Saga Dawn Gas Trials Success for LNT Marine
LNT Marine has successfully completed gas trials of its novel LNTA-BOX containment system aboard Saga Dawn, a mid-size LNG carrier due for delivery from China Merchants Heavy Industry (Jiangsu) shipyard.
Saga LNG Shipping and China Merchants Industry Holdings (CMIH) signed a contract for the 45,000m3-capacity LNG carrier in late 2015, with the yard subsequently entering into a license agreement with Singapore’s LNT Marine for the game-changing LNT A-BOX containment system.
Due for delivery in July, the ABS-classed Saga Dawn is based on LNT Marine’s LNT45 design whereas the basic design was developed in cooperation with Sweden’s FKAB . It will be the first vessel to operate a completely new LNG containment system in decades.
The LNT A-BOX system is based on proven technologies, but in a novel patent-protected configuration. The design is based on an independent tank type A as the primary barrier and a full secondary barrier. Design and construction of type A tanks is based on classical ship structural principles and is reasonable to build. In addition, the tank is flexible in shape and geometry, catering for excellent volume utilization, while internal structure mitigates sloshing and eliminates any loading limitations.
The tank itself is not insulated but installed in an insulated cargo space. This means that the insulation is attached to the interior surface of the hold, while a liquid tight barrier is fitted on the inner surface of the insulation acting as the secondary barrier. In between the tank and the secondary barrier is a cold inter-barrier space, which offers direct access for visual inspections and maintenance of both barriers as well as the tank supports.
Since the insulation is not exposed to any static or dynamic loads from the cargo, the insulation material is optimized for thermal performance which means that the LNT A-BOX system can offer market leading boil-off rates (BOR).
LNT Marine has also developed a semi-pressurized LNG fuel tank dubbed LNT Fuel-BO. This is based on the principles of LNT A-BOX but optimized for fuel tank application. The design, which has already received Approval in Principle from classification society ABS, is particularly appealing to containerships and other volume sensitive vessels with large LNG fuel tanks.