zezo polars vs VR polars
Post by iconPost by lucarc | 2020-11-29 | 13:31:54


It seems that the polars from the game (thanks again toxxct for your polars) do not fit the polars form zezo when it comes to a TWA around 135° and a wind speed around 26Knts / 28Knts, making us use the C0 sail instead of the HG in the game, while zezo thinks it is otherwise.

I know this issue of little differences between zezo and the game is already known, I just wanted to notice you about this fact. For those sailing in the 40°S, you may lose close to a mile with 2 changes of sail really quickly if you do not pay attention.

commenticon 4 Comments
Post by iconPost by zezo | 2020-11-29 | 14:22:42
The indicated sail is not exact. It's defined statically within +/- 0.5 knots

The sails are equal at 135° between 26 and 27 knots. And above 27 the router should not select 135 because there is a dip in the polars.

Post by iconPost by lucarc | 2020-11-29 | 15:28:21
Okay, I got your point. I thought this was due to the polars from this link, which indicates HG to be the best sail at TWA 135 for winds slower than 27 Kts : http://zezo.org/vg/polars.html?opt=0

At TWA 135°, the transition between C0 and HG is set at 26,9 Kts with these polars, whereas it is 26,4 Kts in the game.

Thanks for answering though
Post by iconPost by zezo | 2020-11-29 | 15:47:21
26.9978 actually. That's 50 km/h. Leftover from the time the game polars were defined in km/h years ago. Best sail is still defined in terms of km/h

The router actually uses a 'composite sail' which is a single polar with indication of the best sail at certain speeds. But it only contains finite number of points (130)
Post by iconPost by toxcct | 2020-11-29 | 19:25:29
On my App though, each sail can be seen altogether on the same chart
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