Transport Publication - TP 10038 E (2003)
A proper freeboard is essential for stability. Freeboard is the distance between the water and the working deck of the vessel. If the deck edge goes under the water when the vessel heels, the danger of capsizing is great.
An overloaded vessel will have too low a freeboard. The deck will submerge with even a slight heel. Overloading is a major cause of fishing vessels capsizing.