Serco Marine Services

In 1976, the former Admiralty Yard Craft Service merged with the Royal Maritime Auxiliary Service to provide Marine Services for the United Kingdom's Naval Service. However, by 1996 Marine Services was put out to commercial tender by the Ministry of Defence Warship Support Agency (now part of the Defence Equipment and Support organisation) which resulted in all tugs, lifting craft and various tenders being operated by Serco Denholm (the joint venture between Serco Group and Denholm Group). The commercial tender awarded to Serco Denholm also included the management of naval bases Devonport, Portsmouth and Clyde. In December 2007, Serco began the flagship £1bn Private Finance Initiative to provide marine services to the Royal Navy for the next 15 years. This contract includes the manning, operation and maintenance of over one hundred vessels and the introduction of around thirty new ones. As a direct result of this, the Royal Maritime Auxiliary Service which had previously provided this role was formally disbanded on 31 March 2008. All vessels formally prefixed RMAS assumed the SD prefix instead. In 2009, Serco (being the larger partner in the joint venture with Denholm) bought out Denholm's share. Since then, all vessels have seen the SD funnel logos replaced with the Serco logo on the vessels superstructure. However the SD prefix has been retained. The service is now known as Serco Marine Services. ==Role==

Serco Marine Services supports the Naval Service and the Royal Fleet Auxiliary (RFA) in both port and deep water operations. In port and UK waters, Marine Services is primarily tasked with berthing and towage activities located at the three main naval bases; Devonport, Portsmouth and Clyde. Other tasks such as coastal logistics (including stores, liquids and munitions) and passenger ferrying is also readily undertaken. Out-of-port operations in UK waters include direct involvement in supporting diving and minelaying training exercises, as well as torpedo recovery. ==Ships==

As of 2025, Marine Services operates more than 90 vessels at six locations in the U.K. at: Portsmouth, Devonport, Falmouth, Clyde and two at Inner Raasay Sound. The Marine Services were also said to maintain a presence in certain overseas territories, including Gibraltar, the Falkland Islands and the British Sovereign Base Areas in Cyprus. However, marine services at the Port of Gibraltar are provided by the Boluda Towage Europe and as of 2021, marine services in the Falkland Islands were provided by the contracted Netherlands Marine Services company Van Wijngaarden. Since the disbandment of the Royal Maritime Auxiliary Service, all vessels carry the ship prefix SD, and continue to do so since Denholm's share was bought out by Serco in late 2009. Vessels currently in service can be recognised by their black hulls with white beading and white-coloured upperworks. The former buff-coloured upperworks which had once been associated with the RMAS are steadily disappearing with the last few vessels due to adopt the new colour scheme in coming years. The largest ship currently in service is SD Northern River. ==See also==