Submarines in the Pacific War

statistics:

OWI Poster "Hit'em Where it Hurts! Join the Submarine Service", ca. 1943 (NARA photo NWDNS-44-PA-23)

• 200 U.S. subs sank 201 Japan warships and 1113 merchant ships
• total Japan loss of 4.7m tons, 55% total ships
• 211 subs built - 182 operational peak in 1945
• U.S. would lose 52 subs with 3503 crew
• Japan lost 112 subs; had 60 at start of war
• Germany lost 784 subs with 28,000 crew
  • 1162 German subs built
  • 240 operational peak
  • sank 5150 ships, 21m tons Allied shipping

evolution:

• The Pacific Submarine Force began 1914 in Hawaii with four F-class boats
• 1921-33 - built 9 enormous V-class subs such as the 381' Argonaut - largest diesel sub built in US
• 1933-41 - built 56 new fleet subs; FDR was sub booster
• new design better than old S-class
  • 1500 tons, 300' long, 10,000 mi. range at 20 knots
  • underwater 9 knots, up to 72 hours
  • 4 electric motors for underwater, 252 batteries
  • 4 diesel motors for surface
  • carried 24 torpedos (4 stern tubes, 6 bow)
  • Mark 10 contact torpedo, Mark 16 magnetic torpedo
  • 4 deck guns: one 5", one 40mm, two 20mm forward
  • crew of 70 - tours of 60 days
  • periscope depth of 63' and extended 12' out of water
  • not visible until in range at 1200 yds
• 1930 London Naval Treaty required subs to remove passengers and crew to safety
• at first painted black, then changed to gray
• original tactics: deep submerge, locate target with sonar ping, fire torpedo at 100' depth, but no ship ever sunk by this method

strategy:

U.S. Pacific submarine on war patrol. Pacific sunlight silvers the sea, July, 1945 (NARA photo NWDNS-80-G-335390)

• until 1943, subs used individually for hit-and-run missions and support of surface ships
• but 1943 began systematic patrols of key traffic patterns rather than stay on perimeter
• July 1943 began to penetrate 4 straits into Sea of Japan
• emphasis on "Luzon bottleneck" - Luzon strait where oil imported from Sumatra and Java
  • 80% oil came from U.S. before war; stockpiled 1 year supply
  • 1943 imported 1.5m bbls per month; 1944 imports cut to 300,000 bbls by Nov.

bases:

• before war, bases at Pearl Harbor and Cavite (in Manila Harbor, not Subic Bay)
• after Pearl harbor, at Freemantle (SW near Perth) under Charles Lockwood, also at Brisbane
• after Marshalls taken (Eniwetok Feb. '44), base at Majuro atoll
• after Marianas taken (Saipan, Guam June '44), base at Apra harbor at Guam
• after Carolines attacked (Pelilieu Sept. '44), base at Ulithi atoll beg. Nov '44

innovations:

Launching of USS Robalo, May 9, 1943, at Manitowoc Shipbuilding Co., Manitowoc, Wis. 5/9/1943 (Patch NA photo)

• new SJ radar (surface ships) replaced older SD radar (aircraft only)
• Japan navy lacked radar in 1941
• PPI (plan position indicator) showed all blips in radar range in correct geographic arrangement
• TBT (target bearing transmitter) - night binoculars on bridge on rotating base to calculate bearing
• new GM engines replaced old HOR engines (German) that had weak gear wheel teeth and made noise
• adopted wolf-pack techniques
• but main problem was torpedos - persistent difficulty with Mark 14 magnetic exploder
• Dudley Morton on the Wahoo used tactics to compensate
• "down-the-throat" shot of full salvo of 6 torpedoes at point-blank range

1944 - key year of greatest successes:

• new electric Mark 18 torpedo - no bubbles, but slower
• used in 75% of kills by July
• new acoustic Mark 27 with sonar was only 10' long
• 7000 yd range - must be silent to launch
• new 5" deck gun, fathometer without pings, periscope with built-in radar
• short range FM sonar against mines

Leyte Gulf - Oct. 1944:

• completed destruction of Japan navy
• U.S. subs allowed to blockade Japan home islands, Formosa strait
• voyage of the Tang earned Medal of Honor for survivor Dick Kane, who had served on the USS Wahoo in 1942-43

1942 Pacific - 1600 - 3700

1942 Atlantic - see Atlantic War

Sources:

• Weir, Gary E. Forged in War: the Naval-Industrial Complex and American Submarine Construction, 1940-1961. Washington: Naval Historical Center, 1993. 314 p.
• United States Naval and Shipbuilding Museum
• Naval Historical Center has the Dictionary of American Naval Fighting Ships
• U-boat Net from Gudmundur Helgason
• Full Fathom Five: The U.S. Submarine War Against Japan
• World War II "Silent-Service" from Subnet
• The U.S. Navy in the Pacific War 1941 - 1945 from Tim Lanzendoerfer
• Pacific submarine museums: USS Batfish in Oklahoma, USS Becuna in Philadelphia, USS Cavalla in Galveston, USS Cobia in Wisconsin, USS Cod in Cleveland, USS Croaker in Buffalo, USS Lionfish in Fall River MA, USS Pampanito in San Francisco, USS Silversides in Michigan, USS Torsk in Baltimore, USS Gunnel and USS Bowfin in Hawaii. See also the German U-505 in Chicago