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. The barrage stretched from the Orkney to the Faroe Islands and on toward Iceland. Mines were also laid in the Denmark Strait, north of Iceland. [1]
The objective of a defensive minefield is to restrict movement of enemy ships into areas used by friendly shipping. The assumed presence of a minefield may have a morale effect of assumed risk in addition to actually damaging ships attempting to cross the field. In July 1939, before World War II had begun, the possibility of a Northern Barrage between the Orkney Islands and Norway (similar to the North Sea Mine Barrage of World War I) had been considered. Other alternatives were investigated after the occupation of Norway by the Germans in April 1940. [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. Use of such mines against surface ships required the mine to be suspended at a depth no greater than the ship's draft. The ability of a submarine to submerge under that depth would require layers of contact-fuzed mines at differing depths to afford equal probability of destruction. The World War I mine barrage had reduced the number of mines required by using a copper wire antenna with a float to extend it above the mine. A ship's steel hull touching the copper antenna would form a battery and seawater acted as an electrolyte completing a circuit with an insulated copper plate on the mine surface to actuate a detonating relay within the mine. [2]
American Mk 6 mines had been used for the deeper water portions of the World War I mine barrage. The Royal Navy standard Mk XVII mine inventory available for use at the outbreak of World War II lacked an antenna fuze. The Mk XVII mine could be suspended at depths as great as 300 feet (91 m) below the surface anchored in water as deep as 6,000 feet (1,800 m). [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. Channels are 850 metres (2,790 ft) deep between the Faeroe shelf and Scotland and in the Denmark Strait between Greenland and Iceland. Mk XVII mines would be laid in the shallower areas while the antenna-fuzed Mk XX mine was under development. Gaps were planned to allow passage of the fleet and convoys. [1]
Maintaining precise records of minefield locations is an important element of defensive minefields, since these minefields are often close to waters traditionally used by friendly shipping. Most defensive minefields had historically been within visual distance of navigational aids establishing precise locations. Laying the Northern Barrage in waters so far from land was a challenging navigational problem before Global Positioning System information was available. Much of the preparatory survey work was completed by the survey vessel HMS Scott. Scott later operated with the minelayers placing the deep water minefields from the spring of 1942 until minelaying was discontinued in the autumn of 1943. Scott helped establish the boundaries of previously laid adjacent minefields so the minelayers could minimize un-mined gaps without accidentally straying into previously mined areas. [4]
The first Minelaying Squadron, based at Kyle of Lochalsh (code-named port ZA for secrecy), was formed in June 1940. Five fast and modern cargo liners were requisitioned from civilian service, but the conversion to auxiliary minelayers HMS Agamemnon, Menestheus, Port Napier, Port Quebec and Southern Prince was not completed until October. Arrival of Town-class destroyers from the Destroyers for Bases Agreement provided necessary escorts for the minelayers. The first minelaying mission left port ZA on 18 October 1940, and 10,300 conventional contact mines were laid at the southern end of the Iceland–Faeroes Ridge before the end of the year. [1]
The Mk XX mine became available in early 1941 with a copper wire antenna extended 60 feet (18 m) above the explosive casing by a buoyant float and a lower antenna extending 74 feet (23 m) below the casing. [3] Minelaying progressed with new fields laid north and south of the Faeroes and in the Denmark Strait using Mk XX mines wherever its 134 feet (41 m) depth coverage would reduce the number of mines required. Additional safety measures were required for the new mines after Menestheus was damaged by detonation of a drifting Mk XX mine on 6 February 1941. 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. [1]
1942 minelaying used a new Mk XXII mine with a buoyant copper tube upper antenna replacing the solid copper wire and buoyant float of the Mk XX mines. [3] The minelaying cruiser HMS Adventure laid the first M Mk I moored magnetic mines and became a regular participant in first Minelaying Squadron missions from May through November 1942. Portions of the Denmark Strait minefield damaged by ice were relaid with M Mk I moored magnetic mines. [1]
| Date | Operation | Location | Minelayers |
|---|---|---|---|
| October 1940 | SN3 | Iceland-Faeroes Ridge | HMS Agamemnon, Menestheus, Port Napier, Port Quebec and Southern Prince |
| November 1940 | SN11 | southern Iceland-Faeroes Ridge | Agamemnon, Menestheus, and Port Quebec; Port Napier exploded before leaving port ZA |
| December 1940 | SN10A | southern Iceland-Faeroes Ridge | Agamemnon and Menestheus |
| January 1941 | SN6 | south of Faeroes | Agamemnon, Menestheus, Port Quebec and Southern Prince |
| January 1941 | SN65 | south of Faeroes | Agamemnon, Menestheus, Port Quebec and Southern Prince |
| February 1941 | SN7A | Port Quebec and Southern Prince; Menestheus damaged by a drifting Mk XX mine and towed back to port ZA by Agamemnon | |
| February 1941 | SN7B & SN68A | Agamemnon, Port Quebec and Southern Prince | |
| March 1941 | SN4 | Iceland-Faeroes Ridge | Agamemnon, Menestheus, Port Quebec and Southern Prince; Agamemnon damaged by collision with HMS Castleton on return voyage |
| April 1941 | SN71 | Denmark Strait | Menestheus, Port Quebec and Southern Prince |
| April 1941 | SN8 | Denmark Strait | Agamemnon, Menestheus, Port Quebec and Southern Prince |
| May 1941 | SN9 | Iceland-Faeroes Ridge | Agamemnon, Menestheus and Port Quebec |
| June 1941 | SN64 | North Rona area | Agamemnon and Menestheus |
| June 1941 | SN66 | Agamemnon and Menestheus | |
| June 1941 | SN70B | Iceland-Faeroes Ridge | Agamemnon and Menestheus; collision between escorts HMS Kenya and Brighton |
| July 1941 | SN67A | Iceland-Faeroes Ridge | Agamemnon, Menestheus and Port Quebec |
| July 1941 | SN12A | northwest of Sula Sgeir | HMS Teviot Bank |
| August 1941 | SN22B | Butt of Lewis | Agamemnon |
| August 1941 | SN70A | Butt of Lewis | Menestheus, Port Quebec and Southern Prince; Southern Prince torpedoed by U-652 on return trip |
| September 1941 | SN61 | North Rona area | Agamemnon |
| September 1941 | SN23 | Butt of Lewis | Port Quebec |
| October 1941 | SN24 | Butt of Lewis | Port Quebec |
| October 1941 | SN83A | northern Faeroes gap | HMS Welshman, Menestheus and Port Quebec |
| November 1941 | SN83B | northern Faeroes gap | Menestheus and Port Quebec |
| November 1941 | SN25 | northwest approaches | Menestheus |
| January 1942 | SN26 | Butt of Lewis | Agamemnon |
| February 1942 | SN5B | Faeroes fjords | Agamemnon and Menestheus |
| February 1942 | SN84 | Iceland-Faeroes Ridge | Agamemnon, Menestheusand Port Quebec |
| February 1942 | SN85 | Iceland-Faeroes Ridge | Agamemnon, Menestheus, Port Quebec and Southern Prince |
| March 1942 | SN81 | Iceland-Faeroes Ridge | Agamemnon, Menestheus, Port Quebec and Southern Prince |
| March 1942 | SN87 | Iceland-Faeroes Ridge | Agamemnon, Menestheus, Port Quebec and Southern Prince |
| April 1942 | SN88 | Iceland-Faeroes Ridge | Agamemnon, Menestheus, Port Quebec and Southern Prince |
| May 1942 | SN3A | Faeroes shelf west of Orkney Islands | HMS Adventure, Agamemnon, Menestheus, Port Quebec and Southern Prince |
| June 1942 | SN72 | Denmark Strait | Adventure, Agamemnon, Menestheus, Port Quebec and Southern Prince |
| June 1942 | SN3B | Faeroes shelf west of Orkney Islands | Adventure, Agamemnon, Menestheus, Port Quebec and Southern Prince |
| July 1942 | SN3C | Faeroes shelf west of Orkney Islands | Adventure, Agamemnon, Menestheus, Port Quebec and Southern Prince |
| July 1942 | SN82 | Iceland-Faeroes Ridge | Adventure, Agamemnon, Menestheus, Port Quebec and Southern Prince |
| August 1942 | SN73 | Denmark Strait | Adventure, Agamemnon, Menestheus, Port Quebec and Southern Prince |
| September 1942 | SN89 | Iceland-Faeroes Ridge | Adventure, Agamemnon, Menestheus, Port Quebec and Southern Prince |
| September 1942 | SN65A | Iceland-Faeroes Ridge | Adventure, Agamemnon, Menestheus, Port Quebec and Southern Prince |
| October 1942 | SN3E | Faeroes shelf west of Orkney Islands | Adventure, Agamemnon, Menestheus, Port Quebec and Southern Prince |
| November 1942 | SN3F | Faeroes shelf west of Orkney Islands | Adventure, Agamemnon, Menestheus, Port Quebec and Southern Prince |
| March 1943 | SN90A | west of Iceland | Agamemnon, Menestheus and Port Quebec |
| May 1943 | SN111A | off Iceland | Agamemnon, Menestheus and Port Quebec |
| May 1943 | SN123A | Butt of Lewis | Agamemnon lays experimental field of modified M Mark I Mines |
| May 1943 | SN123B | Butt of Lewis | Agamemnon, Menestheus and Port Quebec lay experimental field |
| June 1943 | SN123C | Butt of Lewis | Agamemnon, Menestheus and Port Quebec lay experimental field |
| June 1943 | SN222A | southeast of Iceland | Agamemnon, Menestheus and Port Quebec |
| August 1943 | SN74 | Denmark Strait | Agamemnon, Menestheus and Port Quebec |
| September 1943 | SN222B | southeast of Iceland | Agamemnon, Menestheus and Port Quebec |
| September 1943 | SN222C | southeast of Iceland | Agamemnon, Menestheus and Port Quebec |
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. [5] Every ship struck mines. There were no crewmen lost aboard the Soviet freighter Rodina (4441 GRT), [6] the Panamanian-flagged freighter Exterminator (6115 GRT), or the American freighter Hybert (6120 GRT); but 46 civilian crew and 9 Naval Armed Guards died aboard the American Liberty ship John Randolph (7191 GRT) and freighters Hefron (7611 GRT) and Massmar (5825 GRT); [7] and there were only eight survivors of the 127 men aboard Niger. Only Exterminator could be salvaged. [8] The value of the Northern Barrage was questioned following the accident, though new fields were laid south of Iceland, before starting new deep fields on the Faeroes shelf. [1]
The future of the Northern Barrage was discussed by the Admiralty at meetings in January and July 1943. Escorts allocated to protecting the minelayers had created a shortage of convoy escorts. The barrage had proved difficult to maintain [1] and there were no survivors to verify sinking of U-boats by the northern mine barrage; although it may have claimed several whose loss has not been otherwise explained, including U-104 in November 1940, [9] U-702 in March 1942, [5] U-253 in September 1942, [10] U-647 in July 1943 [11] and U-855 in September 1944. [12] The Allies were unaware of these U-boat losses and attributed most of them to Allied ship and aircraft attacks after the Commander-in-Chief of the Home Fleet declared the Northern Barrage "the least profitable voluntary major undertaking of the war". [13]
The programme was cancelled and apart from the laying of an additional field at the entrance to the Denmark Strait, the only minelaying approved was a series of deep fields at the northern end of the Faeroes–Iceland gap. The First Minelaying Squadron was disbanded after laying 92,083 mines. The minefield represented 35 percent of all British minelaying effort during the war. [1] The Northern Barrage had failed to justify its existence and had often been more dangerous to Allied forces than to the Germans. Afterwards more effort was deployed on offensive minelaying by submarines, motor launches and aircraft, which proved far more effective. [1]
Not all of the mines were removed or destroyed during or following the war and unexploded mines have been discovered into the twenty-first century. Most of the steel shell has corroded unless protected by burial in anaerobic sediment; but the cast explosive charge may still be intact. The most commonly used mines included 227 kilograms (500 lb) or 137 kilograms (302 lb) of explosives. TNT was the most commonly used explosive, although it was sometimes mixed with ammonium nitrate (forming Amatol) for economy and with powdered aluminum (forming Minol) to increase underwater damage. [5]
A naval mine is a self-contained explosive device placed in water to damage or destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, any vessel or a particular vessel type, akin to anti-infantry or anti-vehicle mines. Naval mines can be used offensively, to hamper enemy shipping movements or lock vessels into a harbour; or defensively, to protect friendly vessels and create "safe" zones. Mines allow the minelaying force commander to concentrate warships or defensive assets in mine-free areas giving the adversary three choices: undertake an expensive and time-consuming minesweeping effort, accept the casualties of challenging the minefield, or use the unmined waters where the greatest concentration of enemy firepower will be encountered.
A minelayer is any warship, submarine, military aircraft or land vehicle deploying explosive mines. Since World War I the term "minelayer" refers specifically to a naval ship used for deploying naval mines. "Mine planting" was the term for installing controlled mines at predetermined positions in connection with coastal fortifications or harbor approaches that would be detonated by shore control when a ship was fixed as being within the mine's effective range.
The first USS San Francisco (C-5) was a steel protected cruiser in the United States Navy. She was later named Tahoe and then Yosemite, becoming the third US Navy ship to bear the name Yosemite. She generally resembled her predecessor Newark, with a main armament of twelve 6-inch guns.
The North Sea Mine Barrage, also known as the Northern Barrage, was a large minefield laid easterly from the Orkney Islands to Norway by the United States Navy during World War I. The objective was to inhibit the movement of U-boats from bases in Germany to the Atlantic shipping lanes bringing supplies to the British Isles. Rear Admiral Lewis Clinton-Baker, commanding the Royal Navy minelaying force at the time, described the barrage as the "biggest mine planting stunt in the world's history." Larger fields with greater numbers of mines were laid during World War II.
USS Aroostook (ID-1256/CM-3/AK-44) was the Eastern Steamship Company's Bunker Hill converted for planting the World War I North Sea Mine Barrage. Bunker Hill was built in 1907 at Philadelphia, Pennsylvania for passenger service between Boston and New York City. Bunker Hill was one of three sister ships, the others being Massachusetts and Old Colony, delivered as passenger/cargo ships by William Cramp & Sons in 1907. They were among the eight ships acquired by the U.S. Navy in November 1917. Bunker Hill and Massachusetts were converted to minelayers at the Boston Navy Yard. Old Colony was used as a district scout until sent across the Atlantic and turned over to the British in 1919.
HMS Abdiel was an Abdiel-class minelayer that served with the Royal Navy during World War II. She served with the Mediterranean Fleet (1941), Eastern Fleet (1942), Home Fleet (1942–43), and the Mediterranean Fleet (1943). Abdiel was sunk by German mines in Italy's Taranto harbour in 1943. Although designed as a fast minelayer her speed and capacity made her suitable for employment as a fast transport.
HMS Niger was a Halcyon-class minesweeper of the Royal Navy. She was launched in 1936 and was sunk during the Second World War. On 5 July 1942, the vessel sailed into a minefield while escorting Convoy QP 13 and struck one of the mines, later sinking with only eight survivors.
HMS Apollo was an Abdiel-class minelayer of the Royal Navy, the eighth RN ship to carry the name. She served with the Home Fleet during World War II, taking part in the Normandy Landings before being transferred to the British Pacific Fleet. Put into reserve in 1946, she was recommissioned in 1951, serving until 1961, and was sold for scrapping in 1962.
The Yugoslav minelayer Zmaj was built in Weimar Germany for the Royal Yugoslav Navy in the late 1920s. She was built as a seaplane tender, but does not appear to have been much used in that role and was converted to a minelayer in 1937. Shortly before the Axis invasion of Yugoslavia in April 1941 during the Second World War, she laid minefields along the Dalmatian coast, perhaps inadvertently leading to the sinking of two Yugoslav passenger ships. Slightly damaged by Italian dive bombers and then captured by the Italians during the invasion, she was soon handed over to the Germans. While in their service the ship was renamed Drache, had her anti-aircraft (AA) armament improved, and was used as a seaplane tender and later as a troop transport. In the latter role she participated in over a dozen convoys between the Greek port of Piraeus and the Greek island of Crete between December 1941 and March 1942.
The action off Lerwick was a naval engagement on 17 October 1917 fought in the North Sea during the First World War. The German light, minelaying cruisers SMS Brummer and Bremse attacked a westbound convoy of twelve colliers and other merchant ships and their escorts, part of the regular Scandinavian convoy. The two escorting destroyers and nine neutral Scandinavian ships were sunk off Shetland, Scotland.
Z16 Friedrich Eckoldt was a Type 1934A-class destroyer built for Nazi Germany's Kriegsmarine in the late 1930s. It was named after Kapitänleutnant Friedrich Eckoldt (1887–1916), the commander of torpedo boat V 48, who was killed when his boat was sunk during the Battle of Jutland on 31 May 1916.
HMS Southern Prince was a motor ship that was built in 1929 as the refrigerated cargo ship Southern Prince. She was commissioned into the Royal Navy in 1940 as a minelayer. She became a headquarters ship and then an accommodation ship in 1944, was a fleet training ship in 1945, and returned to civilian trade in 1946. In 1947 she was sold to Italian owners who had her refitted as a passenger ship and renamed her Anna C. From 1952 she was a cruise ship. She was scrapped in 1972.
HMS Teviot Bank was a Bank Line steamship that was built in England in 1938 as the cargo ship Teviotbank. In the Second World War she was a Royal Navy auxiliary minelayer. By 1956 a Panamanian company had bought her and renamed her Nella. She was scrapped in Italy in 1971.
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HMS Telemachus was a R-class destroyer of the British Royal Navy that took part in the First World War. She was built in 1916–1917 by the Scottish shipbuilder John Brown at their Clydebank shipyard. Telemachus was modified to serve as a minelayer, laying minefields in the German Bight and English Channel to restrict the operation of German submarines. The ship survived the war and was sold for scrap in 1927.
Iltis was the lead ship of her class of six torpedo boats built for the German Navy during the 1920s. The boat made multiple non-intervention patrols during the Spanish Civil War in the late 1930s. During World War II, she did not participate in the Norwegian Campaign of 1940 as she was under repair after having accidentally rammed and sunk a U-boat. Iltis spent the next couple of years escorting minelayers as they laid minefields and laying minefields herself. She also spent the latter half of 1941 escorting convoys through the Skaggerak. The boat returned to France in 1942 and was one of the escorts for the capital ships sailing from France to Germany through the English Channel in the Channel Dash. Iltis then helped to escort one commerce raider through the Channel and was sunk by British forces while escorting another blockade runner in May.
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The German torpedo boat T6 was one of a dozen Type 35 torpedo boats built for the Kriegsmarine during the late 1930s. Completed in 1940, she initially escorted ships through the Skaggerak before she was assigned to escort minelayers as they laid their minefields in the North Sea and English Channel in July. T6 started laying her own minefields two months later and was flagship of the 2nd Torpedo Boat Flotilla when she struck a mine and sank when attempting to attack several convoys off the Scottish coast in November.
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