The American submarine war in early 1944

On 27 February 1944 the American submarine USS Cod torpedoed and sank, west of Halmahera in the waters of the Moluccas, the 2,473-ton Japanese cargo ship Taisoku Maru, which was serving the army. This is how the event is recorded in the official US Navy chronology and in the post-war list of Japanese shipping losses compiled by the American JANAC committee. In itself it was a minor episode: a small ship, sunk without fanfare, one of several dozen sinkings that month. That is precisely why it illustrates so well what the American submarine war had become by early 1944. After two troubled years it had turned into the daily, systematic destruction of Japanese shipping, on which both the industry of the home islands and the garrisons scattered across the whole Pacific depended.

The submarine and her captain

Cod was a Gato-class submarine, built by the Electric Boat Company at Groton. She was launched on 21 March 1943 and commissioned on 21 June. She was commanded by Lieutenant Commander James C. Dempsey, one of the few officers who already had a major success to his name: in February 1942, in the old boat S-37, he had sunk the destroyer Natsushio in the Makassar Strait – the first Japanese destroyer sunk by an American submarine.

Her first patrol, from Brisbane to the South China Sea in the autumn of 1943, produced no sinkings. After a refit at Fremantle in Western Australia, home of the submarine base of the South West Pacific forces, Cod set out on her second patrol on 11 January 1944. She operated in the South China Sea, off the coast of Java and in the area of Halmahera. On 16 February she sank a Japanese sampan by gunfire. On 23 February, off Halmahera, she torpedoed the fleet tanker Ogura Maru No. 3 (about 7,400 tons), which according to JANAC went to the bottom. Four days later it was the turn of Taisoku Maru. Two days after that Cod attacked another ship, but the escort forced her to dive deep and depth-charged her. On 13 March she returned to Fremantle.

One point about the event of 27 February therefore needs clarifying: the vessel sunk was a merchant ship, but one serving the army as a cargo transport. American sources give no precise details of her cargo or of the number of casualties among her crew.

Torpedoes that finally worked

For almost two years American submariners had been let down by their main weapon. The standard Mark 14 torpedo ran deeper than it was set, its magnetic exploder detonated prematurely or not at all, and its contact exploder failed when the torpedo struck at a right angle. Each of these defects was discovered at the front, often in the face of opposition from the Bureau of Ordnance. On 24 June 1943, at the request of Rear Admiral Charles Lockwood, commander of the Pacific Fleet’s submarines, Admiral Chester Nimitz ordered the magnetic exploders deactivated, and in September 1943 torpedoes with improved contact exploders reached the boats. In Australia it took longer: Rear Admiral Ralph Christie, commander of the Fremantle submarines and one of the developers of the magnetic exploder, defended it until the turn of 1943 and 1944, when the new commander of naval forces in the South West Pacific, Vice Admiral Thomas Kinkaid, ordered it switched off. Cod set out on her second patrol under the new conditions. To this was added the electric Mark 18 torpedo, which left no trail of bubbles on the surface.

The second pillar of the breakthrough was intelligence. From the beginning of 1943 the Americans were reading the code in which the Japanese navy directed merchant shipping, and reports of convoys’ departures, their courses and their noon positions often reached the submarine staffs faster than they reached the escorts themselves. The boats no longer had to search for targets blindly. There were also more and more submarines: new Gato- and Balao-class boats were coming out of American yards, and overcautious captains were being replaced by younger and more aggressive ones.

Wolf packs and the hunt for tankers

From October 1943 the US Navy sent submarines out in small groups for coordinated attacks – on the model of the German wolf packs, though usually made up of three boats. Japan responded in November 1943 by creating the Grand Escort Command, which was to organise a convoy system for the first time. But there was a shortage of escort vessels, patrol aircraft and experience: for two years the Japanese navy had treated the protection of shipping as secondary to fleet battles.

In 1944 the Americans made tankers, which carried oil from Borneo and Sumatra to Japan, their chief target. On 19 February USS Jack attacked a convoy of six tankers in the South China Sea, about 300 miles west of Luzon, and sank four of them. According to the JANAC list, American submarines sank about 20 Japanese tankers in the whole of 1943, and about 70 in 1944. For a country that had gone to war to win the oil of the Dutch East Indies, this meant that the oil was within reach but ever harder to bring home.

February 1944

February 1944 was one of the best months of the whole war for American submarines. According to the JANAC list, they sank some 55 vessels in that time with a combined tonnage of more than 260,000 tons, markedly more than in January. They operated on every route: from the Kuril Islands and the East China Sea, through the South China Sea, to the waters of the Dutch East Indies. They also supported the offensive in the Central Pacific. On 16 February USS Skate sank the light cruiser Agano, which was escaping from the base, north of Truk, and a day later Admiral Marc Mitscher’s carriers began Operation Hailstone, destroying dozens of ships in the Truk lagoon. The new boat USS Tang, under Lieutenant Commander Richard O’Kane, sank five ships from convoys bound for Truk and the Marianas in the second half of February, on her first patrol.

The submarine war also had victims whom neither side intended. The Japanese carried prisoners of war and forced labourers from the occupied countries by ship, and through a periscope they could not be told apart from soldiers. On 25 February USS Rasher sank the ships Ryūsei Maru and Tango Maru north of Bali. Aboard the latter, besides Japanese soldiers, were about 3,500 Javanese forced labourers (rōmusha) and Allied prisoners of war, most of them probably soldiers of the Dutch East Indies army. According to available estimates, at least 3,000 people died.

The Americans paid a price too. At the end of February USS Grayback, one of the most successful boats of the war, was lost in the East China Sea, most likely sunk by Japanese aircraft, and on 29 February, while attacking a convoy bound for Guam, USS Trout was lost, most probably sunk by the destroyer Asashimo. Both boats went down with all hands. Risk was part and parcel of the service – only three months earlier, in November 1943, USS Corvina had gone to the bottom near Truk, the only American submarine sunk by an enemy submarine.

Place in the war

The rest of 1944 confirmed what February had foreshadowed. According to tallies based on JANAC data, American submarines sank about 600 Japanese vessels in the whole of 1944, twice as many as the year before. In June, in the Battle of the Philippine Sea, they sank two large carriers, Shōkaku and Taihō, and in the autumn they struck at convoys bound for the Philippines. By early 1945 the Japanese merchant fleet had practically ceased to exist as a whole: Japan, unable to keep pace in building new ships, was losing far more of them than it could replace, and its war industry was choking for lack of oil, bauxite and ore. In its post-war summary JANAC credited American submarines with sinking about 4.8 million tons of Japanese merchant shipping and more than half a million tons of warships – more than half of all Japanese losses at sea. The price was high: the US Navy lost 52 submarines in the war, all but one of them in the Pacific.

Cod survived the war. On 10 May 1944, attacking a large convoy off the west coast of Luzon, she sank the old destroyer Karukaya and a transport, and in July 1945 in the Gulf of Siam she rescued the crew of the Dutch submarine O-19, which had run aground on a reef – this is regarded as the only case in history of a submarine of one country evacuating the crew of another country’s submarine. For seven war patrols she received seven battle stars. Since 1959 she has been berthed at Cleveland on Lake Erie, and since 1976 she has been a museum ship, designated a National Historic Landmark of the United States. She is the only surviving American Second World War submarine that visitors enter by the same vertical ladders as her wartime crew. Her 27 February 1944, an ordinary working day for a submarine, was one of thousands of similar days that together added up to the destruction of Japanese shipping.