A relic from the second world war, the wreck of a Japanese submarine was found Thursday during a search for unexploded munitions on the seabed of a Papua New Guinea, according to the Australian Department of Defence. Australian and New Zealand warships found it resting half-buried 180 feet underwater during a search to clear WWII-era explosives  Rabaul Papua New Guinea was a major Japanese military base on the northeast coast of the South Pacific nation.

An examination of this photo, conducted by Australian Navy historians, concluded that the wreck is partially buried but upright. The next step is for the Royal Australian Navy to collaborate with Japanese authorities in determining the sub's identity. Gary Oakley, an Australian War Memorial curator and a former submariner, said it appeared to be a midget submarine crewed by one or two men. Three fleet submarines traveled with the attack fleet launching the attack on Pearl Harbor. They were placed in a line 100 miles ahead of the carriers. In Hawaiian waters,  the subs floated on the sea in the night, and in the daytime they descended to periscope depth. The mini-submarine's mission: to penetrated Pearl Harbor and each fire two torpedoes, while twenty others were stationed in Hawaiian waters.

According to www.ww2pacific.com/japsubs.html. Japanese Submarine I-16  was sunk on December 7th 1941. I-16 was never found. One account says she fired at the St Louis. Another account says she entered Pearl Harbor and was sunk after she managed to fire torpedoes at the West Virginia and Oklahoma. Other mini-subs that penetrated Pearl Harbor and were sunk, included I-22, which was sunk by the Monashian. I-18, which was sunk by the Ward outside the harbor. I-20, which was sunk outside the harbor after a mechanical failure. And then there was the I-24, which ran agound outside Pearl Harbor 

Oakley says japanese midget submarines were transported by ship or larger submarines and used covertly to infiltrate enemy targets  Such a submarine could have been destroyed by an American air attack or  naval bombardment or even scuttled by the Japanese themselves toward the end of the war