Molten sulphur/bitumen tanker FS CHARLOTTE
According to the Significant Ships of 2006
Designed by Delta Marine, of Istanbul, the 11,000dwt combined molten suplhur and bitumen tanker is one of only very few vessels of this type in service worldwide. FS CHARLOTTE is a single-decked, single-screw tanker, with a double bottom and double skin, and has a total of 11 cargo tanks and two slop tanks. Six of the cargo tanks are designed to carry molten sulphur (1.80t/m3) at 180°C and five to carry bitumen (1.30t/m3) at 250°C. The cargo tanks are fully independent of the hull structure and mounted on special supports, to allow for expansion of the cargo at high temperatures. The Ulepsi tank support system from the Dutch company Beele Engineering was selected for the vessels.
Each of the cargo tanks, which can expand up to 80mm, weighs around 400t. The cargo discharge system is based around four Bornemann hydraulic pumps in two separate rooms. Two pumps each have a capacity of 400m3/h, for bitumen, and two are rated at 337m3/h for molten sulphur. Considerable attention also had to be paid to the effectiveness of the tank insulation system, so that in the event of any technical problems, the cargo temperature can be maintained sufficiently to keep the cargoes liquid, so that they can still be pumped ashore. The daily cargo heat loss, in the event of a heating system failure, is calculated to be only 1°C.
The tanker’s classification covers an extensive list of requirements from Bureau Veritas, including those for vibration and noise, and the structure has additionally been analysed to comply with BV Veristar notation.
The propulsion plant has an output of 5400kW at 500 rev/min. The transmission is taken through a reduction gearbox to a CP propeller of 4400mm diameter, turning at 150 rev/min. Three 750kW heavy-fuel-burning diesel generators are installed, and heat for all cargo and domestic services is generated by two thermal oil boilers and an economizer.
Length, oa: 129.00m, Length, bp: 123.90m, Breadth, mld: 22.00m, Depth, mld: 12.50m, Draught design/maximum: 7.80/8.20m, Deadweight design/maximum: 11,500/12,500dwt, Gross tonnage: 9416, Propulsion power: 5400kW, Service speed at 85% MCR, 20% sea margin: 14.00 knots.