- Keel
- A keel is an extension on the bottom of a boat which is weighted to provide additional stability.
- Kicking Strap
- The kicking strap is used to control a sails shape. It can be used to tension the boom and thus helps prevent lifting that can cause wind to spill out over the sail.
- Knot
- A boating reference to the nautical speed one nautical mile an hour (originally measured by the number of tied knots in a line being drawn overboard).