Humber class monitors

The Humber class monitors were originally ordered by Brazil to serve on their rivers. Shallow draft monitor had not been built for the Royal Navy, as they could play no part in the main battle fleet, and foreign examples had been designated as Coastal Defence Vessels, but in 1914 it was quickly realised that they were exactly what was needed for operations off the Belgian coast.

Accordingly, on 3 August 1914, at the start of the First World War these three ships were purchased by the British Government. By August 1914 all three ships were already complete, but the Brazilian government had not paid for them, and so they had remained at Barrow. They had two big advantages as coastal attack vessels. Firstly, they could get much closer inshore without any danger of running aground, and secondly the loss of a 6in monitor would have been much less serious than the loss of a 6in cruiser. This would be even more the case with later classes of monitors, armed with battleship guns.

The Humber class monitors began the war armed with two 6in guns mounted in a single twin turret and two 4.7in howitzers on the quarterdeck. During the war Mersey and Severn were rearmed with two single 6in gun mountings, after their original guns wore out.

All three Humber class monitors took part in the heavy fighting on the Belgian coast during October-November 1914, helping fight off the German attacks during the battle of the Yser (18 October-30 November 1914).

In early 1915 all three were sent to the Mediterranean, a very difficult journey for ships of such shallow draft, capable of being blown sideways in a strong wind. HMS Humber reached Gallipoli in June 1915, taking part in the fighting there, before becoming a guard ship. HMS Severn and HMS Mersey were diverted from the Mediterranean to the coast of East Africa, to take on the German cruiser Königsberg. She was hiding in the Rufiji delta, in water too shallow for British cruisers to reach her. Between 6 and 11 July 1915 the two monitors reduced the Königsberg to a burning wreck. Both ships then remained on the east African coast until 1918.

By October 1918 all three monitors were back in the Mediterranean, at Mudros, passing through the Dardanelles at the end of the war. All three were sold off by 1920.

Displacement (loaded)


Top Speed




Armour – belt


 - bulkheads


 - barbette


 - turret face



266ft 9in

Armaments as built

Two 6in guns
Two 4.7in howitzers
Four 3pdr guns
Six 7mm Hotchkiss machine guns

Crew complement






Ships in class

HMS Severn
HMS Humber
HMS Mersey

Books on the First World War | Subject Index: First World War

How to cite this article: Rickard, J (26 October 2007), Humber class monitors ,

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