Leigh Light | EPFL Graph Search

Are you an EPFL student looking for a semester project?

Work with us on data science and visualisation projects, and deploy your project as an app on top of GraphSearch.

The Leigh Light (L/L) was a British World War II era anti-submarine device used in the Battle of the Atlantic. It was a powerful (22 million candela) carbon arc searchlight of diameter fitted to a number of the British Royal Air Force's Coastal Command patrol bombers to help them spot surfaced German U-boats at night. Early night operations with the new Air-to-Surface Vessel radar (ASV) demonstrated that the radar's minimum range of about meant that the target was still invisible when it disappeared off the radar display. Efforts to reduce this minimum were not successful, so Wing Commander Humphrey de Verd Leigh hit upon the idea of using a searchlight that would be switched on just when the target was about to disappear on radar. The U-boat had insufficient time to dive and the bombardier had a clear view of the target. Introduced in June 1942, it was so successful that for a time German submarines were forced to switch to charging their batteries during the daytime, when they could at least see aircraft approaching. Germany introduced the Metox radar warning receiver in an effort to counter the combination of ASV and Leigh Light. Metox provided the submarine crew with early warning that an aircraft using radar was approaching. Because the radar warning receiver could detect radar emissions at a greater range than the radar could detect vessels, this often gave the U-boat enough warning to dive. Having expected this, the Allies introduced the centimetric ASV Mk. III radar, regaining control of the battle. Although the German Naxos countered these radars, by this time the U-boat force was already damaged beyond repair. Early air-to-surface radar sets, namely the ASV Mk. II, had an inconveniently long minimum detection range. Thus as the aircraft approached the target, it would disappear off the radar at a range that was too great to allow it to be seen by eye at night without some form of illumination.

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related concepts (11)

Metox radar detector

The R600A Metox, named after its manufacturer, was a pioneering high-frequency radar warning receiver (RWR) used by the German forces on U-boats from 1942-45. It was initially installed to receive signals used by British radars. The Metox was manufactured by a small French company in occupied Paris. It was tuned to receive the signals used by many British radars of the early and mid-World War II era, notably the ASV Mk. II radar used by RAF Coastal Command to attack U-boats. It is not clear whether the design was German or French or both.

Naxos radar detector

The Naxos radar warning receiver was a World War II German countermeasure to S band microwave radar produced by a cavity magnetron. Introduced in September 1943, it replaced Metox, which was incapable of detecting centimetric radar. Two versions were widely used, the FuG 350 Naxos Z that allowed night fighters to home in on H2S radars carried by RAF Bomber Command aircraft, and the FuMB 7 Naxos U for U-boats, offering early warning of the approach of RAF Coastal Command patrol aircraft equipped with ASV Mark III radar.

Leigh Light