Geneva · Saturday 19 September 2026

• Be on the line at the gun: our R3 and R5 starts cost the most today. In R5 we crossed 20 s after the gun, 45 m back at 7.6 km/h when it went. We were 6th at mark 1, 74 m behind the median boat. In R3 we bore away early and were 28.5 m back at the gun, then 5th at mark 1 and 65 m behind the median. The winners of those starts (AUS in R5, SUI in R3) were 11-18 m from the line, with 3.6-3.8 s of time on distance against our 21.3 and 5.8 s. R1 shows it works: 8 m from the line, the hardest acceleration in the race (0.72 km/h per s) and joint 2nd at mark 1.
• Carry speed into the first leeward gate: we were slowest through it in every race. Exits were 6.8, 7.3 and 4.2 km/h (R1, R3, R5) against the other five boats' median of 10.4, 12.1 and 7.2. Entries were already 1.7-6.8 km/h below theirs, so the loss is the final approach, not the turn. In R1 we gybed 13 s before the gate and dropped to 6.5 km/h. The last gate roundings onto the finish leg, in 11-14 km/h, were the opposite: fastest out in R1 and R5.
• Downwind, sail deeper. In displacement a deeper angle went with more VMG on 32 of 36 boat-bands across the fleet, and our own fastest quarter of periods ran at 128 deg against 116-119 deg for the slowest. In R3 and R5 the best boat on the runs sailed about 6 deg deeper than us (SUI 129 against our 123.5; GBR 128 against 122). Our speed at the same angle was fine (+0.3 km/h over 140 periods at 10-12.5), so the gain is in the angle. SPEED v2 asks for 133 deg at 7.5 km/h and 127 at 10; we sat at 122-123.
• R5's first run: check the board cant. Both boards sat at 0.5-2.5 deg, about 2-3 deg more cant than we used all day (median 4.2) and than the fleet (4.2-4.9). In 7.5-10 km/h those 26 periods were 0.8 km/h slower than all boats at the same angle, against 1.0 km/h faster for our other 55 periods in the same breeze. We then reached the gate at 3.7 km/h. Ask the flight controller whether it was deliberate.
• Upwind, a harder jib sheet and more cunningham. In displacement a harder sheet went with more VMG on 38 of 38 boat-bands, and more cunningham on 26 of 38 (7 the other way). The upwind leg winners ran the jib harder: GBR in R1 at 38 % eased with 483 kgf of cunningham (us 42 %, 127 kgf), AUS in R3 at 35 % and 143 kgf (us 43 %, 82 kgf). In R5 we tied for best at 46 % and 71 kgf. The jib study for Liv found the same: about half the fleet's cunningham.

• 15:34:59 (13:34:59 UTC) R1 start: our best one. 8 m from the line at the gun, then the hardest acceleration in the race.
• 15:38:00 (13:38:00 UTC) R1: gybe 13 s before the leeward gate, 6.5 km/h at its slowest. We then rounded at 7.4 km/h in and 6.8 out, slowest of the six.
• 16:05:59 (14:05:59 UTC) R3 start: already reaching 15 s before the gun and 28.5 m back when it went. Compare SUI, 18 m back at 17.0 km/h, which led at mark 1 by 25 s.
• 16:09:54 (14:09:54 UTC) R3 first leeward gate: 9.2 km/h in, 7.3 out; the other boats' median was 16.0 in and 12.1 out.
• 16:46:59 (14:46:59 UTC) R5 start: 45 m back at the gun; we crossed at 16:47:19. AUS crossed 2 s after the gun and led at mark 1.
• 16:49:05-16:52:44 (14:49:05-14:52:44 UTC) R5 first run: both boards at 0.5-2.5 deg of cant, angle swinging 98-141 deg.
• 16:53:20 (14:53:20 UTC) R5 first leeward gate at 3.7 km/h in and 4.2 out, against 7.3 and 7.2 for the others.
• 16:58:29 (14:58:29 UTC) R5 last gate rounding onto the finish leg: fastest of the six (18.8 km/h in, 16.4 out).

Upwind was mid-pack, and no single setting held us back. VMG ranks: 6th of 13 at 7.5-10 km/h (44 of our periods; best SWE, 81), 5th at 10-12.5 (110; best SWE, 28) and 3rd at 12.5-15 (20; best USA, 29). Race by race against the five boats in our races (wind-fair ranks): 5th, 2nd and 3rd.

• Angle. Sailing high was fast for everyone in displacement: the fleet's fastest quarter of periods sat at 48 deg TWA against 68 deg for the slowest, and all 38 boat-bands agreed. We already sail high: 47.5 deg at 7.5-10 against the fleet's 55.8 (SPEED v2: 49.7), and level with the fleet above 10 km/h.
• Jib. See the headline on sheet and cunningham. Our lead is already on the fast side, inboard of the fleet at 56-58 % against 61-65 % (0 % = fully inboard). An inboard lead went with more VMG on 32 of 38 boat-bands.
• Cant. The table flags ours as the lowest number in the fleet, which means the most cant: 2.6 deg against 4.7 at 7.5-10, and 4.2 against 4.8 at 10-12.5. Upwind in displacement, cant showed no link with VMG (15 boat-bands one way, 14 the other), so it is not a priority.
• Practice vs racing. We raced much higher and faster than we sailed in the warm-up: at 10-12.5, 50 deg and 9.7 km/h of VMG racing against 63 deg and 6.2 in practice. The fleet did the same (+3.1 km/h of VMG), so the warm-up upwind was simply not sailed hard. It is not a racing problem.

VMG ranks: 8th of 13 at 7.5-10 km/h (81 of our periods; best SWE, 80) and 8th at 10-12.5 (140; best USA, 55). In our races we did better: 3rd, 3rd and 4th of 6 (wind-fair). At 12.5-15 we are 12th of 13, but the best boat there (SWE, 6 periods) was foiling 67 % of the time; on displacement periods only we are 11th of 12. Read that band as thin.

• Angle. See the headline and the deep dive. We sail 2.5-3 deg higher than the fleet median (122.4 against 125.1 at 7.5-10; 122.7 against 125.7 at 10-12.5), and deeper paid on almost every boat.
• Wing. Ours is the least rotated wing in the fleet downwind (31.5 deg against 38.3 at 7.5-10; 33.0 against 38.0 at 10-12.5), with the clew nearer the centreline (623 mm against 900-960). The fleet data does not say this is slow: less rotation went with more VMG on 23 of 36 boat-bands. No change suggested.
• Jib. We keep it trimmed on the runs (58-62 % eased) while most boats let it fully out (81-100 %). We were 3rd in R1 and R3 with it, and across the fleet sheet position shows no link with VMG (12 boat-bands one way, 13 the other). Keep it.
• Leeway. We slip 1.7-1.9 deg against the fleet's 1.4. That fits sailing higher.
• Practice vs racing. At 7.5-10, our racing periods (29, mostly R5) were 1.5 km/h of VMG below our own warm-up in the same band, while the fleet held level (-0.2). That is R5's first run; see the board cant headline.

Leg 1 only, start to mark 1, taken as 2 s chunks of the steady part. No band had enough boats to compare, so these are race by race and thin (3 chunks each): R1 1st of 6 on VMC (25.8 km/h against the fleet's 21.6) and R3 2nd (17.7 against 9.9). R5 had too little steady reaching to compare. The reach was not where we lost; the starts before it were.

Light air made every tack and gybe a displacement turn, so the touchdown counts mean nothing today: nobody was foiling. Ranked on VMG through the manoeuvre:

• Tacks. Only 10-12.5 km/h had enough boats: 8th of 8. Our 3 tacks there include two in practice, one of which (15:45:37, 13:45:37 UTC) lost 98 m. Our racing tacks were good: 15:39:40 (13:39:40 UTC, 10.7 km/h through), 16:12:03 (14:12:03 UTC, 9.9) and 16:55:34 (14:55:34 UTC, 8.6). FRA's best of the day was 10.5. That is too few to rank.
• Gybes at 10-12.5 km/h. 4th of 7 (8 of our gybes): 9.0 km/h through against the fleet's 9.1. We exit at 10.1 km/h against 11.3. The best boat (ESP, 2 gybes) was still partly foiling in R2, so it is not a like-for-like target.
• Gybes at 7.5-10 km/h. 7th of 8 (3 of our gybes): in at 10.0 km/h against 11.7, out at 8.3 against 9.4.
• Worst racing gybe: 15:38:00 (13:38:00 UTC) in R1, 6.2 km/h through, 13 s before the leeward gate. See Mark roundings.

See the headline: R3 and R5 were the day's biggest losses, and in light air they came from being late to the line, not from the pivot.

The R3 and R5 winners at mark 1 (SUI, AUS) were 11-18 m from the line at the gun, with 3.6-3.8 s of time on distance. CAN won mark 1 in R1 differently, running in from 43 m back at 13.6 km/h.

The pivot in light air came after the gun. In R1 five of six boats were still at 12-38 deg TWA 3 s after it, so their pivot start reads +2.9 s, the end of the search window. Over that pivot our acceleration was the best in R1: 0.72 km/h per s against 0.62 for ITA, 0.53 for AUS and 0.45 for GBR. Reaching 90 % of reach speed took 25 s, not the 5-7 s of a foiling start. In R3 we were already reaching 15 s before the gun, so there was no pivot. In R5 we never got to 90 % before mark 1.

Leeward gate (5 km/h bands): 13th of 13 on exit speed at 5-10 km/h (2 of our roundings; fleet 7.9 km/h out, us 5.3) and 10th at 10-15 (4 roundings; fleet 21.0, us 11.9). The fleet figure at 10-15 includes boats foiling in R2. The fair comparison is within our own races; see the headline and the deep dive. At the first gate of each race we were last or second last in and out, while at the last roundings onto the finish leg (R1 and R5) we were fastest out.

Mark 1: 4th of 10 on exit speed at 10-15 km/h (2 roundings; 23.8 against the fleet's 20.6). Windward gate: 6th of 9 at 10-15 (3 roundings; 21.5 against 24.3).

In displacement, VMG downwind comes from the angle more than the speed. Over all kept displacement periods at 7.5-12.5 km/h (2,645 periods, 13 boats), deeper went with more VMG on 32 of 36 boat-bands. The fleet's fastest quarter sat at 135 deg, the slowest at 117.

Our speed at the same angle was not the problem: at 10-12.5 our racing periods were 0.5-2.4 km/h faster than all boats at the same TWA, depending on the race. The second chart puts each boat's runs in each of our races on one point, angle across and VMG against the race's median boat down. In every race the two highest boats (AUS and ITA, 115-122 deg) were the slowest, and the best boat on the runs sailed at 128-129 deg. We were at 127 in R1 (2nd on the runs) but 123.5 and 122 in R3 and R5.

Try: on the runs in under 13 km/h, sail 4-6 deg deeper (about 128 deg) and hold the speed. The SPEED v2 targets (133 at 7.5, 127 at 10) point the same way.

From 16:49:05 to 16:52:44 (14:49:05-14:52:44 UTC) both boards read 0.5-2.5 deg of cant. The rest of the day we sailed downwind at 3.9-5.6 deg (10th to 90th percentile), and under 3 deg on only 1 % of our periods. Of 977 other boats' periods in the same 7.5-10 km/h band, only 50 were under 3 deg, 39 of them DEN's.

In that band our 26 race 5 periods were 0.8 km/h slower than all boats at the same angle, while our other 55 (52 of them in the warm-up) were 1.0 km/h faster. That is 1.8 km/h in the same breeze. The run ended with a 3.7 km/h entry to the leeward gate, the slowest of the day.

This is one run, and the breeze was patchy (8.4-11.9 km/h, with the angle swinging 98-141 deg), so treat it as a question, not a finding. Was the extra cant chosen, and if so, what was it for? If the data reads it right, it is the clearest single difference between our slowest downwind and the rest of the day.

Our leeward gate roundings in under 13 km/h, against the other five boats in the same race at the same gate (one rounding each):

Speeds in km/h. We lose little in the turn itself (0-1.7 km/h, like the others); the deficit is already there on the way in. In R1 it was a gybe 13 s before the mark, and in R5 the slow first run. Our two last roundings onto the finish leg, in 11-14 km/h, were the fastest out of the six (18.9 and 16.4 km/h). Worth a look on video at how the others set up the final approach: they arrived at 7-16 km/h.

Medians over each boat's upwind periods in the race (21-50 periods each):

Across the fleet's displacement sailing, a harder sheet went with more VMG on every boat in every band (38 of 38), and more cunningham on 26 of 38. Part of that is pressure: a puff loads the jib and lets the trimmer sheet harder. But the leg winners ran harder sheets than us in the same breeze, and the jib study for Liv found our cunningham at about half the fleet's in foiling conditions too. Try: upwind in displacement, about 38 % eased and at least 140 kgf of cunningham, then see if the VMG follows.

• Wind bands: 2.5 km/h, on each boat's own wind reading corrected by its calibration offset for the day. Offsets (km/h, + = the sensor reads high), from moments boats sailed within 150 m of each other: AUS -0.3, BRA -0.8, CAN +0.6, DEN -0.3, ESP +1.0, FRA -0.9, GBR +0.0, GER +0.1, ITA +0.0, NZL -0.3, SUI -0.2, SWE +0.2, USA +0.8.
• Bands are never merged. A band is shown only with at least 5 of our periods and 3 other boats with 5 each; for manoeuvres and roundings, 2 of ours and 3 other boats with 2 each.
• Racing is split by leg (leg 1 = reaching, the final leg left out). Practice is split by wind angle: upwind at or below 75°, downwind at or above 110°.
• Samples: 6 s straight-line periods from the app (upwind, downwind), each the mean of its ~12 half-second readings; 2 s chunks of the steady part of leg 1 (reaching: 10 s after the start to 5 s before mark 1).
• Period filters: a period is left out if it starts within 10 s of one of the boat's tacks, gybes, bear-aways or mark roundings (the boat is still accelerating), or if it is under 80 % of the boat's own VMG target (bad air, not trying). The floor also takes out genuinely slow sailing, so the table below shows what it removed race by race.
• Light day. Periods need at least 8 km/h of boat speed and tacks and gybes at least 8 km/h at the crossing, because the boats sailed and turned in displacement. The VMG floor applies to foiling periods only (both hulls at least 500 mm clear): the targets assume foiling, and against them most displacement sailing sits under 80 %. Foiling and displacement periods are compared separately where it matters.
• Every comparison is a median over that boat's samples, never a single sample. Fleet = the median of the other boats' medians, so each boat counts once. Best boat = the other boat with the best median: VMG (km/h) upwind and downwind, VMC to mark 1 on the reach, VMG through the manoeuvre on tacks and gybes, metres below target on bear-aways, exit speed on roundings, metres at mark 1 on starts. VMG % is against each team's own polar, so it is shown for us but never used to rank boats.
• Targets: SPEED v2 cheatsheet, LAB2 27m with the Big jib and LARW rudders: the sheet's row at the band's lower wind speed (the 30 km/h row for 30-32.5), as written, never interpolated. Clew targets are converted to mm with the sign turned round (- = to windward, as in the data); jib track is converted from sheet angle to jib lead % (0 % = fully inboard). Not compared: jib sheet load (the sheet's units are not kgf yet).
• Phases included: practice, racing. Races left out: none. Crew on board: 4. Notes: none.
• Manoeuvres are free manoeuvres only: anything within 10 s of the start, a mark or the finish belongs to the Mark roundings tab, and anything after the finish is left out. Practice tacks and gybes with an app quality score under 25 are left out (the boat was not trying); racing ones are all kept.
• VMG through the manoeuvre = ground made upwind (tacks) or downwind (gybes) over the app's 25 s window, in km/h - the measure that compares boats directly. Metres lost is the app's ghost-boat figure; each ghost holds that boat's OWN pre-manoeuvre VMG, so a boat that was quicker going in shows more loss for the same turn. For bear-aways it is distance sailed below the boat's target speed over 15 s. Touchdown = lowest hull under 100 mm.

What the filters removed