A mine damages HMS Nelson

On the morning of 4 December 1939, at 7.52 a.m. or a few minutes later, the battleship HMS Nelson, flagship of the British Home Fleet, struck a magnetic mine in the entrance to Loch Ewe on the north-west coast of Scotland. The explosion beneath the forward part of the hull tore a hole about three metres by two in the plating, flooded several compartments and left the ship down by the bow. Nobody was killed, but according to British records 73 or 74 sailors were injured. Nelson reached the anchorage under her own power, but she was trapped in the loch for a month and reached a dockyard only in January 1940. She returned to service in the summer.

Some chronologies attribute the laying of the mine to the submarine U-52. In fact the minefield in the entrance to Loch Ewe had been laid five weeks earlier, on 27 October, by U-31 under Kapitänleutnant Johannes Habekost. What is correct is that the battleship was out of service for about six months.

A fleet without a safe base

Loch Ewe was a long, deep sea loch in the county of Ross and Cromarty, far from towns and railways. Before the war it had not been a fleet base. It became one out of necessity. After U-47 under Günther Prien had penetrated Scapa Flow on the night of 13–14 October 1939 and sunk the battleship Royal Oak, the Admiralty judged the main base in the Orkneys unsafe until its barriers and anti-aircraft defences had been completed. From then on the main body of the Home Fleet under Admiral Charles Forbes used substitute bases: Loch Ewe, the Clyde and Rosyth. None of them was well protected against submarines, and above all against mines.

The Germans knew this well. The commander of the U-boat arm, Karl Dönitz, sent U-boats to mine the approaches to the places where British warships might lie. From the first weeks of the war submarines had been secretly mining British waters with ground mines fitted with magnetic pistols, which exploded beneath a steel hull passing over them. U-31, an ocean-going Type VIIA boat which in September had been one of the first to attack a British convoy, laid a field of such mines on 27 October in the channel leading into Loch Ewe. The British did not detect it: their minesweepers swept moored mines, but they did not yet have effective sweeps for mines lying on the seabed.

It was a difficult time for the Home Fleet. On 30 October, west of the Orkneys, the German U-56 under Kapitänleutnant Wilhelm Zahn fired three torpedoes at Nelson. According to Zahn’s report at least two hit, but none exploded; it was one of the first signs of the German torpedo crisis. It is often written that Winston Churchill, First Lord of the Admiralty, and the First Sea Lord, Admiral Dudley Pound, were on board at the time. The records of the ship’s movements show, however, that both came aboard Nelson a day later, on 31 October, when the battleship returned from sea, and conferred there with Forbes about where the fleet should be based until Scapa Flow was safe. In November magnetic mines off the British coast sank 27 merchant ships and the destroyer Blanche, and severely damaged the cruiser Belfast in the Firth of Forth. At the beginning of December Nelson was returning to Loch Ewe after the pursuit of the German warships that had sunk the Rawalpindi.

The explosion in the entrance to the loch

On the morning of 4 December Nelson, escorted by the destroyers HMS Faulknor, Firedrake, Forester and Fury, was entering the loch. The battleship was commanded by Captain G. J. A. Miles and flew the flag of Admiral Forbes. The mine exploded under the starboard side, forward of A turret. According to the British damage report, the explosion tore a hole in the plating and dished the plates over a length of more than twenty metres. Seven compartments were flooded, including the torpedo compartment, and oil from the damaged double-bottom tanks leaked into the magazine of A turret. The ship took on a slight list and settled by the bow. The machinery was undamaged.

At first it was thought that the battleship had been torpedoed. The escorting destroyers, except Firedrake, stayed outside and hunted for a submarine that was not there. Nelson proceeded to the anchorage. Once it became clear that the cause was a mine, the problem turned out to be more serious than a torpedo would have been: nobody knew how many more mines lay in the channel. The damaged ship could not leave the loch until the entrance had been cleared. On 6 December Admiral Forbes struck his flag in the damaged ship and went ashore.

Minesweeping took almost a month. The British already understood how the German pistol worked, because on 23 November an intact mine had been defused at Shoeburyness in the Thames estuary, but magnetic sweeps were only just being developed. On 23 December two armed trawlers, Glen Albyn and Promotive, were sunk on the same minefield. Only once further mines had been swept could Nelson leave Loch Ewe, on 4 January 1940. Escorted by destroyers, she sailed to Portsmouth, arriving on 8 January.

Secrecy and repairs

The Admiralty did not make the damage public. After the sinking of Royal Oak and the damage to Belfast, the news that the flagship of the Home Fleet had been put out of action by a German mine would have been another blow to British prestige and valuable information for the enemy. For a month the battleship lay in a remote Scottish loch, out of sight of onlookers, and she sailed to Portsmouth like any other ship going in for a scheduled refit. Britain’s heavy ships were in any case dispersed: at the same time the battlecruiser Renown and the aircraft carrier Ark Royal were searching the South Atlantic for the German pocket battleship Admiral Graf Spee, which had been sinking ships there since the end of September.

At Portsmouth the ship entered dry dock in mid-January. While the hull was being repaired, part of her anti-aircraft armament was replaced and her first air-warning radar was fitted. According to the ship’s log, at the beginning of June 1940 she underwent degaussing trials, and on 6 June she sailed from Portsmouth for Greenock on the Clyde. Some accounts state that the repairs and modernisation lasted until August 1940. Either way, Nelson missed the entire Norwegian campaign, in which the Home Fleet badly needed heavy ships.

Significance

The mine in the entrance to Loch Ewe was the last great success of the German mining campaign of the autumn of 1939. It showed that the substitute fleet bases were just as vulnerable as Scapa Flow, and that a single submarine could put one of the most powerful battleships in the world out of the war for many months. The Admiralty accelerated work on magnetic sweeps and on degaussing hulls; in the winter of 1939–1940 warships and merchant ships began to be girdled with cables carrying an electric current, and the mine crisis slowly subsided. In March 1940, once the barriers and defences of Scapa Flow had been strengthened, the Home Fleet returned to the Orkneys. Loch Ewe later became an assembly point for the Arctic convoys to the Soviet Union.

U-31 did not survive for long. On 11 March 1940, during trials after a refit, she was sunk in the Schillig Roads near Wilhelmshaven by the bombs of a British Blenheim. She was the first U-boat of the war to be sunk by aircraft; her entire crew and the dockyard workers on board were killed. The boat was raised and repaired, but in November 1940 a British destroyer sank her for good.

Nelson served until the end of the war. In 1941 she covered convoys to Malta and in September of that year was torpedoed by an Italian aircraft; in 1942 she supported the Allied landings in North Africa; and on 29 September 1943, on board her at Valletta, Dwight Eisenhower and Marshal Pietro Badoglio signed the detailed terms of Italy’s surrender. In June 1944 she bombarded the coast of Normandy and struck a mine once again, and on 2 September 1945 the Japanese garrison of the island of Penang surrendered on board her at George Town. She was scrapped in 1949. The damage of December 1939 was one of many episodes in the Battle of the Atlantic, but it was a reminder that in its first winter Germany’s most dangerous weapon in the shallow waters around the British Isles was not the torpedo but the mine.