Landlocked naval ship superstructures

"The two "hulls" are used to practice replenishment at sea (RAS). The method of transferring stores, personnel and fuel while at sea and moving. The most northern hull is a cross between the deck of a Type 23 Frigate and a Type 42 Destroyer. The second hull is designed to act as a Royal Fleet Auxiliary ship. Ratings undergoing basic training are taught the highly dangerous methods in a safe environment before joining the fleet."