Sentinel was originally planned to be named Inchkeith, which would have subsequently led to the class being known as the Inchkeith class, but Sentinel was renamed before the start of construction.
They were part of a larger order for eight scout cruisers, split between four dockyards, each of which designed their own ships to match the Admiralty’s specification, which was for a cruiser capable of reaching 25 knots (46 km/h), carrying ten 12 pounder guns, eight 3 pounder guns and two torpedo tubes. The Sentinel-class cruisers were built by Vickers Limited at Barrow. The others were the Forward, Pathfinder, Adventure classes. All eight ships were sometimes known as the Sentinel class, as Sentinel was the first to be laid down, first to be launched and first to be completed. Both ships of the class were laid down in 1903 and completed in 1905.
The class was designed to lead destroyer flotillas, to act as scouts, lead attacks and take on enemy destroyers. However, new turbine engineddestroyers left them too slow to fulfill the role. The initial armament was quickly upgraded. Two extra 12-pounder quick firing guns were added, and the 3-pounders were upgraded to 6-pounder guns. Finally, in 1911-12, the 12-pounders were replaced by nine QF 4 inch guns. Both ships served during the First World War but were scrapped after the cessation of hostilities.