I-351-class submarine

The I-351-class submarine(伊三百五十一型潜水艦,I-san-byaku-go-jū-ichi-gata sensuikan) was a class of tanker/transport submarines built for the Imperial Japanese Navy (IJN) during World War II. The IJN called this type of submarine Senho type submarine(潜補型潜水艦,Sen-Ho-gata sensuikan). The type name, was shortened to Hokyū Sensuikan(補給潜水艦,Submarine Tanker). The IJN designed these submarines to support flying boats in forward areas. By the time the first submarine was finished, this capability was no longer needed and she was converted into an oil tanker. That boat, I-351, was sunk on the return leg of her second voyage in 1945; the second boat was destroyed by an American air raid before she was completed. Four additional submarines were planned, but were cancelled before they were laid down.