Rennie's Floating Graving Dock 插畫檔

Vintage engraving from 1862 of Rennie's Floating Graving Dock. A floating drydock is a type of pontoon for dry docking ships, possessing floodable buoyancy chambers and a "U" shaped cross-section. The walls are used to give the drydock stability when the floor or deck is below the surface of the water. When valves are opened, the chambers fill with water, causing the drydock to float lower in the water.