Combined product/LPG carrier STENA CARIBBEAN
According to The Motor Ship December 2002
This wide-beam/shallow-draught vessel was designed for operation in the very sensitive waters of the Caribbean archipelago, loading and unloading in restricted waters, even direct to beaches using floating hose pipes. Meeting the stringent environmental requirements has heavily influenced the design. In addition to a double-hull configuration, the ship has been fitted with a pair of azimunthing thrusters which, together with the 650kW bow thruster, provides an exceptionally high degree of manoeuvrability enabling the vessel to turn within her own length.
STENA CARIBBEAN is the first vessel built for Stena that incorporates a diesel-electric propulsion system and azimuthing thrusters. The prime movers consist of two Wärtsilä medium-speed 6R32LND diesel engines, each with an output of 2220kW at 720 rpm. They drive two Siemens generators capable of producing 2500kVA each. Auxiliary generators consist of two Wärtsilä 4L20C diesels with a 630kW output at 900rpm and each coupled to a 750kVA Siemens generator. An emergency backup power supply is provided by a high-speed MAN D2688TE diesel providing a power supply of 200kW at 1800rpm and generating 200kVA through a Stamford generator. Siemens also provided a very sophisticated electrical power handling system, which represents the state-of-the-art in power load management.
The vessel can carry 17 segregations of oil product cargoes in conventional tanks, with a total capacity of 12,540m3 . At the same time she has the ability to transport LPG cargoes in two 640m3 fully-pressurised cylindrical deck tanks. The cargo tanks are epoxy-coated and are fitted with heating coils served by deck-mounted manifold valves and 16 deepwell pumps. This enables the vessel to achieve quick turnarounds in port.
Much of the LPG equipment was supplied by Wärtsilä Hamworthy KSE and included the tanks, all valves and instruments, a cargo heat exchanger, and two four-stage centrifugal LPG cargo pumps, each with capacity of 100m3/h at 10 bars. Additionally, the ship is fitted with a floating discharge hose of 500m length with a storage drum. Designed to load fully refrigerated LPG at – 48°C, the containment system is fully pressurised so there is no need for onboard reliquefaction as LPG is discharged at ambient temperature and corresponding pressure.
Length, oa: 120.48m, Length, bp: 117.10, Breadth mld: 23.80m, Depth mld: 9.50m, Draught design/scantling: 6.10/6.53m, Deadweight design/scantling: 8600/9996dwt, Lightweight: 4733 tonnes, Service speed: 13.0 knots, Cargo capacity: 12,375m3.