Lateral Balance

[Jock-san]

Hi all,

I''d like to hear some of your expert opinions on boat balance for racing, particularly on 30-odd to 40-odd feet cruisers and racers.

All those years ago when I first sailed ( dinghies) we learned to sail the boat as flat as possible. My Glenans sailing manual repeats the same advice for larger sailing craft too, and on the face of it, it makes sense - you picture getting the most power from the sails by keeping them upright.

The exception in this approach is when the wind no longer has the strength to keep the sails full, when better speed can be had by heeling the boat to leeward enough for gravity to keep them in shape.

These days I''ve sailed with a couple of crews on boats either side of 40 feet, who send some or all of the crew to the lee side, in lighter winds but well before the point where the sails begin to hang. We''ll be sailing heeled maybe 15 degrees to leeward in seven or eight knots of wind.

I''ve read (on the boards here ?) how some lee heel can add weather-helm feel in lighter winds and I can see the point in that, but at the same time have been part of a crew that even on an unfamiliar boat, made ''lee weight'' calls without reference to the helmsman, explaining that it was intended to decrease the wetted area of the hull. WRT balance, I know that phrase only from balancing forward, upwind.

Did balance theory change while I was looking the other way ?

At what point do you begin to move people off the windward rail ? Can general rules be laid down for types / ages of design, or does lateral balance vary from hull to hull ?

The boats I have recent race experience on are an Adams 12, a Farr 44, and a Jeanneau Sun Kiss 47.

Regards,

Jock

[paulk]

The preferred angle of heel will be different for each different boats. It will depend, as you suggest, on the amount of "feel" the helmsman is looking for, the amount of wind, and the size and spacing of waves. Each skipper likely has a set of beliefs (as do we all) about the "groove" his boat sails best in. How much of this is conjecture or "feel", and how much is empirical, is anybody''s guess. Hydrodynamics are a fluid science... there''s so much going on with a boat under sail, it''s hard to be sure of much. If you win, you were right. Otherwise, maybe you were still right but something else made you lose. Figuring this out is part of the fun.

[Sailormon6]

When sailing in wind that is so light that it can''t keep your sails full, inducing the boat to heel by moving crew weight onto the lee rail helps keep the boat moving. Gravity causes your sails to hang in the curved shape that drives the boat, instead of hanging limp, like a sheet on a line. Also, moving crew weight forward and to leeward usually reduces the amount of wetted surface. By heeling the boat, the outboard end of the boom is less likely to swing in light air.

It takes a lot of crew weight to heel a big, ballasted boat, but the benefits of heeling more than offset the added weight. If you give the sails a full shape and bear off the wind a bit, you can keep moving when others are losing steerageway.