The Erebus class of warships was a class of 20th century Royal Navy monitors armed with a main battery of two 15-inch /42 Mk 1 guns in a single turret. It consisted of two vessels, Erebus and Terror, named after the two ships lost in the Franklin Expedition. Both were launched in 1916 and saw active service in World War I off the Belgian coast. After being placed in reserve between the wars, they served in World War II, with Terror being lost in 1941 and Erebus surviving to be scrapped in 1946.
The Erebus class was designed by Sir Eustace Tennyson-d'Eyncourt, Director of Naval Construction, as an improved version of the previous M29 class monitors. They had a displacement of 8,000 tons (standard) and 8,450 tons (full load), a length of 405 feet (123 m), a beam of 88 feet (27 m), and a draught of 11 feet 8 inches (3.56 m). They were powered by four oil-fired boilers, two shaft reciprocating engines, and had a speed of 12 knots (22 km/h; 14 mph). They had a complement of 204, rising to 315 later.
The main armament consisted of two 15-inch /42 Mk 1 guns in a single turret, which was originally intended for the cancelled battleship HMS Furious. The guns had a maximum elevation of 30 degrees and could fire a shell weighing 1,938 pounds (879 kg) at a range of 23,500 yards (21,500 m). The secondary armament consisted of two single 6-inch (150 mm) guns and four single 3-inch (76 mm) anti-aircraft guns. The ships also had anti-torpedo bulges that were 9 feet (2.7 m) wide.
The ships were built by Harland and Wolff at their yards in Govan and Belfast. Erebus was laid down on 12 October 1915, launched on 19 June 1916 and commissioned in September 1916. Terror was laid down on 26 October 1915, launched on 18 May 1916 and commissioned in August 1916.
The Erebus class was assigned to the Dover Patrol, where their primary duties involved bombarding German targets on the coast of occupied Belgium, particularly at the ports of Zeebrugge and Ostend. They also supported raids and landing operations by British forces.
On 28 October 1917, Erebus was damaged by a remote controlled explosive motor boat near Ostend and had to be towed to Portsmouth for repairs. On the same day, Terror was hit by three torpedoes from German motor torpedo boats near Dunkirk and took severe damage to her bow. She managed to reach Dover under her own power and was repaired at Chatham.
On 23 April 1918, both ships participated in the Zeebrugge raid, an attempt to block the entrance of the port and prevent German submarines from using it as a base. Erebus fired at the mole and the shore batteries, while Terror provided covering fire for the blockships. The raid was only partially successful, as the port remained operational.
In September 1918, both ships supported the Fifth Battle of Ypres by bombarding German positions near Dixmude and Nieuport. They also fired at German railway lines and bridges behind the front lines.
After the end of World War I, both ships were placed in reserve at Portsmouth. They were attached to HMS Excellent, the Royal Navy's gunnery school, and participated in gunnery trials in the 1920s. In January 1934, Terror became the base ship at Sembawang Naval Base in Singapore, where she remained for the rest of the decade. Erebus stayed at Portsmouth until May 1939, when she sailed to Singapore for an extensive refit.
After the outbreak of World War II and the completion of her refit, Erebus was ordered home to Europe in January 1940. She arrived at Plymouth in March and joined Force H, a naval force based at Gibraltar that operated in the Mediterranean and Atlantic. She provided fire support for Operation Collar, an attempt to deliver supplies to Malta and Alexandria in June. She also bombarded French naval bases at Mers-el-Kébir and Dakar after France surrendered to Germany.
In November 1940, Erebus was transferred to the Mediterranean Fleet and joined Terror at Alexandria. They supported the land-based assault of Italian positions in North Africa, bombarding Bardia, Tobruk, Derna and Benghazi. They also defended Malta from Italian air raids and escorted convoys in the Mediterranean.
In January 1941, both ships helped capture Bardia and Tobruk, where they silenced several Italian coastal batteries and destroyed several tanks and vehicles. They also supported the advance of the British Eighth Army along the Libyan coast.
In February 1941, both ships were sent to Benghazi to defend the port from German air attacks. On 22 February, Terror was hit by two bombs from a Luftwaffe Junkers Ju 88 bomber and caught fire. She was towed out of the harbour by the destroyer HMS Decoy, but was hit by another bomb and a mine on 23 February. She was abandoned and scuttled off the coast of Libya in the early hours of 24 February. Most of her crew were rescued by the minesweeper HMS Fareham and the corvette HMS Salvia.
Erebus continued to operate in the Mediterranean until June 1941, when she returned to Britain for a refit at Chatham. She rejoined Force H in September and participated in Operation Halberd, another convoy to Malta. She also bombarded Cherbourg and Le Havre in support of Operation Jubilee, a raid on Dieppe in August 1942.
In June 1944, Erebus participated in the invasion of Normandy as part of Task Force O off Omaha beach. She fired at German strongpoints and artillery positions, as well as providing fire support for advancing Allied troops. She remained off the coast of France until September, when she returned to Britain.
Erebus spent the rest of the war in reserve at Portsmouth. She was sold for scrap in July 1946 and broken up at Inverkeithing.
The Erebus class monitors were powerful and versatile warships that served in both world wars. They proved their value as shore bombardment vessels, supporting land operations and raids by British forces. They also defended vital ports and convoys from enemy attacks. They were among the last monitors to be built and used by the Royal Navy, and their legacy lives on in naval history.