At the time of her requisitioning by Japanese Naval forces in 1941, 350 ft long Nippo Maru was a five hold Passenger-Cargo ship. After requisitioning she was converted to carry water containers. Her general mission was to supply water, ammunitions and supplies to forces in the area. She was sunk on Feb 17, 1942 and first discovered by J. Cousteau 1969 expedition to Truk.
Today, she sits on the bottom at about 165 ft with her deck raising to 110-115 ft in the bow area and 130 at the stern. She is almost upright and relatively intact. There are a lot of artifacts on her decks and her holds are full of items like mines, detonators, gas masks, AA gun ammunition, water storage tanks, etc.
Highlights are numerous and include battle tank on her deck; couple of trucks; AA gun behind the midship superstructure. There are only two ships that I know of that carry tanks on their top decks - Nippo and San Francisco Maru. Nippo's tank is easily recognizable as it does not have a turret. Anchor is still sitting in its place on the bow. Nippo has probably the most picturesque pilot house in the lagoon with telegraph and compass binnacle still standing
Hazard is really only one - depth.