Nacra 15 Qualifiers BA 2018. Live Tracking at sailracer.org/eventsites/live-screen-tracking.asp?eventid=210949

Aug 13, 2013

AC34, Timed Loss on Tacks & Gybes



All Images Guilain Grenier: Oracle training at the bay this week.
Artemis showed incredible speed in straight line considering the little time sailing with Big Blue. Artemis even won two starts leading to the first mark but simply lost the lead to Luna Rossa  perfect foiling gybes.
AR upwind performance was even better, but couldn´t compensate for their huge loss on the downwind legs. In the end that raw speed was not enough.

Handling and smooth transitions in cats are way more critical than their monohull counterparts on the speed loss, as you can blow off your dinghy or monohull gybes but the shape of these boats and the inertia involved will keep them somehow flowing. With cats you can simply have a dead stop, and while tacking you can even go backwards.

The same expert that has provided us the only available serious polars diagrams published last week has also analyzed the time lost on each maneuver, and to my surprise and beyond what I wrote above he related to the V5 monohull data.

The point is that speed has always been key to win the Cup, but this foiling edition is showing how important is to nail your manouvers. From all the footage and races we've seen New Zealand has achieved the most impressive handling so far. First races against Luna Rossa were just a joke, remember they even won one by 7mins.

Of course Luna Rossa has improved a lot, and they seem quite fast, confident and focused in last two matches, they will have the advantage of these additional 4 races, but it is clear TNZ also has been training and improving their almost perfect handling.

Oracle is having an intense two boat race testing program, pushing the boats hard and flying fast. But we still didn´t saw a good quantity of footage on consistent consecutive and smooth foiling gybes, although they might have them mastered by now, we'll need to wait to see how they handle the pressure in real racing.

The Louis Vuitton Finals are coming next week, seeing how close Luna Rossa will be now against the Kiwis will give also an idea on how close Artemis was to reach optimal range.
In the Cup finals Oracle will possibly be faster .....but how much faster can they be than TNZ? After seeing the almost same speed in several legs between LR & AR, two pretty different concepts, I was amazed on how similar speed they had.
So I'm pretty sure that TNZ/LR & Oracle will show quite similar speeds at the end,  and the last minute additional factor could be foiling upwind.

Based on this even speed considerations the most important aspect left will be handling & maneuvers, the team doing the best ones will win this Cup.

Throwing spray looks specatular but all teams should avoid them as the level of handling finesse may reach a point where those little seconds lost in dragging the bow may force you to lose a race and maybe the Cup itself.
Below data report and analisys by CSN special expert anon contributor.
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Tack & Gybe Loss
TNZ data files were analyzed, some losses are obviously exaggerated due to the boundaries dictating tacking off a lift, or into a lull.  wind data or current weren not taken into account:

- Good gybes are 30mts VMG loss; the worst are 150mts.
- Minimum speeds during gybe average 24knots
- 2-10second loss

- Average tack loss is 38mts, but a few tacks in the last race were 32mts.
- Worst tacks are 100mts loss.

- Bottom speed is 10konts
- 4 sec loss

In similar windspeeds the v5 yachts lost about the same amount of time.
- Tack loss 15-20m – 4 sec loss
- Gybe loss 15 – 50+m 3-10sec loss (big variability in Gennaker gybing)

Estimates for Race 3 of Semis:

Team
Av Distance Lost, Mts Bottom Speed Min, Knots
Luna Rossa Tack 34 9

Gybe 26 26
Artemis Tack 47 7

Gybe 34 23

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