A note on this race's data

The boat's through-water speed sensor recorded 0.0 kn all race, and the wind numbers on this page are apparent wind, not true wind (true wind can't be calculated without boat speed). Everything below is therefore reconstructed: boat speed comes from the Vakaros unit's GPS speed over ground, and true wind is recalculated from the recorded apparent wind and that GPS speed. Speed over ground can include a small current effect that through-water speed wouldn't, and any error in it carries into the true wind and angle figures, so treat the numbers as good estimates rather than exact readings. The comparable race below used a working paddle wheel, so the comparison isn't perfectly like-for-like. Tacks vs. gybes are inferred from the reconstructed wind angle at each Vakaros-detected turn.

Wind & Comparable Races

Reconstructed true wind ranged 2.0–10.5 kn (avg 5.6 kn) — light, and per the race note patchy ("the basin was a maze of different winds"). The closest comparable is race 8 (2025-09-24, Wed Nights), a 2-up race in similar light air (0.6–14.0 kn, avg 6.5 kn during the measured legs).

Against the J/80 polar, the boat reached 61.5% of target upwind, 61.3% on the reach, and 81.3% downwind — ahead of race 8 on every point of sail (58.8%, 46.0%, 67.4%), with the run the clear high point. On angles, upwind TWA averaged 48.4° against a 42.6° target, 5.7° wide (footing low), while downwind it averaged 135.5° against a 145.8° target, 10.4° tight (higher than target depth). Race 8 showed a similar downwind pattern (9.2° tight) but was much closer to target upwind (1.1° wide), so the wider upwind angle is the difference worth watching: at 61.5% of target speed, footing low isn't yet paying back in speed.

Fourteen tacks were logged — a lot for a 1:44 race, consistent with a shifty night — averaging 7.1s and 35.2% speed loss, against race 8's 4 tacks at 31.8% loss and 11.5s. One gybe was logged and it was expensive (54% loss, 16s), against race 8's 3 gybes averaging 18.2% loss; a single gybe is too small a sample to read much into. Two further turns landed in the reach zone where tack vs. gybe can't be told apart, and four mark roundings were detected from the GPS track. Heel stayed low (8.5° upwind, 5.0° downwind) in the light air.

Coaching Recommendations

1. Upwind the boat sailed about 5.7° wider than the target angle but only reached 61.5% of target speed — in light air like this, the extra footing isn't buying enough speed to justify the lost height. Worth testing a slightly higher, more patient groove upwind on nights like this.
2. Downwind was the strongest leg (81.3% of target), even sailing about 10° higher than the target depth — the same tight-angle habit seen in race 8. It's working for speed here, but it's worth checking whether a deeper angle in the puffs gains more VMG.
3. Fourteen tacks at 35.2% average loss is a heavy tacking load for a light-air night; each one bleeds more speed than race 8's tacks did. Keeping tacks to genuine shifts, and rolling them through more smoothly, is the most direct place to recover time. The single gybe (54% loss) is a one-off to keep an eye on, not yet a pattern.