Four submarine campaigns of World War II


The British
The British submarine campaign was principally in the Mediterranean, where they sank many ships supplying Rommel's Afrika Corps. For a short while they were so successful they stopped supplies by sea and the Nazis had to supply Rommel with critical supplies by air. Late in World War II they and some Dutch submarines joined in the Pacific War, but because they were not air conditioned, many crewmen became ill with skin and other problems due to the tropical heat. They did some effective work in the Pacific. Some British mini submarines slipped into Norwegian Fjords and Japanese anchorages to damage German and Japanese warships and most escaped. Other mini subs helped point D-day landing barges to their beaches.

The Germans
German U-boats under Admiral Doenitz attacked merchant ships to cut off Britain from all supplies. For some months they were wildly successful, while other months improved allied counter measures reduced the menace. Late in the Battle of the Atlantic our anti-submarine weapons became increasingly successful and fewer U-boats returned from patrols. Special tactics in slowing the U-boats were:

  • Doenitz directed his U-boats from shore, and they radioed him. Those radio messages let our navies locate them; later the British broke the Enigma code so we read orders to U-boats;
  • a large area at the center of the Atlantic could not be covered by aircraft and U-boats sank many, so the U.S. built some 76 "jeep carriers" from tanker and freighter hulls, so Navy fighters and bombers could patrol the air for the entire Atlantic crossing to spot and attack U-boats; some jeep carriers went to the Pacific to provide air cover for beachheads;
  • the British developed "hedgehog" was smaller than depth charges, one or more were shot off the sides of escorts, sank faster than depth charges, and exploded only on contact;
  • the mass production of destroyer escorts, frigates, freighters and tankers by American shipyards and recruiting crews to man them despite dangers from U-boats and the cold north Atlantic. Rescue trawlers attached to convoys rescued survivors of sinkings.

As a result the allies were able to keep supplies moving across the Atlantic and by special protection and care get all but one American troopship safely across.

The Japanese
Japanese submariners felt it was honorable only to attack warships. Before the end of the Battle for Guadalcanal they sank or damaged a number of American carriers, battleships, and cruisers. German Admiral Doenitz urged Japanese leaders to attack merchant shipping, which they did briefly in the Indian Ocean. They failed to organize a campaign against the "sea train" that supplied American forces across the Pacific. After the Japanese loss of Guadalcanal in early 1943 increasingly submarines were diverted from offensive patrols to supply Japanese troops isolated by our island leap-frogging campaigns. In preparation for a couple of battles they were ordered into offensive action, but by then our code breakers were able to pinpoint most, and direct U. S. Navy hunter-killer groups, using skills mastered against U-boats in the Atlantic, to sink many Japanese submarines.

The American
The U. S. submarine offensive, after serious failures and delays, succeeded in isolating Japan from imports while at the same time sinking many warships. Attacks on merchantmen were frequently postponed until dark when radar enabled surface attacks with submarines' high speed and maneuverability. In early 1942 Japan had 6 million tons of "marus"; at the end of the war 231 Japanese sea going merchant ships remained afloat. The last several months of war 9% of oil shipped reached Japan. Unlike the allies in the Battle of the Atlantic, Japan was slow to build new "marus" and cheap escort ships to protect them, and their navy was slow to organize an escort system. Tokyo radioed all ships where they should be at noon each day in a code broken by FRUPac. The "honorable" thing was to build warships and planes to attack the enemy navy. For example, much steel and years of manpower were used to build the super carrier Shinano, converted from a sister of the battleship Yamato. Shinano was rushed, without completed water tight integrity, to the Inland Sea for safety from U.S. bombers. Several hours into that trip she was sunk by U.S.S. Archer-fish at night using radar.

A detailed comparison of the German and American submarine campaigns and their effects says that "the American Navy won a spectacular victory."

Copyright © 2006, 2010 John F. Yeaman