The de Havilland Mosquito and the War at Sea

The de Havilland Mosquito had a strange career as an anti-shipping aircraft. That career had three distinct phases, two of which were experimental and of at best limited value, the third of which was more conventional and much more successful. In the first phase, a small number of Mosquitoes were converted to carry a smaller version for Barnes Wallis’s bouncing bomb, designed for use against German capital ships. The second phase saw the Mosquito armed with a massive 57mm Molins gun, for use against U-boats. This at least saw service, and was could claim some sinkings. Finally, the Banff Strike Wing, based in Scotland, conducted a successful campaign against German shipping in Norwegian waters.  

The Highball bouncing bomb was entirely associated with No. 618 Squadron, which was specially formed on 1 April 1943 to use the weapon. It was a significantly smaller version of the bomb used by No. 617 Squadron against the Ruhr dams, designed to be used against German capital ships such as the Tirpitz. A number of B Mk IVs were modified to carry two of the new weapon, and No. 618 spent a year practising how to use the weapon. However, by the time they were ready, their targets had gone. The squadron was then sent to the Pacific, and began to prepare for a carrier borne attack on the Japanese naval base at Truk. Once again, by the time they were ready to attack, the Japanese fleet was gone. The squadron was eventually disbanded without seeing action.

de Havilland Mosquito FB XVIII
de Havilland
Mosquito FB XVIII

A small number of No. 618 Squadron crews did see combat with No. 248 Squadron, using another special weapon. This was the Mosquito Mk XVIII, which carried a single 57mm cannon, designed to destroy U-boats. By 1943 the U-boats had been given anti-aircraft guns, and tended to stop on the surface and fight it out with Allied aircraft.

The Mk XVIII “Tsetse” Mosquito began operations on 24 October 1943. The first attack on a U-boat came on 7 November, the first kill (U-976) on 25 March 1944. However, the cannon was awkward to use and the Mosquito vulnerable to enemy fire on the approach. In June 1944 the Mosquito was first used to drop conventional depth charges. No. 248 Squadron retained its Mk XVIIIs until February 1945, by which time it was part of the Banff wing.

Mosquito attack on Dalsfjord, 23 March 1945
Mosquito attack on
Dalsfjord, 23 March 1945

The Banff wing saw the Mosquito reach its peak as an anti-shipping weapon. At its peak this unit contained seven Mosquito squadrons (Nos. 142, 235, 248, 333 RNWAF, 334 RNWAF, 404 RCAF and 489 RNZAF). Based at Banff, Scotland, this wing's job was to sink German shipping off the coast of Norway. Its chosen weapon was the rocket projectile. The Mosquito could carry eight of these rockets, four under each wing. Initially they used 60-lb semi-Armour-Piercing high explosive rockets, but these did little or no damage to shipping. However, 25-lb solid armour piercing rockets were found to be much more effective. These were capable of punching their way through both sides of a merchant ship. Armed with this weapon the Banff wing became a very effective unit.

 Mosquito Bomber/ Fighter-Bomber Units of World War 2, Martin Bowman. The first of three books looking at the RAF career of this most versatile of British aircraft of the Second World War, this volume looks at the squadrons that used the Mosquito as a daylight bomber, over occupied Europe and Germany, against shipping and over Burma. [see more]  
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How to cite this article: Rickard, J (15 April 2007), The de Havilland Mosquito and the War at Sea,

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