Bureau Veritas approves LNG bunkering vessel design

Classification society Bureau Veritas Marine & Offshore has granted approval in principle to the innovative design for a 19,000-cbm LNG bunkering vessel with a GTT membrane-type tank – the ‘Quadelprop’.

The name Quadelprop reflects features in the design and propulsion arrangements to enable high maneuverability and station keeping.

It includes four azimuth (360°) thrusters fitted at each corner of the hull, four dual-fuel generator sets installed in the engine room compartment and complemented by an energy storage system provide power to the ship and in particular to the electric thruster motors, as well as a redundant dynamic positioning (DP) system.

The high precision of the design’s DP system allows Quadelprop to keep position relative to the client ship so that the LNG transfer system is always within a safe working envelope, Bureau Veritas said in its statement.

Thanks to that DP system, ship-to-ship LNG bunkering operations can also be envisaged safely at anchorage and in waiting areas. The absence of mooring requirements with the client ship not only simplifies and shortens the overall duration of the bunkering operation but also allows the bunker ship to immediately move away from the client ship in case of an emergency shut down and disconnection of transfer hoses.

Two LNG bunkering manifolds are provided: at amidships, portside, with large diameter connections allowing a max transfer flow rate of 2.000 cubic meters/h and a stern bunkering manifold with smaller diameters allowing a transfer flow rate of 250 cbm/h. The starboard side amidships manifold is dedicated to LNG loading at a terminal and is designed for high loading flow rate

The vessel is particularly adapted to coastal navigation and port operation.

Bespoke technical consultancy Marinnov developed the design with engineering support from ship designer Marine Assistance.

The ship is designed to carry LNG, under a maximum pressure of 0.7 barg in two identical membrane-type tanks. The work has involved a close collaboration with Gaztransport & Technigaz (GTT) and Air Liquide for the optimized solution adopted combining ant insulation system of the LNG cargo tanks using the Mark III Flex technology and a sub-cooling unit type TBF-700 providing the vessel with LNG and vapor handling system covering the whole spectrum of the intended cargo operations and services to clients, Bureau Veritas said.