Bay Class Landing Ship - Design

Design

The Bay class is certified as a Class 1 Passenger Ship, with design similarities to ro-pax ferries. The design is based on the Royal Schelde Enforcer, a joint project between the Dutch and Spanish resulting in the Rotterdam class and Galicia class amphibious warfare ships. The main difference is that the British ships have no helicopter hangar. The ships were originally designated "Auxiliary Landing Ship Logistics" or ALSL, but this was changed in 2002 to "Landing Ship Dock (Auxiliary)" or LSD(A), better reflecting their operational role and bringing them into line with the NATO designation for the Royal Schelde vessels.

The Bay class ships have a full load displacement of 16,160 tonnes (15,900 long tons). They are 579.4 feet (176.6 m) long, with a beam of 86.6 feet (26.4 m), and a draught of 19 feet (5.8 m). Propulsion power is provided by two Wärtsilä 8L26 generators, providing 6,000 horsepower (4.5 MW), and two Wärtsilä 12V26 generators, providing 9,000 horsepower (6.7 MW). These are used to drive two steerable azimuthing thrusters, with a bow thruster supplementing. Maximum speed is 18 knots (33 km/h; 21 mph), and the Bay class ships can achieve a range of 8,000 nautical miles (15,000 km; 9,200 mi) at 15 knots (28 km/h; 17 mph). The ships were designed to receive an armament of two Phalanx CIWS, two manual 30 mm DS30B cannon and various small arms, but the exact weapons fit varies within the class.

In British service, the everyday ship's company consisted of 60 to 70 RFA personnel, with this number supplemented by members of the British Armed Forces when the ships are deployed operationally. For example, Largs Bay's deployment in response to the 2010 Haiti earthquake saw her sail with a core crew of 70, 40 Royal Logistic Corps personnel for boat- and cargo-handling duties, plus 17 from the Royal Navy and Royal Marines for security and related tasks. Australia operates Choules with a permanent crew of 158 including a Ship's Army Department of 22.

As a sealift ship, each Bay class vessel is capable of carrying up to 24 Challenger 2 tanks or 150 light trucks in 1,150 linear metres of space, with stern- and side-ramp access to the vehicle deck. The cargo capacity is equivalent of 200 tons of ammunition, or 24 Twenty-foot equivalent unit containers. During normal conditions, a Bay class ship can carry 356 soldiers, but this can be almost doubled to 700 in overload conditions. The flight deck is capable of handling helicopters up to the size of Chinooks, as well as Merlin helicopters and Osprey tiltrotor aircraft. There is no hangar for long-term embarkation of a helicopter, although a temporary shelter can be fitted to house a Merlin or smaller helicopter. The well dock can carry one LCU Mark 10 or two LCVPs, and two Mexeflotes can be suspended from the ship's flanks. Two 30-ton cranes are fitted between the superstructure and the flight deck. Internal passages are wide enough to allow two fully kitted marines to pass each other.