SD Northern River

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.

Her duties involve target towing during naval training exercises, transport of naval equipment, noise ranging and data gathering, as well as serving as a submarine escort. SD Northern River can embark the NATO Submarine Rescue System.

SD Northern River also reportedly specializes in Special Forces (SF) operations, participating, for instance, in Exercise Chameleon 23-1 off the British Sovereign Base Areas in Cyprus in early 2023.