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Due to the rise in popularity and demand for liquefied natural gas (LNG) fuels, marine engineering companies have been releasing various new concepts and designs for LNG bunkering vessels. The most recent design released comes from UK-headquartered engineering and design company Houlder Ltd.

Houlder's new LNG bunkering concept vessel

The concept for this vessel is to act as a ship-to-ship or ship-to-shore transfer vessel. It is equipped with a large crane-style transfer arm to deliver LNG fuels to bunker tanks on any style of large ships and shore tanks.

The maximum rate of gas boil-off for this vessel is 0.45 percent. Up to this amount can be used for fuelling a dual-fuel diesel-electric (DFDE) system used in the vessel itself or it may be returned to storage tanks on shore. If there is any boil-off beyond 0.45 percent, the excess is capable of being condensed again and put back into the onboard storage tanks. Gas combustion units are included onboard to eliminate all gas which cannot be re-condensed for storage purposes.

During ship-to-ship transfers, this LNG bunkering vessel is able to assist the larger ship in warming up, gas freeing, gas freeing, and aerating the LNG bunker tanks.

Specifics of the vessel

These are the specific dimensions and information about the bunkering vessel:

- Length: 110 metres
- Length between particulars: 103.2 metres
- Breadth: 18 metres
- Depth: 10 metres
- Draught:5.9 metres
- Deadweight: 2,700 tonnes
- Service speed: 12 knots
- Capacity: 5,000 cubic metres

Propulsion systems

To help it manoeuvre into position, this LNG vessel is made to berth and un-berth without requiring assistance from a tug. It has two azimuth thrusters and bow thrusters. A setup like this gives it an edge in getting around tighter ports.

How this bunkering vessel can be used

As a design concept it is meant for use in sheltered waters, feeding between two LNG terminals, going alongside in ports, and for small satellite facilities. The vessel is good for smaller spaces and tighter fits, despite its larger bunker tank onboard store size.

How does this vessel impact the industry?

LNG bunkering vessel designs don't exist with much variety for the time being. In general, there are small 3,000-cubic-metre vessels which have great manoeuvrability or larger 7,500-cubic-metre vessels which sometimes need tug assistance to appropriately berth and unberth ships.

Houlder's new design for the 5,000-cubic-metre vessel shows it as a medium-sized vessel that can be used in a more versatile role in both large and small ports.