Deck Cargo

Deck cargo is cargo stowed on the open weather deck of a vessel, exposed directly to the sea environment including spray, rain, green water, and ultraviolet radiation. It is carried because it is too large to fit in holds, because it is inert gas incompatible with hold cargoes, or because the vessel's hold capacity is fully committed. SOLAS Chapter VI and the CSS Code impose additional securing requirements on deck cargo because it is subject to greater dynamic forces and has no shelter from shipping seas. The Cargo Securing Manual specifies enhanced lashing arrangements and load factors applicable to deck cargoes. Typical deck cargoes include steel pipes, timber baulks, large machinery, project cargo on trailers, and containers on the weather deck of container ships. The chief mate ensures that deck cargo stowage does not obstruct lifeboat access, firefighting equipment, or emergency escape routes. Freeboard considerations are critical: SOLAS and the Load Line Convention impose restrictions on deck cargo that reduces the effective freeboard, as loss of freeboard reduces reserve buoyancy. The OOW inspects deck cargo lashings at regular intervals during the voyage, particularly after heavy weather, and records lashing condition in the cargo log. Green water shipping over the bow can apply enormous forces to deck cargo, and early reduction of speed may be necessary in severe conditions to protect the securing arrangement.