An LNG carrier transports liquefied natural gas (LNG) — natural gas cooled to approximately -162°C, at which point it becomes liquid and occupies roughly 1/600th of its gaseous volume, making bulk sea transport practical.
Cargo Containment Systems
- Membrane type — a thin, flexible membrane containment system supported by the ship’s hull structure, insulated to maintain cryogenic temperatures
- Moss type — spherical, self-supporting tanks, visually distinctive (the large dome-shaped tanks characteristic of some LNG carriers)
Why LNG Carriers Are Specialized
- Cryogenic temperatures require highly specialized insulation and materials resistant to extreme cold embrittlement
- Boil-off gas management — some LNG naturally vaporizes during the voyage; modern vessels often use this boil-off gas as fuel for propulsion
- Extensive safety systems — gas detection, emergency shutdown systems, and specialized firefighting capability given the flammability of the cargo
Career Path
LNG carriers require additional specialized training beyond standard tanker familiarization, given the unique cryogenic cargo-handling systems — this specialization commands premium pay in the industry due to the additional expertise required.
Exam Relevance
While general tanker principles apply, LNG-specific cargo handling requires dedicated specialized training beyond the standard deck/engine officer competency exam syllabus.