Of the one hundred and twenty five projects undertaken by the Department of Miscellaneous Weapons Development (DMWD) during the course of the Second World War, one in five were adopted by the Admiralty. Three of the twenty five were developed at Birnbeck Pier in Weston-super-Mare, a site which had been requisitioned by the Royal Navy from 1941-45. Of these the most significant was the 'Hedgehog' anti-submarine system.
The problem that needed to be solved, was that convoy escort ships needed to intercept German U-boats quickly so as to attack them before they could dive to a safer depth. 35% of U-boats were visible at the time of the intercept and a further 15% had disappeared no more than thirty seconds before. So, the question arose as to how could intercepting U-boats be made more effective? Royal Navy ships lost precious seconds as they had to get beyond the target to discharge traditional depth-charges from the stern. They also lost sonar contact when the ship was directly above the U-boat.
The Hedgehog, DMWD project (No. 20) was developed and trialled at HMS Birnbeck (as the pier was designated during the Second World War), was a multi-spigot mortar which threw contact fused projectiles in a circular pattern 250 yards ahead of the attacking vessel. Two would be mounted onboard - one on each side of the bow.
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| Hedgehog style mortars - USS Charette, Thessaloniki |
As an aside, Hedgehog style weapons were used for many years after the Second World War. The above photo taken during a trip to the First World War Salonika battlefields shows one of a pair of Hedgehogs onboard what was the USS Charette, an American destroyer which served in thw WW2 Pacific Campaign. The Hedgehogs were still deployed when the ship was decommissioned in 1992, having served with the Hellenic Navy.
Of the 41 Kreigsmarine U-boats sunk in May 1943, fourteen were sunk by convoy escorts using Hedgehog. Such losses contributed to a temporary withdrawal of German U-boats to what Admiral Doenitz described as 'less hazardous areas'.
The effectiveness of the Hedgehog can be seen by comparing the 'kill rate' of this new weapon, with the effect of traditional depth charges. During the second half of 1944, 35 Hedgehog salvos were fired, of which 10 resulted in the destruction of a U-boat. A 28% success rate compared with a 5% success rate for traditional depth charging.
So to what extent were the Wheezers and Dodgers of the DMWD responsible for the development of this highly effective weapon and why was Birnbeck Pier such a big part of the story? The latter question is straightforward, in that the massive tidal reach on the North Somerset coast was ideal for weapons testing. A projectile could be fired from the deck of Birnbeck Pier and, once the tide had receded, the discharged ordnance could be picked up from the muddy foreshore.
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| Rails for ordnance retrieval at Birnbeck |
A female Scientific Officer recalled, in an unpublished memoir, how early methods of retrieval worked.
I visited Birnbeck Pier many times and carried out or helped others to carry out tests of such things as the Hedgehog, firing the spigot mortar fixed on one side of the pier. On account of my sex I was excused the cold, wet, and muddy job of getting the Hedgehogs out of the mud at low tide. I remember being told by Jim Close of an occasion when he was grovelling in the mud and the admiral in charge arrived on an unexpected visit. Close was eventually called out of the mud to greet his official commanding officer. He told me later that he was slightly embarrassed at standing to attention and saluting when dressed in nothing but mud – apart from an entirely invisible loin cloth which was the normal dress for mudlarking!
Later, as can be seen in the photograph above, a trolly and rail system was used. Later still, the testing was carried out on St Thomas's Head where landing craft were used for retrieval. Judging by entires in the diary of civilian contractor, M.J.Smith of Crowe and Green - held in Weston-super-Mare Library - the tests were a major activity from 1942 onwards.
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| Hedgehog Pattern St Thomas's Head - National Archive |
The first part of the question I posed above demands a fuller response. Happily, the answer can be found in the records of a lively debate which was conducted in the early 1960s following the publication of 'The Prof in Two Worlds' a biography of Professor F. A. Lindemann (Lord Cherwell). In his work, the author, Lord Birkenhead', stated that 'The Prof' had to fight hard for the Hedgehog against the Admiralty, who eventually made it into a successful anti-submarine weapon with at least thirty-two kills to its credit.
Goodeve's fulsome response, along with a detailed history of Hedgehog's history, was sent to the Cabinet Office on 21 Feb 1962. The claim that the weapon was developed in the face of resistance from the Admiralty was completely untrue. The Admiralty accepted the scheme from very beginning, and with no hesitation. Furthermore the DMWD remained in charge of the weapon until it was finally handed over for operational deployment.
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| Birth of an idea - the first Hedgehog meeting - Churchill Archive |
In his letter to Roskill, Goodeve said that if anyone could claim ownership of the initial idea, it was Millis Jefferis of the Military Intelligence Research branch. Whilsy many others contributed ideas it was Jefferis, working as DMWD Chief Designer, who was most invested.
In corroboration of this, there is a definitive record of 'the birth' of Hedgehog amongst Goodeve's papers at the Churchill Archive in Cambridge. The description of a spigot mortar with the hand drawn diagram is the work of Jefferis. It was appended to a memo from the Director of Anti-Submarine Warfare to Commander Goodeve of the DMWD. The memo, dated 22 Dec 1940, references a meeting to discuss the use of 'spigot-guns' for anti-submarine purposes. It is interesting to see that Goodeve (or his Secretary) scribbled the name 'Norway' on the memo. It was to be Neville Shute Norway (yes, the well known author) who would take the project forward for the DMWD.
In a talk which I occasionally deliver on behalf of North Somerset Council's Birnbeck Pier Regeneration Project, I use the rather tongue in cheek title 'Wheezers and Dodgers: How the Boffins at Birnbeck Pier helped to Defeat Hitler (1941-45)'. With the phenomonal success of the Hedgehog anti-submarine weapon, I rest my case!
To come - the story of Birnbeck Pier's Squids.
