The Admiralty Yard Craft Service was the civilian service which operated auxiliary vessels for the British Admiralty, mainly in HM Dockyards or the vicinity.
The service operated tugs, harbour ferries, launches, and lighters.
The Yard Craft Service crews answered to the Captain's Department in each dockyard.
The Fleet Coaling Service, renamed the Fleet Fuelling Service sometime between 1914 and 1926, operated harbour and coastal vessels carrying coal and fuel oil to Royal Navy vessels.
Vessels of the Service flew the Blue Ensign defaced by the yellow Admiralty anchor badge.