Word for the distance from the waterline to the main deck of a boat

What is the word for the distance from the waterline to the main deck of a ship? In other words, the height of the main deck (or gunwale if that has a name) above the water when the ship is at sea.

To understand my motivation, broadly speaking I am interested in the furthest you would fall if you were standing on the main deck and went overboard.

The distance from the waterline to the bottom of the boat is called the draught.

The word you are looking for is freeboard:

In sailing and boating, a vessel's freeboard is the distance from the waterline to the upper deck level, measured at the lowest point of sheer where water can enter the boat or ship.

Source: Wikipedia