This is how a floating drydock works. A floating drydock is a mobile, U-shaped structure that uses a system of ballast tanks to submerge and lift ships out of the water for maintenance and repairs. They function on the principle of buoyancy and are often used in sheltered harbors or for naval operations that require mobility. How floating drydocks work The process of docking a vessel in a floating drydock is controlled by flooding and pumping out water from its ballast tanks. 1. Submerging the d