Luzon Mindanao Naval operations Convoy Hi-81 (ヒ-81) was the designation for a formation of Japanese transports that carried soldiers bound for Singapore and the Philippines during World War II.

Over the course of a four-day convoy battle in November 1944 nearly 7,000 Japanese were killed in action while the Americans sustained no casualties.

Shinyo was commanded by Captain Shizue Ishii and the Akitsu Maru was actually serving as an aircraft ferry in the convoy.

The other Japanese vessels known to have taken part in the mission was the seaplane tender Kiyokawa Maru, the destroyer Kashi, the escort ships Tsushima, Daito, Kume, Shonan, CD No.

[3] The torpedoes had hit aft and amidship on the port side, detonating the magazine and causing the vessel to keel over and sink in three minutes at position 33°17′N 32°00′E / 33.283°N 32.000°E / 33.283; 32.000.

In response Captain Ishii launched some of his twenty-seven depth charge-equipped Nakajima B5N torpedo bombers to search for the Queenfish but she got away.

The USS Barb, under Lieutenant Commander Eugene B. Fluckey, is credited with making an unsuccessful attack the same day on Junyo though she was not part of Convoy Hi-81 and was in company with three other ships, one a cruiser.

[4] After the sinking of Akitsu Maru, on November 16 Rear Admiral Tsutomu headed for Strange Island off the coast of Korea to shelter there for the day.

Spadefish fired four torpedoes; three of them hit the little chaser and it was completely destroyed after the initial explosion with all hands.

The Tsushima was also nearby and at 4:26 am her commander reported having sunk an enemy submarine with fifteen depth charges due to the sighting of an oil slick.

[7] Due to the sinking of four ships and the loss of thousands of men, Admiral Sato stopped the convoy in Raffle's Island anchorage near Shanghai to wait for his escorts to finish their rescue operations.