The Pathfinder 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...

 in World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

, and consisting of the ships HMS Pathfinder

HMS Pathfinder (1904)

HMS Pathfinder was the lead ship of the Pathfinder class scout cruisers, and was the first ship ever to be sunk by a torpedo fired by submarine . She was built by Cammell Laird, Birkenhead, launched on 16 July 1904, and commissioned on 18 July 1905...

 and HMS Patrol

HMS Patrol (1904)

HMS Patrol was a Pathfinder class scout cruiser which served with the Royal Navy before and during the First World War. She has been the only ship of the Royal Navy to bear the name HMS Patrol.-Design:...

.

The three funnelled 'scout' cruisers were designed to operate as the lead ships of 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...

 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 but, like other similar ships, were soon outrun by newer classes of destroyers and relegated to secondary duties. The Pathfinders were built by Cammell Laird

Cammell Laird

Cammell Laird, one of the most famous names in British shipbuilding during the nineteenth and twentieth centuries, came about following the merger of Laird, Son & Co. of Birkenhead and Johnson Cammell & Co. of Sheffield at the turn of the twentieth century.- Founding of the business :The Company...

 and had only a partial armoured deck with side armour covering the engine rooms rather than the more usual full length protective deck. Pathfinder was originally to have been named Fastnet but the name was changed before construction was started. The scout cruisers had poor endurance, leading to the loss of the only scout cruiser sunk during the war, HMS Pathfinder. She was so short of coal whilst on patrol that she could only manage a speed of 5 knots making her an easy target for the German submarine U-21

SM U-21 (Germany)

SM U-21 was one of the most famous U-boats to serve in the Imperial German Navy in World War I. She was the first submarine to sink a ship with a self-propelled torpedo. She also sank the British battleships HMS Triumph and HMS Majestic...

 and giving her the distinction of being the first warship sunk by submarine torpedo attack.

Ships

• HMS Pathfinder
  HMS Pathfinder (1904)
  HMS Pathfinder was the lead ship of the Pathfinder class scout cruisers, and was the first ship ever to be sunk by a torpedo fired by submarine . She was built by Cammell Laird, Birkenhead, launched on 16 July 1904, and commissioned on 18 July 1905...
  
   - launched on 16 July 1904 and sunk by 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...
  
  es fired by off the east coast of Scotland
  Scotland
  Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
  
   on 5 September 1914.
• HMS Patrol
  HMS Patrol (1904)
  HMS Patrol was a Pathfinder class scout cruiser which served with the Royal Navy before and during the First World War. She has been the only ship of the Royal Navy to bear the name HMS Patrol.-Design:...
  
   - launched on 13 October 1904, damaged in action against German battlecruiser
  Battlecruiser
  Battlecruisers were large capital ships built in the first half of the 20th century. They were developed in the first decade of the century as the successor to the armoured cruiser, but their evolution was more closely linked to that of the dreadnought battleship...
  
  s which raided Hartlepool
  Hartlepool
  Hartlepool is a town and port in North East England.It was founded in the 7th century AD, around the Northumbrian monastery of Hartlepool Abbey. The village grew during the Middle Ages and developed a harbour which served as the official port of the County Palatine of Durham. A railway link from...
  
  and sold for scrap on 21 April 1920.