From: Pierre St. Hilaire (
Date: Tue Aug 25 1998 - 10:52:49 PDT

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Date: Tue, 25 Aug 1998 10:52:49 -0700
From: "Pierre St. Hilaire" <>
Subject: Re:  COTW
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>Ignore the 3rd Ave sensor. It's junk. Not worth looking at. At 3:30
>it read 12 mph while I planed off from the beach (which takes 18 mph).
>I don't think any amount of correction will fix it because it is
>sometimes beyond the windline, but usually not.

I actually find the 3rd Av. sensor useful If I use the folllowing rule in W
or WNW winds:

If it reads under 12, it usually is not sailable

at 13, there is a 50 - 50 percent chance of sailable wind

at 14, it is probably sailable on a 5.2 for me (145#)

15 and over, it is almost certainly sailable.

The Coyote sensor gives a better idea of the wind in the channel than the
3rd Av sensor, however.

What we really need is a way to measure the wind directly in the bay. What
COTW should have is one of those new laser doppler velocimeters that some
airports now use to predict windshear. With one of those installed at 3rd
you would get a precise contour map of the winds in the Bay between Coyote
and the San Mateo Bridge - no guess involved. Trouble is, the device costs
upwards of a quarter million dollars.

                                        Pierre St. Hilaire
                                        Interval Research Corp

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