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This formula for calculating leeway was in Ocean Navigator #45.

58.5*heel/boatspeed^3=leeway angle

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Date: Wed, 13 Dec 1995 01:12:20 -0500 (EST)
From: "J. Shields" 
Subject: Re: Estimated Position/leeway
Sender: owner-navigation@ronin.com

...

I copied this table into my notebook (from a library book - I think it was
Anapolis Book Of Seamanship, or something like this).  Would you trust
these estimates for leeway? or did I just waste my time copying them down
(also typing them into this posting).  Seriously though - I'm a newbie -
are they kosher?

               LEEWAY Angles (degrees) for Wind Strength / point of sail

BOAT TYPE     FORCE 1-3    FORCE 4-5    FORCE 6-7    FORCE 8-10
              (3-10 knots) (11-21 knts) (22-33 knts) (34-55 knts)
              beat  reach  beat  reach  beat  reach  beat  reach
              ----  -----  ----  -----  ----  -----  ----  -----
shallow-keel   10     5      8      4    12     10    20     12

deep keel       6     4      4      2     6      4    12      6
racer-cruiser

large cruiser
-under power    4     2      6     4     10      8    20     12

-under sail    10     4      8     4     12     12    20     15


There was no explanation as to how these Leeway angles were determined.
I just figured the author knew a lot more than me, and it has been the
only answer I have seen to a pretty important question (in my opinion)
when you are sailing to weather.

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Date: Thu, 14 Dec 1995 00:35:33 +0100
To: navigation@ronin.com
From: J.van.Puffelen@uni4nn.iaf.nl (Jan van Puffelen)
Subject: Re: Estimated Position
Sender: owner-navigation@ronin.com

...

I have always used the formula 8*A/(v2) for leeway whereby A is the angle of
heel in degrees and v the speed in knots. This formula seems to work well
for sailing ships up to 48' or so and for speeds between 3 and 12 knots and
for angles up to 30 degrees. I cannot vouch for anything outside these
boundaries.

   

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