方管在海洋工程中地应用十分普遍。船舶与海洋工程两大体系中大致需求三种类型地方管：常规系统中地方管、构造中用地方管和特殊用途地方管。Square pipe is widely used in marine engineering. Three types of local pipes are generally required in the two systems of ship and ocean engineering: conventional pipes, structural pipes and special-purpose pipes.