The 'Poseidon' was a tanker in service with the Dutch East Indies Tank Steamship Company and was commissioned in 1914. In 1918 (WW I), the ship was seized by the American government pursuant to the Droit d'Angarie and placed under the USA flag. After the First World War, the Poseidon was returned to the NITSM.

WW II; Poseidon becomes Hosei Maru
On March 6, 1942, the Poseidon was in the port of Tjilatjap (Cilacap, Java). During the Japanese invasion, she was set on fire by her own crew and sank. The ship was salvaged and repaired by the Japanese on August 8, 1943. She subsequently sailed under the Japanese flag as the 'Hosei Maru'.

Sinking
On April 10, 1945, she was attacked by the Dutch submarine Hr. Ms. O-19 sunk by gunfire in the Java Sea at 05º-25' S and 106º-39' E.

At 12:22, O-19 fires two bow torpedoes at the port side of the 'Hosei Maru' from a distance of only 450 meters, but both torpedoes pass under the target without exploding.

The lookouts on 'Hosei Maru' see the torpedoes pass under the ship. The ship turns desperately to port to prepare for another torpedo attack, but at 12:25, O-19 surfaces behind 'Hosei Maru' and prepares for gun action.

The Japanese respond with small arms. The machine guns of the O-19 immediately suppress the resistance. At a distance of only 250 to 300 meters, the O-19 86 fires 8.8 cm shells into the tanker before her onboard gun jams.

Due to the short range, almost every shot hits its target and sets the ship on fire. Captain Muranaka Ribee orders “Abandon ship.” Because the only lifeboat was destroyed by shellfire, the men jump into the water. About 25 survivors cling to a capsized lifeboat and to anything else that floats.

At about 1:00 PM, the 'Hosei Maru' sinks bow first. Around 2:30 PM, the survivors are spotted by a seaplane requesting help via radio.

In the evening, the 'Kairyu Maru' arrives and picks up 38 survivors, including all 9 crew members, but 10 passengers are missing.

• tracesofwar.nl
• marhisdata id 5243
• combinedfleet.com/Hosei_t.htm
  Hosei Maru (ex-Poseidon)