Marine Loading Arms
The articulated hard arm at an oil, chemical or gas berth: its working envelope, drift alarm bands, the powered emergency release coupling, and movement limits.
A marine loading arm is the articulated steel pipe assembly that connects a terminal’s cargo system to a ship’s manifold, replacing flexible hoses at most oil, chemical and liquefied gas berths. Its swivel joints let it follow the ship as the tide, the draught and the mooring allow the ship to move.
The full article will cover the arm’s working envelope and why it is often a tighter constraint on permitted ship movement than the mooring system itself, the alarm and drift bands that warn as the arm approaches its limits, and the powered emergency release coupling that parts the connection cleanly with the valves closed when the envelope is exceeded or an emergency shutdown fires. It will also cover manifold presentation and the reason a ship’s manifold position drives the fender line at a jetty.
The arm, the emergency shutdown system and the quick release hooks are usually interlocked, so a single event can stop cargo, part the connection and release the ship in sequence.