The Royal Maritime Auxiliary Service(RMAS) was a British Government agency which ran a variety of auxiliary vessels for His Majesty's Naval Service (incl. Royal Navy, Royal Marines) and the Royal Fleet Auxiliary. The service from 2009 has been run by Serco and is known as Serco Marine Services.
His Majesty's Naval Service is the United Kingdom's naval warfare and maritime service. It consists of the Royal Navy, Royal Marines, Royal Fleet Auxiliary, Royal Naval Reserve, Royal Marines Reserve and Naval Careers Service. The term Naval Service should be distinguished from the "UK Naval Services", which consist of the Naval Service and the Merchant Navy. The Naval Service as a whole falls under the command of the Navy Board, which is headed by the First Sea Lord. This position is currently held by Admiral Sir Ben Key. The Defence Council delegates administration of the Naval Service to the Admiralty Board, chaired by the Secretary of State for Defence.
SD Faithful is a Twin Tractor Unit Tug operated by Serco Marine Services in support of the United Kingdom's Naval Service. The ship was formerly operated by the Royal Maritime Auxiliary Service until its disbandment in March 2008. The vessel was originally built for the Royal Maritime Auxiliary Service in 1985.
SD Colonel Templer is an acoustic research vessel, renamed Seaway Endeavour in 2011 after she was sold to a Swedish shipping company. Between 1980 and 2011, she was in the service of the Royal Aircraft Establishment, the Royal Maritime Auxiliary Service and Serco Marine Services in support of the United Kingdom's Naval Service. Before 1980, Colonel Templer was known as MV Criscilla and worked as a stern trawler.
SD Bustler was a Twin Tractor Unit Tug operated by Serco Marine Services in support of the United Kingdom's Naval Service. The ship was formerly operated by the Royal Maritime Auxiliary Service until its disbandment in March 2008.
SD Powerful is a Twin Tractor Unit Tug operated by Serco Marine Services in support of the United Kingdom's Naval Service. The tug, built in 1985, was formerly operated by the Royal Maritime Auxiliary Service until its disbandment in March 2008.
Serco Marine Services is a Private Finance Initiative contract, with Serco Group, to deliver auxiliary services to His Majesty's Naval Service.
SD Nimble was a Twin Tractor Unit Tug operated by Serco Marine Services in support of the United Kingdom's Naval Service. The ship was operated by the Royal Maritime Auxiliary Service until its disbandment in March 2008.
NI Mário Ruivo, previously known as NI Mar Portugal, is a research vessel of the Portuguese Institute of the Sea and the Atmosphere (IPMA).
RMAS Salmaster (A186) was a Sal-Class mooring and salvage vessel. It came under the Royal Maritime Auxiliary Service department of the Royal Navy, and was sold in 2001.
SD Atlas was a tugboat in service with Serco Marine Services at HMNB Portsmouth, where she worked in support of the United Kingdoms Naval Service.
The Felicity-class is a class of water tractors operated by Serco Marine Services in support of the United Kingdom's Naval Service. Historically the vessels were operated by the Royal Maritime Auxiliary Service, disbanded in March 2008.
SD Northern River is a large multi-purpose auxiliary ship operated by Serco Marine Services in support of the United Kingdom's Naval Service and is currently the largest ship operated by Serco Marine Services, both in terms of dimensions and gross tonnage.
SD Victoria is a worldwide support ship operated by Serco Marine Services in support of the United Kingdom's Naval Service, and currently the second largest ship operated by Serco Marine Services, after SD Northern River.
SD Bountiful is an ATD 2909-class tug operated by Serco Marine Services in support of the United Kingdom's Naval Service.
SD Tempest is an ART 8032 class tug operated by Serco Marine Services in support of the United Kingdom's Naval Service. Tempest was ordered specifically to handle the Queen Elizabeth Class aircraft carriers however she performs general harbour towage when not required in her primary role.
RMAS Newton was an underwater research vessel with limited provision for cable laying. She was originally used for sonar propagation trials.
United Kingdom 
United Kingdom 