The Bay class was designed as a replacement for the Round Table-class logistics ships operated by the RFA. The new design was based on the Royal Schelde Enforcer design; a joint project between the Dutch and Spanish resulting in the "Rotterdam"-class and "Galicia"-class amphibious warfare ships. The main difference with the British ships is the lack of a 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. Four ships were ordered; two from Swan Hunter, and two from BAE Systems Naval Ships.