OSSA LNG
Carrier library
Conventional Ocean-Going LNG CarrierConventionalEducational data

Moss-type (spherical) LNG carrier

Self-supporting spherical tanks, instantly recognisable on the horizon.

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Class overview

Moss Rosenberg carriers store LNG in self-supporting aluminium spheres that carry their own structural loads independently of the hull. The design is highly tolerant of partial filling, which makes it forgiving in heavy seas and attractive for trades with frequent part-cargo operations.

Classification

Operational role
Conventional Ocean-Going LNG Carrier
Containment system
Moss / Spherical Self-Supporting Type B
Tank geometry
Independent spheres
Capacity class
Conventional — indicative: approximately 125,000–180,000 m³
Propulsion options
Steam turbine · DFDE / TFDE
BOG management
BOG as fuel · Gas combustion unit

Key systems

ContainmentIndependent aluminium spheres with an equatorial skirt transferring load to the hull
InsulationPolyurethane foam panels applied to the outer sphere surface
Cargo handlingSubmerged cargo pumps with a central vapour dome per tank

Operational environment

Long-haul ocean trades, frequently with part-cargo operation and multi-port itineraries.

Safety and operational considerations

  • Independent tanks are designed on a leak-before-failure basis, with defined inspection access to the containment boundary.
  • Cargo operations follow tank-specific cooldown and filling procedures to limit thermal stress.
  • Large above-deck tank covers affect visibility lines and wind-exposed area during manoeuvring.

Strengths

  • No filling-level restrictions, so partial cargoes are routine
  • Leak-before-failure tank design with excellent structural monitoring
  • Long, proven service record across four decades of trading

Considerations

  • Lower volumetric efficiency than membrane hulls of similar length
  • Large above-deck profile reduces visibility and increases wind load

Technical information

Status
Educational overview — editorial review required
Seeded educational summary awaiting editorial and technical review.
Last reviewed
15 September 2026
Source status
Sources pending editorial review.

Technical parameters are indicative and may vary by vessel design, generation, shipyard, operator and intended service.