An oil spill recovery vessel (10) is provided that comprises a catamaran bow section (12) with twin hulls between which an oil skimmer unit (11) is arranged for displacement between a lowered, operating, position in oil-polluted water and a raised, non-operational, position clear of the water. Aft of the catamaran bow section (12) is a trimaran main section (13) made up of a central hull interposed between two outer hulls formed by aft continuations of the twin hulls of the catamaran bow section (12); the three hulls of the trimaran main section have conjoined upper portions. A propulsion unit (53) is operative to move the vessel (10) forward at slow speed for skimming operations, and, with the skimmer unit (11) in its raised position, at a fast speed in which the vessel planes on its trimaran main section (13).