40 One Design tody.
- Luna Rossa Prada Pirelli - No report was filed today by the AC37 Joint Recon team, and presumably, the AC75 did not leave the boat shed.
Commentary: Focus on Foils
America's Cup tragics will have a field day analysing the various aspects of Alinghi Red Bull Racing's radical design. However the real test is how the elements all work together on the water. It is too early to make any calls as to how the total package works, and who has got it right, let alone get into the Black Art/Science of wing foil design.
From the 2021 America's Cup, we know that the primary objective of the wing foil design is to get the AC75 self-launched onto its foils in the lowest possible wing speed. A secondary objective is to have foils that are as fast as possible once the AC75 is foiling. The third objective is to make the boat as easily controlled as possible by the crew - while still achieving the first two objectives.
The rules governing Wing Foils have changed from the 2021 America's Cup to the 2024 event. Simply, the changes are a reduction in total weight, by 230kg total (115kg per side), and a increase in wing foil span from 4 metres to 4.5metres (250mm per side).
The Swiss are the first to show a set of wing foils which comply with Version 2 of the AC75 Class Rule which applies for the 2024 America's Cup.
Here's a quick outline as to how the rules work in the arcane field of foil wing design - there are plenty of options for design teams to explore. They are allowed just four wingfoils on a new AC75 - maybe two test foils (each different) and then the final race set, or have two race sets. Unlike the 2017 America's Cup, the teams are not allowed to fit a different set of foils each race day. They must make a decision as to which wing foils they wish to race with for each round - and are committed to that pair of wing foils for the duration of that round, and change between rounds, if they wish.
In the image there are two parts - the Foil Arm (dark blue), starting just above the upper white line, and the Wing Foil (black), which starts just below the upper white line.
Like the 2021 America's Cup the Foil Arm is a supplied one design part and are identical to those supplied for the last Cup.
The teams design the wing foil within various parameters which are controlled to maximum dimensions in the rule. These have changed since the 2021 Cup.
The weight of each Wing Foil and its Foil Arm has effectively decreased by 115kg, however there is a Centre of Gravity measure point to be met.
The allowed depth of the Wing Foil (attached to the Foil Arm) has increased by 250mm from 700mm to 950mm between Version 1 and Version 2.
The Foil Arm and Wing Foil weight reduction (by a combined total of 230kg) is part of the lightening of the AC75 by almost a tonne.
While the weight of the Wing Foil and its Arm has decreased, which will assist light wind foiling so will the increased wing span dimensions which have increased by half a metre in total (250mm per side). This has another light and strong wind foiling benefit, as it is now easier to distribute the reduced weight in the foil and bulb - achieving a drag reduction and improved foil performance.
Luna Rossa Prada Pirelli and Emirates Team New Zealand are still sailing with so-called Legacy Foils - or a set which are from their 2021 campaign. The Kiwis say they will fit Version 2 Wing Foils to the Foil Arms when they arrive in Barcelona - allowing more design and build time.
AC37 Joint Recon Team Reports:
Alinghi Red Bull Racing - AC75 - Day 109 - January 10, 2024 - Barcelona
Alinghi Red Bull Racing's second sailing day of the week saw the Swiss team make the most of a Barcelona Spring day that delivered un-sailable light winds until after mid-day but then developed into a solid sea breeze that built to peaks of 16kts by the late afternoon.
The session took place on a sea state that began flat but morphed into a moderate chop with some slightly offset swell of around 0.5 metres. The Swiss AC75 was rolled out at 0933hrs to be rigged and launched by 1002hrs, followed by two and a half hours of testing and setup on the dock before the boat set out at 1230hrs.
Once in the harbour basin the M1-1 mainsail and J2-1 headsail were hoisted by 1250hrs before the boat left the harbour on a bow tow at 1302hrs. The tow was almost immediately dropped and the crew began their first flight just three minutes later in around 7-8kts of breeze (with we believe a celebrity guest in one of the cyclor positions).
This flight lasted 10 minutes before it ended in a touchdown tack. The second flight lasted a similar time and saw a bear away and foiling gybe before ending in a touchdown turnup followed by a displacement tack. The next flight (around 20 minutes) was mostly upwind and saw seven touchdown tacks in 7-9kts of breeze.
A 10 minute break was followed by another 20 minute flight (mostly downwind) with three touchdown gybes and two foiling gybes. A 10 minute break was followed by another flight (10 minutes) with the breeze now up to 11-12kts that featured four foiling gybes, one foiling tack, and one touch and go tack, before a stop at 1525hrs to change down to the J3-1 headsail as the southerly wind ramped up to 13-15kts. The following 15-minute flight saw the crew practising high speed one-board bear aways and round ups and included a touchdown tack and four foiling gybes.
This run came to an end at 1406hrs off Badalona, when – after a short break – sails were dropped and the boat was put on a foiling bow tow back to the harbour. The recon interview revealed that there was a reportedly minor issue with the mainsheet system. The boat entered the harbour on foils at 1647hrs and was back on the dock at 1705hrs. No sailing is scheduled for tomorrow Thursday April 25.
Report by Justin Chisholm
Crew: Sailing: Arnaud Psarofaghis, Maxime Bachelin, Nico Charbonnier, Nico Rolaz, Bryan Mettraux.
Power: Théry Schir, Florian Trub, Neils Theuninck, Augustin Masillefer
Session Statistics: Alinghi Red Bull Racing - AC75 - Day 6 - April 24, 2024 - Barcelona
- Weather: 13° - 15°. Scattered cloud.
- Wind Strength 5-16kts
- Wind Direction: 180°
- Sea State: Moderate chop slightly offset swell 0.5metres
- Crane In: 1000hrs Dock Out: 1230hrs
- Dock In: 1700hrs Crane out: 1800hrs
- Total Tacks: 12 - Fully foiling: 2; Touch & Go: 1; Touch Down: 9
- Total Gybes: 16 - Fully foiling: 11; Touch & Go: 0; Touch Down: 5
American Magic - AC40/LEQ12 x 2 - Day 115 - April 24, 2024 - Barcelona
NYYC American Magic: AC40-8 ‘Magic’ was craned in at 10:15hrs and AC40-5 'America' was craned in at 10:35hrs. The recon team observed a team of three at the dock performing load tests in a bench test, for what we thought could be the shrouds for the new boat. Dock out was at 12:30hrs and ten minutes later they hoisted mainsails: MC-4 for ‘America’ and MC-2 for ‘Magic’, paired with J1.5 custom jibs.
There was no wind blowing after hoisting the sails, so the team waited at the entrance of the harbour until 13:15hrs when a gust of 5-6kts from 180º came in and America started sailing upwind but stopped soon after performing two tacks. The wind dropped and the team kept waiting until 14:00hrs when again a breeze of 5-7kts from 180° came and after some time became more solid. From here the sailing session progressed as follows:
Phase 1 (50minutes): Wind: 5-7kts from 180º. America sailed upwind for four really long tacks, while Magic still was at the entrance of the harbour stopped. America suddenly bore-away while sailing upwind on port tack, to start sailing downwind. After two gybes, they managed to meet Magic who had started sailing. Both AC40s sailed downwind in speed-test mode until they found the starting line, that was set by one of the chase boats in front Port Olímpic. Magic stopped for some checks and America kept sailing performing many manoeuvres around the pre-start box. Due to the size and direction of the swell, manoeuvring with the AC40s was complicated as it was quite easy for the foils to break the surface.
Phase 2 (20 minutes): 6-8kts from 180º. Two pre-start completed in this phase. In both, America was into the box before than Magic. In the first start America crossed the line leeward of Magic, both in the middle of the starting line. Magic was too close to America and finally got into the wind shadow, losing speed. After sailing for two tacks, they both came back to the starting line. In the second start, it was Magic who crossed the line to leeward of America but 2-3 seconds before the start her hull touched the water and lost some speed, not much, but enough for America to get over Magic and assume a dominant position. After two tacks they came back to the start line and stopped to change the J1.5 jibs for J2s.
Phase 3 (40 mins): 10-14kts from 190º. A complete race with two upwind/downwind laps was completed in this phase. America got in first into the pre-start box and immediately wanted to gybe from port to starboard where she almost capsized. She managed to get onto the foils just in time and started on port tack while Magic started on starboard. An intense battle on every leg ensued but the highlight was the rounding at the top mark of the second lap. Magic tacked just in front and very close to America and then America tried to attack from leeward when bearing away into the downwind and then after America attacked from windward to Magic, finally managing to beat her in the downwind. America won the race by a few meters. When finished, they stopped to replace batteries and change jibs J2 by jibs J3.
Phase 4 (50 minutes): 14-16 kts from 190º. Two pre-start were completed in this phase. In both, Magic was into the box before America in the pre-start. In the first start America started at the pin and Magic in the middle of the line. After two tacks they came back to the starting line. In the second pre-start they made the ‘waiting’ strategy that we’ve seen before with both boats waiting off the foils until the last 40 seconds and then lifting off on the foils and having a close battle until the starting line. America started close to the pin and Magic in the middle of the line. They continued into an upwind/downwind race that was won by America again by a very short gap.
This was the last sailing session with the AC40s for the senior American Magic Team, as after this race the team sailed to Badalona harbour where the AC40s will have their new base for the Youth and Women’s America’s Cup teams.
Dock in was completed at 17:20hrs.
Jose Piñana AC Recon
Crew: Co-Helms: America: Paul Goodison, Tom Slingsby, Magic: Lucas Calabrese, Riley Gibbs..
Trimmers America: Andrew Campbell, Michael Menninger; Magic: Severin Gramm, Kyle Langford.
Session Statistics: American Magic - AC40/LEQ12 x 2 - Day 115 - April 24, 2024 - Barcelona
- Weather: 16°C - Sunny.
- Wind Strength: 4kts-14kts
- Wind Direction: 180°-190°
- Sea State: 0.9 - 1.14mtrs 098°
- Dock Out: 1230hrs
- Dock In: 1720hrs
- Total Tacks: 35/28 America/Magic - 85% dry foiling
- Total Gybes: 35/28 America/Magic - 85% dry foiling
Additional Images: