The draft of a ship determines the minimum depth of water that the ship can safely navigate.
The draft of the ship is vertical distance between the waterline and the bottom of the keel.
mean draft =
= ((draft at the bow) + (draft at the stern)) / 2
Causes for a change in the draft:
(1) change in ship's weight
(2) change in water depth (tide, other)
Squat refers to an increase in the draft when moving over shallow water due to hydrodynamic effect.
A boat with a shallow draft can travel in shallow waters but may show poor stability due to a higher center of gravity.
A flat bottom boat tends to have a shallow draft since there is no keel.
