A vessel provided with diving equipment and used for underwater work such as the maintenance and inspection of mobile platforms, pipelines and their connections, well-heads, etc. Today’s DSV is a highly sophisticated vessel that may be of mono, multi-hull or semi-submersible construction. The DSV is fitted with a moonpool – a hole in the middle of the vessel open to the sea – through which divers, remotely-operated vehicles and other equipment is passed to and from the worksite. These vessels may also have A-frame at the stern, used for raising and lowering heavy pieces of equipment, including manned submersibles, into the water.
These vessels can maintain an almost exact position over the worksite during these operations. In order to accomplish this, they have fitted with very sophisticated positioning equipment.