...off the coast of Hawaii:

The wreckage of a large World War II-era Japanese submarine has been found by researchers in waters off Hawaii (search).

A research team from the University of Hawaii (search) discovered the I-401 submarine Thursday during test dives off Oahu.

The I-400 Sensuikan Toku class sub appears to be in very good condition. This discovery introduced me to a minor but most interesting chapter in WW2 naval history.

It seems that this particular class of sub was the largest built prior to the '60s. An amazing 400 feet long and nearly 40 feet high, they carried a crew of 144 plus three birds. No joke. The sub included a waterproof, 3.5 m (11 ft 6 in) diameter, cylinder-shaped hangar which could hold three fold-up bombers (M6A1 Seirans).

The original mission the planes were designed for was to drop vermin infected with plague and other diseases on the U.S. mainland. Difficulties in preparing these early biological weapons caused the mission to be changed. The new mission involved bombing the Panama Canal. However, the subs were commissioned too late in the war to make any difference. When the war ended, the planes were scuttled and the subs surrendered to the U.S. Navy.

Other notable links regarding this little history lesson include this narrative by a sailor who boarded an I-400 Class Sub that surrendered off Sasebo, and this unique painting depicting 'The Final Act' of defiance by the Japanese - the scuttling of the Seirans from an I-400. Here is a model which gives an idea how the sub looked but does little to demonstrate the scale of this ambitious project. (These subs were 60% larger and had twice the range of the largest contemporary American submarine, the USS Argonaut.)

I love history.