A pipelay vessel is a marine vessel used to construct subsea infrastructure. It serves to connect oil production platforms to onshore refineries. To achieve this, a typical pipelay vessel carries a heavy lifting crane used to install pumps and valves, as well as equipment to lay pipes between the subsea structures.
Lay methods include J-lay and S-lay, and may be spool-lay or welded lengthwise. Pipelay vessels use dynamic positioning systems or moorings to maintain the correct position and speed while laying pipes.
Recent advances have been made, with pipes being laid at depths greater than 2,500 metres (8,200 ft).
The term pipelay vessel or pipelayer refers to all vessels capable of laying pipes on the ocean floor. It may also refer to "dual-purpose" vessels. These vessels are capable of laying pipes on the ocean floor in addition to their primary work. Examples of dual-purpose pipelay vessels include barges, modified bulk carriers, modified drillships, and semi-submersible pipelay vessels, among others.
A number of national oil companies own and operate pipelay barges for offshore oil projects. HYSY 202 was the first pipelay barge built in China.
