An LNG terminal and an LNG carrier are each useless without the other, and the few metres between them are where a surprising amount of the industry’s engineering attention goes.
Compatibility is decided long before arrival
A ship does not turn up and find out whether it fits. A compatibility study is completed in advance, and it covers more than most people expect.
Berth dimensions. Length overall, beam, draft against available water depth, and the position of the ship’s manifold relative to the jetty’s arms once moored.
Manifold geometry. Height above the waterline, spacing between connections, and flange sizes. Height is the awkward one because it changes throughout the operation: a ship rises as it discharges and settles as it loads, and the arms must accommodate the full range.
Mooring. Line arrangement, bollard positions and loads, and whether the ship’s fittings suit the berth’s.
Transfer rate. The terminal’s pumps and the ship’s ability to accept or deliver at that rate, and the vapour return path that has to handle displaced gas going the other way.
Emergency shutdown. The two systems must be able to talk to each other, which is less trivial than it sounds because several incompatible signalling standards exist.
A mismatch in any of these is not a delay. It is a ship that cannot berth.
The arms
Loading arms are articulated insulated pipes, counterweighted, with swivel joints that let them follow the vessel as it moves with tide, load and weather. A conventional berth has several: some for liquid, at least one for vapour return.
Two features distinguish them from ordinary transfer equipment.
A quick connect and disconnect coupler attaches the arm to the ship’s flange in one operation rather than by bolting, because bolting a dozen flanges by hand at each end of every port call would dominate the schedule.
A powered emergency release coupling sits in the arm and can part it deliberately. Valves on both sides of the coupling close first, so the arm separates with almost nothing released. This is the second stage of shutdown, and it exists for the case where the ship is leaving the berth whether anyone likes it or not.
Emergency shutdown, in two stages
ESD1 stops the transfer. Pumps stop, valves close on ship and shore, and the operation halts in seconds. It can be triggered by either side, automatically by instrumentation, or manually.
ESD2 parts the connection. If the vessel drifts beyond the arms’ working envelope, the couplings release. The sequence is automatic because a ship moving off a berth outruns human reaction.
The link between the two systems is a physical connection made when the ship connects — pneumatic, electric or fibre optic depending on the terminal — and confirming it works is part of the pre-transfer checklist.
Why loading takes as long as it does
Pumping a conventional cargo is roughly twelve hours at typical rates. The port call is longer.
Mooring and connecting come first. Arms have to be purged of air and cooled gradually, for the same reason tanks are cooled gradually. Pre-transfer checks are worked through jointly and signed. Transfer starts slowly, at a reduced rate, until both sides are satisfied, then ramps to full. At the end the arms are drained, purged and disconnected, and the custody transfer measurement is completed and agreed.
A day at the berth for twelve hours of pumping is normal.
Why this constrains the fleet
The compatibility list is why ship classes exist as classes at all. The conventional 174,000 cubic metre size persists because it is close to the largest that most terminals can physically accept, not because it is the largest anyone can build.
It is also why a berth is an asset with a specific customer list. A terminal built for one project’s ships may be unable to take another’s, and adding that capability later means modifying the jetty rather than the ships.
What the data shows
The terminal pages carry what GEM reports: location, capacity, status, ownership. Berth-level detail — arm count, manifold arrangement, maximum vessel size — is not in the tracker and is not shown here, because inventing it would be worse than its absence.
Where the site does speak to physical connection is the proximity link between pipelines and terminals, and that is deliberately labelled as proximity within 25 kilometres rather than as a confirmed connection, for the same reason.