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Encyclopedia of Marine and Energy Technology

High heat tanker BITFLOWER


According to Significant Ships of 2003

BITFLOWER has been designed to transport molten bitumen, hot pitch, and related products of transportation temperatures up to 250°C. The double-skin hull surrounds two cargo holds with a cargo tank block installed in each of them. They are constructed of semi-rigid steel and placed on composite supports on the tanktop, which allows free movement under the influence of thermal expansion, and reduces heat transmission from the tanks to the doublebottom structure. Similarly, the entire piping system is flexibly mounted so that expansion can be compensated for without the need for bellows joints. All the outside surfaces of the blocks are insulated with a two-layer system of mineral wool, partly sheeted with steel.

Cargo is handled from a central pumproom located between the holds, using two Bornemann hydraulically-operated pumps having a maximum capacity of 500m3/h. They can draw cargo from each tank and deliver it through the cargo system to the two deck crossover lines. Filling lines link with this system, and the interconnection between suction and drop lines allow the circulation and cargo trimming between tanks. Two grades can be loaded or discharged from the tanks simultaneously. Loading/unloading systems are remotely controlled from a cargo control room, with Saab monitoring equipment measuring cargo, ballast and bunker tank temperatures, pressures and levels, and linked to a loading computer indicating stress and stability information.

Cargo heating is accomplished by two 1150kW boilers located in the engine room. They burn heavy fuel and raise, to 290°C, the temperature of the diathermic oil medium used to maintain the viscosity of the cargo at required levels. A secondary system heated by an exhaust-gas boiler, provides fluid at 180°C to serve bunker tanks, and supply auxiliary equipment and domestic users.

BITFLOWER features a Wärtsilä Propac machinery installation incorporating a 6L38B main engine, a reduction gearbox with Vulkan flexible couplings, and a CP propeller. The engine output is 4350kW at 600rev/min, with speed reduced by the gearbox to 155rev/min at the propeller. Electrical power is supplied from a 700kW PTO connected to a Stamford alternator, and three 700kW diesel-driven sets having Volvo prime movers. The shaft alternator is designed to serve as an auxiliary propulsion source, with a power-take-in (PTI) enabling the alternator to drive the propeller through the gearbox.

Length, oa: 114.60m, Length, bp: 108.90m, Breadth, mld: 16.45m, Depth, mld: 9.85m, Draught design/maximum: 6.00/6.70m, Deadweight design/maximum: 5268/6384dwt, Gross tonnage: 4890, Main engine MCR: 4530kW, Service speed at 85% MCR: 15 knots.