Penalties of Heeling

The penalties for heeling in moderate to heavy breeze are:

Weather Helm Develops This happens mainly because the forward driving force of the rig is no longer over the centerline but acting from over the water several feet to leeward. To counteract the tendency that this creates for the boat to screw up into the wind, the helmsman hauls his tiller up to windward and the angled rudder acts as a brake, producing several times as much drag as a straight tiller.

The Rig Loses Power It is often forgotten that the rig becomes appreciably less efficient as it heels, turning more of the forces available for forward motion into the downward acting force already mentioned. Even with a 15 degree of heel there is a fraction less power available to convert into forward motion than when the rig is upright. As the boat heels to over 25 degrees, more power falls off dramatically.

Leeway Increases Even at 10 degrees of heel, leeway increases slightly. At 20 degrees or 25, leeway increases considerably in dinghies, and leeway becomes excessive when this heeling combined with loss of speed, causes the centerboard to stall. This happens particularly easily on boats with fairly small, narrow boards.

Crew Weight Becomes Less Effective When the boat heels, the centers of gravity of the hiking helmsman and crew move closer to the center of buoyancy of the hull, and thus transmit less righting moment to the rig than when upright. Also, as the crew and helmsman are lifted higher above the water, their bodies come into a faster wind stream so drag is marginally increased.

Exposing Freeboard When the boat heels in heavy air, the side of the hull is exposed to more wind-age and considerable drag. The wind catches beneath the hull, inducing greater heel and more leeway.

Shallow Centerboard Depth As the hull heels the centerboards swings upward and is not longer as deep in the water as it can be, resulting in additional leeway.

Reduced Mast Height As the hull heels the mast tilts downward, preventing the sail in general, and specifically its “center of effort”, from being as high off the water as possible and gaining the benefits of higher wind speeds aloft.



-Eric Twiname
Sail, Race, Win
and
-B. Churchill