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Old 04-08-2008
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Assuming a typical boat with a hullspeed of 8 knots (static waterline = 36.6 feet) you could expect the following:

Beam reaching (90 degrees true) 10kts wind true:
Boatspeed- 5 knots, Ap wind- 11.2 kts, Ap Dir 64 degrees off bow

Beam reaching (90 degrees true) 15kts wind true:
Boatspeed- 7 knots, Ap wind- 16.5 kts, Ap Dir 65 degrees off bow

Beam reaching (90 degrees true) 30kts wind:
Boatspeed- 8 knots, Ap wind- 31,1 kts, Ap Dir 75 degrees off bow

Broad reaching (135 degrees true) 10kts wind true:
Boatspeed- 5 knots, Ap wind- 7.3 kts, Ap Dir 106 degrees off bow

Broad reaching (135 degrees true) 15kts wind true:
Boatspeed- 7 knots, Ap wind- 11.2 kts, Ap Dir 109 degrees off bow

Broad reaching (135 degrees true) 30kts wind true:
Boatspeed- 8 knots, Ap wind- 25 kts, Ap Dir 122 degrees off bow

Of course those numbers are dependent on your SA/D and L/D. The boatspeed numbers assume an SA/D around 16-17 and a L/D Under 200. A higher SA/D or lower L/d would yield a higher speed through the water at 10 knots of wind and at the 30 wind range. There would be little impact at the 15 knot range.

And I agree that tying yarn or taping cassette tape to your shrouds at eye level helps provide a sense of the apparent wind direction. You don't need to buy teletales.

Jeff

Last edited by Jeff_H; 04-08-2008 at 05:35 PM.
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