Increasing LNG Carrier Cargo Capacity
The current cargo capacity of 138,000 cubic meter can be increased substantially when the engineroom bulkhead and the aft cofferdam are moved further aft. Changing the overall length or the draft is not recommended, as some major LNG ports have size restrictions. Changing these parameters would impair the flexibility of the vessel. Gas turbine propulsion will allow a rearrangement of the engineroom, since the gas turbine is much smaller than the steam turbine and its steam boilers.
Moving the ER bulkhead aft from frame 71 to frame 45 extends the cargo hold by 20.8 meter. If the gain in gargo hold length is distributed over the four cargo tanks, an increase of 19,000 cubic meter in cargo capacity can be realised. The advantage of this version of the LNG carrier is that it can accommodate both gas turbine electric and gas turbine mechanical drive. The hull form does not have to be changed, so the redesign costs are minimal.
A total rearrangement of the LNG carrier would yield even better results. Cargo capacity would increase by 24,000 cubic meter over the standard design, while the increase thermal efficiency of the combined cycle gas turbine power plant brings fuel cost down by 40%. Increased propulsion efficiency from the podded drive system would bring fuel consumption down even further. Newbuiding cost can be reduced because of the simplified construction of the aft ship, without complex curves around the propeller boss.