Formidable class battleships

The Formidable class of pre-dreadnought battleships were enlarged versions of the previous Majestic and Canopus class ships, this time using the advantages of Krupp steel and water-tube boilers to improve the protection of the ships rather than their speed.

In the Canopus class ships the increased protection offered by Krupp steel over the Harvey steel used in the Majestic class had been used to reduce the thickness of armour carried, resulting in an increase of speed to 18kts. This was helped by the Belleville water-tube boilers, which offered more power than equivalent older cylindrical boilers for the same weight.

Cleaning funnel on pre-dreadnought battleship
Cleaning funnel on

In the Formidable class ships the armour was increased in thickness so that every part of the ship was better protected than in the Majestics, with many parts carrying the same thickness of armour as on those ships. At the same time the engines were improved to provide enough power to maintain the 18kts achieved by the Canopus class ships.

The main armament of the ships remained the same, with four 12in and twelve 6in guns. This would remain the standard British battleship armament until the King Edward VII class of 1903-1905 introduced 9.2in guns. The 12in guns were mounted on circular barbettes with gun mountings that allowed loading from all positions. One new feature was the use of a working chamber below the guns. Cordite would be lifted from the magazine to this chamber on one hoist, the shells filled here, and then a second hoist used to lift the completed shells to the gun loaders. This was designed to reduce the danger of flash reaching the magazines.

The three ships of the Formidable class were built under the 1897/8 naval estimates, as was HMS Vengeance, the last member of the Canopus class.

The three Formidable class ships served with the Mediterranean Fleet from 1901 to 1908, before returning home, initially to join the Channel Fleet. In August 1914 they formed the 5th Battle Squadron of the Channel Fleet, along with the five very similar ships of the London class. On 1 January 1915 HMS Formidable, while serving with the Channel Fleet, was torpedoed and sunk by U 24 off Portland Bill.

Plans of Formidable and London Class Battleships
Plans of
Formidable and
London Class

Detail from Battle of Scheveningen by Willem van de Velde the Elder
HMS Implacable (1898) at Anchor

The two surviving members of the class were sent to the Dardanelles in 1915. There HMS Irresistible took part in the attempt to force the Dardanelles on 18 March 1915. There she hit a mine and had to be abandoned, sinking later in the day.

HMS Implacable survived to the end of the war. She remained at the Dardanelles, taking part in the Gallipoli landings on 25 April. In the next month she was one of the British ships moved to the Adriatic to support the Italians after her entry into the war. She then served in the East Indies before finishing the war on the Northern Patrol, an important element in the blockade of Germany. 

Displacement (loaded)


Top Speed


Armour – deck


 - belt


 - bulkheads


 - barbettes


 - gun houses


 - casemates


 - conning tower



431ft 9in


Four 12in guns
Twelve 6in quick firing guns
Sixteen 12pdr quick firing guns
Six 3pdr quick firing guns
Four 18in torpedo tubes

Crew complement







HMS Formidable
HMS Implacable
HMS Irresistible

Formidable - A True Story of disaster and courage, Steve R. Dunn. Looks at the full story behind the loss of HMS Formidable, a British battleship sunk by a U-boat on 1 January 1915 while under the overall command of an Admiral who at that point didn’t accept that the submarine posed a threat to his fleet. Sections on why she was lost and who was to blame are balanced by detailed examinations of the fate of her crew, the dependents of those lost with her and the public reaction to her lose to produce a useful account of this naval disaster(Read Full Review)
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British Battleships 1889-1904 New Revised Edition, R A Burt. Magnificent study of the Royal Navy's pre-dreadnought battleships, amongst the most powerful ships in the world when built, but seen as obsolete by the outbreak of war in 1914. Traces the development of the 'classic' pre-dreadnought design and the slow increase in the power of the secondary armament, leading up to the all-big gun ships that followed. [read full review]
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Books on the First World War | Subject Index: First World War

How to cite this article: Rickard, J (1 November 2007), Formidable class battleships ,

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