Ship-Technology.com brings us this weeks Interesting Ship:
The Self-Sustaining Cellular Reefer Vessel ( Banana Ship ) Dole Chile and her sister vessel, the Dole Columbia, marked a new departure in reefer ship technology. Prior to their delivery, AP Moller’s large containerships were the world’s largest reefer ships with the ability to carry up to 700 refrigerated TEU.
The two Dole self-sustaining fully cellular vessels combine a hatchcoverless configuration, with a record-breaking concentration of perishable cargo carrying capacity. Dole Chile has a capacity of 1,000 40ft containers or 2,000 TEUs. This equates to approximately 2m cbf, making the Dole sisters the largest cold storage vessels in the world.
Dole Chile was built by Howaldtswerke-Deutsche Werft (HDW) in Kiel for Dole Fresh Fruit International, and delivered in 1999. The vessel is deployed primarily in transporting bananas from Costa Rica to the east coast of the USA.
Dole Chile has Germanischer Lloyd classification and flies the Liberian flag.
HDW had previously used the open-top configuration used in the Dole Chile in the building of Norasia’s six fast container vessels. The owner and yard calculated that a similar configuration would be beneficial in the transportation of reefer cargo by speeding up cargo handling and facilitating the dissipation of the considerable heat that is generated by a full load of reefer containers. The temperature in the cargo holds should not exceed 45°C. Heat dissipation from a 40ft reefer container varies from 4kW for deep frozen products (below -20°C) to 26kW for cooling down bananas after loading in equatorial conditions.
The container refrigeration units used on the Dole ships are fitted with both air-cooled and water-cooled condensers, and are connected to the freshwater cooling system by quick couplings.
Certain holds have been prepared specifically to enable reefer containers to be carried under modified atmosphere arrangements to slow the fruit ripening process. The ripening process is slowed by subjecting the cargo to a nitrogen-rich atmosphere. The plant installed on the Dole Chile employs the membrane process for nitrogen generation.
Dole Chile is equipped with two shipboard gantry cranes, each with a carrying capacity of 40t to ensure rapid cargo handling. These raise the vertical centre of the vessel and required careful consideration due to the restricted depths available in many harbours in the area of deployment. The moulded breadth of the vessel, 32.24m, offers some compensation and also makes it easier to carry 40ft containers in the hold. The electro-hydraulic cranes were manufactured by Liebherr to Germanischer Lloyd specifications. Each consists of a central carrying crossbeam on two supports with a travelling trolley lifting system.
Propulsion is provided by a Sulzer 8RTA72U two-stroke diesel engine, producing 23,920kW at 97rpm, directly driving a fixed-blade propeller with a diameter of 6.65m.
The demand for electrical energy is high on the Dole Chile with its all refrigerated payload. This energy is provided by five four-stroke diesels; three Mak 8M32s and two Mak 6M32s, each providing 3,840kW and 2,880kW respectively at 600rpm. Both generators and diesel engines are installed on a joint base frame with elastic mountings. Power for auxiliary operations, such as the reefer containers, is provided by three diesel generators of 4,650KVA and two diesel generators of 3,490kVA. Emergency power is provided by a Caterpillar 3406 DI-TA diesel delivering 320kW at 1,800rpm, driving a 375KVA diesel generator. The generators supply current to a 6.6kV medium-voltage switchboard plant. The energy supply is automatically modified by a power management system depending on the vessel’s load condition. The 6.6kV switchboard plant supplies the bow and stern thrusters, transformers for cold storage container distribution, MA compressor distribution and the 440V main switchboard.
The bow and stern thrusters were manufactured by Brunvoll and have an output of 1,450kW.