Northern Barrage

1939 1940 1941 1942 1943 1944 1945 The Northern Barrage was the name given to minefields laid by the British during World War II to restrict German access to the Atlantic Ocean.

[1] Conventional mines of the era employed a contact-fuzed explosive charge within a buoyant shell suspended over an anchor attached by a wire rope.

The Royal Navy standard Mk XVII mine inventory available for use at the outbreak of World War II lacked an antenna fuze.

[3] Those depth capabilities suggested the possibility of laying mines along the Iceland–Faeroes Ridge, a submerged mountain range between Iceland and the Faeroe Islands which separates the deeper portions of the Norwegian Sea to the north and the Atlantic Ocean to the south.

The ridge top is less than 500 metres (1,600 ft) below the surface and significantly shallower east of Iceland and on the Faeroe shelf.

Laying the Northern Barrage in waters so far from land was a challenging navigational problem before Global Positioning System information was available.

[4] The first Minelaying Squadron, based at Kyle of Lochalsh (code-named port ZA for secrecy), was formed in June 1940.

Intelligence reports in July indicated that U-boats were using the Faeroes–Iceland passage, so a series of deep anti-submarine fields were laid north-west of the Faeroes.

Portions of the Denmark Strait minefield damaged by ice were relaid with M Mk I moored magnetic mines.

[1] In fog on 5 July 1942 HMS Niger mistook an iceberg for Iceland’s North Western Cape and led six merchant ships of Murmansk to Reykjavík convoy QP 13 into minefield SN72 laid one month earlier at the entrance to the Denmark Strait.

Most of the steel shell has corroded unless protected by burial in anaerobic sediment; but the cast explosive charge may still be intact.