Japanese ww2 submarines

Everyone who studies WW2 knows that Allied & German subbies played a major role in that war, but not everyone knows much about Japan's subby fleet then.

Japan got her first subs from the Holland Co. in 1904, but didn't use them in the Russo-Japan war. japan made progress in both quality & quantity as time passed, She used them some in WW1.

By WW2, Japan had one of the largest & most-varied sub fleets on earth, able to perform a wide range of missions, from fighting to troop/supply transport. While their combat subs couldn't dive as deep nor were as fast as US subs of the Tautog class, they had the HUGE advantage of the famed "Long Lance" torpedo, which ran straight & true at speeds up to 60 MPH, with a running range of over 20 miles. This torpedo, used in both subs & surface ships, was the best in the world for most of the war, remaining formidable thruout the war. (It made Japanese destroyers every bit as dangerous as their battleships !)

While US subs largely concentrated on enemy merchant ships, the subs' natural prey, the Japanese concentrated on trying to sink enemy warships, mostly in fleet actions,which wasn't often easy. Even so, Japanese subs managed to sink some million tons of enemy merchant shipping. But their record against warships was spotty. Twice, subs torpedoed & disabled the carrier Saratoga, putting her out of action for months at a time. After the Battle of Midway, I-168 sank the disabled carrier Yorktown & the destroyer Hamman with one torpedo spread. The I-19 sank the carrier Wasp & damaged the battleship North Carolina & the destroyer O'Brien, all with one torpedo salvo, in on Sept. 15, 1942. On Nov. 23, the I-175 sank the escort carrier Liscome Bay, with heavy loss of life..And on July 30, 1945, the heavy cruiser Indianapolis was sunk by I-58 with heavy loss of life. (My uncle had gotten off her at Tinian shortly before, along with the uranium for the A-bomb used on Hiroshima.) Otherwise, the subs' success was mostly against destroyers, minesweepers & minelayers, & other lesser USN ships.

The Japanese sub crews were superbly trained, & their officers were considered the best of the best. However, it was the TACTICS OF THE SUB FLEET'S TOP COMMANDERS that greatly limited the IJN subs' effectiveness & doomed many of them. The aforementioned tactic of fleet action with surface ships placed many subs in harm's way. And the many supply/troop transport runs kept many of them from hunting the enemy. The giant 400-ft. long !-400 class subs were built with the intent of their launching & recovering aircraft in unexpected places, also carrying torpedoes for ordinaru subby combat, but were quickly relegated to the role of supply ships as the war turned against Japan & she couldn't supply isolated island garrisons by surface ship due to Allied air power.

But the worst tactic of all was the PICKET LINE, where the subs lined up in a row, several miles apart. All the Allies had to do was find out the alignment of a particular line & roll it up. The USS England, a destroyer escort, (named after Ensign John England, killed at Pearl Harbor)was among several anti-sub ships alerted for a 7-boat picket line forming off the Admiralty Islands along a route Adm. Halsey had taken the 3rd Fleet down before. The England, along with her squadmates Raby& George, was equipped with the British "Hedgehog" anti-sub weapon that fired 24 contact-fused shells about 250 yards in front of the attacking ship in an arc. It had a 30-lb. Torpex warhead which could hole a sub. Using this weapon, England found the end boat of the picket by sonar line & sank it. She then discovered the picket alignment & followed it, sinking 6 subs in 12 days. (She failed to find one of the 7 subs.)

Despite the obvious failure of the picket line tactic, the IJN stuck with it, along with the policy of keeping the subs near routes Allied warships used, rather than the routes used by merchantmen. The Japanese sub fleet coulda made things a lot tougher for the Allies had they focused on the merchant traffic, including the west coast of the US & the Panams Canal zone.