Keel

The keel has two jobs. As a lateral plane, it resists the sideways push of the wind so the boat moves forward instead of sliding sideways. As ballast, it puts weight very low, often in a bulb at the end of a thin fin, to counter heeling.

On racing monohulls it can be fixed, canting (swinging sideways) or lifting. Keel damage is among the most serious at sea: without it, a monohull capsizes.