April 4, 1944 when the air raid sirens sounded at Dublon Island, Truk the Japanese submarine I-169 was at anchor. The submarine was conducting a supply replenishment when the order was given to dive. The
commander, and 20 crew were on shore so it was another officer who gave the order.

With the main induction valve and several hatches open the I-169 sank like a rock. Those who were sill alive survived at least 24 hours while several rescue attempts were made but, by the end of the day April 5, no more sounds were heard from the interior of the boat.

During the salvage effort 32 bodies were recovered but some sources indicate there were over 100 on board when she sunk. The additional people were workmen involved with making repairs to the boat. In May the I-169 was rigged with depth charges and partially destroyed keep the boat from falling into US hands.