January - December 1943, The Campaign Accelerates
Overview:
As the war continues, the Allies completed the first major offensive in the Pacific Theatre against the Imperial Japanese forces. The New Guinea Champaign carried on under the codename “Operation Watchtower” continued till February of 1943.
Having overseen the testing and modifying torpedoes, Admiral Charles Lockwood overhauled submarine underwater tactics as soon as he became Commander of U.S. submarines in the Pacific (ComSubPac) in February following the accidental death of previous commander. Up until then the US submariners were forced to engage the enemy with ordnance that proved to be at least 70 percent unreliable. Often, Japanese merchantmen would enter port with unexploded American torpedoes thrust into their hulls.
The US begun submarine warfare against the Japanese shipping vessels. The most damages to the Japanese merchant ships were made by submarines and by the end of the 1943 about 2/3 of all sunken ships (296/433) were attributed to submarine attacks.
During this year, the US and Canadian forces were able to complete Aleutian Islands campaign, to recover parts of Alaska that was occupied by the Japanese. Alaskan islands of Attu and Kiska were the only US land territories that was seized by the Japanese during the war and here the only land battle on American soil happened with the second most casualty on US forces after Iwo Jima. In March 1943, the US Navy started a blockade and was able to sink nine Japanese cargo vessels during the campaign.
Also, when the US Central Pacific Campaign started against Japan, The Battle of Tarawa in November 1943, took place on the heavily fortified, Japanese-held islands of the Gilbert Islands which intensified the attacks on vessels in the area.
As a major naval power, even after the Pearl Harbor attack, the US alone destroyed 379 vessels and of all the Japanese vessels that were sunk in 1943, 63% were Cargo ships (272).
Expanded legend:
- U.S. submarines maintained operations off the east coast of Japan, sank 39 vessels during consistent operations throughout 1943. 16 of these vessels were sunk off the coast of Tokyo and on shipping lanes connected to the Japanese shipping hub, Truk.
- The US submarines were able to destroy five vessels of South of Shikoku island and East of Okinawa island, 2 November 1943
- U.S subs sunk 13 merchant vessels during several raids surrounding the island of Palau between May to December 1943. Palau was a shipping node which connected the Philippines to Japan's garrisons in New Guinea, the Solomon Islands and New Britian.
- At the battle of the Bismarck Sea, the U.S. and Australian air forces sink seven Japanese vessels near New Guinea. 3 March 1943. As the Japanese lost these ships while trying to land more troops in New Guinea, this counts the most loses of ships on a single day in a year of 1943.
- Taking major loses, the Japanese started to withdraw from the Guadalcanal and went ahead with organized evacuations, they’ve lost four vessels, 20 January 1943.
- Between January and June, the Japanese Navy lost about 10 vessels in this area, and more than half of them were the victims of submarine attacks.
