What Is Freeboard?

Freeboard is the vertical distance from the waterline to the deck edge (gunwale). It is a measure of how high the boat sits above the sea, and it changes with loading: every extra kilogram reduces freeboard.

It is the first line of defence against waves: high freeboard means a dry, secure deck; low freeboard means a boat that gets wet in every chop and takes water in rough seas.

Loading and freeboard

• Overloading: Crowding, full tanks and weight on the stern platform eat away at freeboard aft and invite the following sea into the cockpit.

• Uneven loading: Weight piled to one side reduces freeboard asymmetrically; scuppers and side outlets can come down close to the waterline.

• The maker’s limit: Passenger/load limits are a freeboard calculation, not just a seat count; ‘there’s room for us’ is not the same as ‘it can carry us’.

Golden rule for small-boat owners: measure and note your own boat’s freeboard once, both empty and fully loaded. The distance from side outlets (exhaust, scuppers) to the waterline is the most valuable line in that note.