As well as their role of replenishing warships at sea, support tankers perform the bulk movement of fuels between Ministry of Defense (Navy) depots.

All four were originally designed as commercial tankers and underwent major conversions to bring them up to Royal Fleet Auxiliary standards and equip them for naval support.

Oakleaf was powered by a four-cylinder Burmeister and Wain long stroke oil engine capable of developing 12,250 bhp (9,130 kW) driving a single controllable-pitch propeller.

By September she had arrived on Tyneside for formal docking and inspection, and had approval granted by Lloyd's Register and the Admiralty Ship’s Name and Badge Committee, for her new name.

Captain Bruce Seymour, RFA, took command and Oakleaf sailed for Plymouth, Devon, to store and then to Portland for Basic Operational Sea Training (BOST).

[1] In September 1988 the vessel was involved in humanitarian relief operations in the Caribbean following Hurricane Gilbert,[2] supporting the Royal Navy's Type 21 frigate Active.

[3] In July 1995, the West Indies Guardship, the Royal Navy's Type 42 destroyer Southampton and her support ship, Oakleaf provided assistance following volcanic activity on the island of Montserrat.