The Sentinel class was a two ship class of scout cruiser

Scout cruiser

A scout cruiser was a type of warship of the early 20th Century, which were smaller, faster, more lightly armed and armoured than protected cruisers or light cruisers, but larger than contemporary destroyers...

 serving with the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

, and consisting of the ships HMS Sentinel

HMS Sentinel (1904)

HMS Sentinel was one of two Sentinel class scout cruisers which served with the Royal Navy. She was built by Vickers Limited, laid down in June 1903, launched on 19 April 1904 and completed in April 1905 at a cost of about £282,000...

 and HMS Skirmisher

HMS Skirmisher (1905)

HMS Skirmisher was one of two Sentinel class scout cruisers which served with the Royal Navy. She was built by Vickers Limited, laid down in July 1903, launched on 7 February 1905 and completed in July 1905 at a cost of about £282,000. She sported a partial turtle deck forward and shorter funnels...

.

History

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

Admiralty

The Admiralty was formerly the authority in the Kingdom of England, and later in the United Kingdom, responsible for the command of the Royal Navy...

’s specification, which was for a cruiser capable of reaching 25 knots, carrying ten 12 pounder guns, eight 3 pounder gun

3 pounder gun

3 pounder gun, 3 pounder, 3-pdr or QF 3-pdr is an abbreviation typically referring to a gun which fired a projectile weighing approximately 3 pounds...

s and two torpedo

Torpedo

The modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...

 tubes. The Sentinel class cruisers were built by Vickers Limited

Vickers Limited

Vickers Limited was a famous British engineering conglomerate that merged into Vickers-Armstrongs in 1927.-Early history:Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor &...

 at Barrow

Barrow-in-Furness

Barrow-in-Furness is an industrial town and seaport which forms about half the territory of the wider Borough of Barrow-in-Furness in the county of Cumbria, England. It lies north of Liverpool, northwest of Manchester and southwest from the county town of Carlisle...

. The others were the Forward

Forward class cruiser

The Forward class was a two ship class of scout cruiser serving with the Royal Navy in World War I, and consisting of the ships HMS Forward and HMS Foresight.-Design:...

, Pathfinder

Pathfinder class cruiser

The Pathfinder class was a two ship class of scout cruiser serving with the Royal Navy in World War I, and consisting of the ships HMS Pathfinder and HMS Patrol....

, Adventure

Adventure class cruiser

The Adventure class was a two ship class of scout cruiser serving with the Royal Navy in World War I, and consisting of the ships HMS Adventure and HMS Attentive.-Design:...

 classes. All eight ships were sometimes known as the Sentinel class, as HMS Sentinel was the first to be laid down, first to be launched and first to be completed. They were both laid down in 1903 and completed in 1905.

The class was designed to lead destroyer flotilla

Flotilla

A flotilla , or naval flotilla, is a formation of small warships that may be part of a larger fleet. A flotilla is usually composed of a homogeneous group of the same class of warship, such as frigates, destroyers, torpedo boats, submarines, gunboats, or minesweepers...

s, to act as scouts, lead attacks and take on enemy destroyers. But new turbine engined

Turbine

A turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work.The simplest turbines have one moving part, a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they move and...

 destroyer

Destroyer

In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...

s 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

QF 4 inch naval gun Mk IV, XII, XXII

The QF 4-inch gun Mk IV was introduced in 1911 as a faster-loading light gun successor to the BL 4 inch Mk VIII gun, and was the main gun on most Royal Navy and British Empire destroyers in World War I.-Mk IV gun:...

. Both ships served during the First World War but were scrapped after the cessation of hostilities.

Ships

• HMS Sentinel
  HMS Sentinel (1904)
  HMS Sentinel was one of two Sentinel class scout cruisers which served with the Royal Navy. She was built by Vickers Limited, laid down in June 1903, launched on 19 April 1904 and completed in April 1905 at a cost of about £282,000...
  
   - launched on 19 April 1904, scrapped in 1923.
• HMS Skirmisher
  HMS Skirmisher (1905)
  HMS Skirmisher was one of two Sentinel class scout cruisers which served with the Royal Navy. She was built by Vickers Limited, laid down in July 1903, launched on 7 February 1905 and completed in July 1905 at a cost of about £282,000. She sported a partial turtle deck forward and shorter funnels...
  
  - launched on 7 February 1905, scrapped in 1920.