Marco Polo was a cargo ship built under a
US Maritime Commission contract (as MC hull 1356), by the
North Carolina Shipbuilding Co.,
Wilmington, North Carolina. The ship was renamed
Mount Hood on 10 November 1943; launched on 28 November 1943; sponsored by Mrs. A. J. Reynolds; acquired by the Navy on loan-charter basis on 28 January 1944; converted by the
Norfolk Shipbuilding & Dry Dock Co.,
Norfolk, Virginia, and the
Norfolk Navy Yard; and commissioned on 1 July 1944. Following an abbreviated fitting out and shakedown period in the
Chesapeake Bay area, ammunition ship
Mount Hood reported for duty to ComServFor, Atlantic Fleet, on 5 August 1944. Assigned to carry cargo to the Pacific, she put into Norfolk, where her holds were loaded. On 21 August, as a unit of Task Group 29.6, she transited the
Panama Canal on the 27th, and continued on, independently, via
Finschafen,
New Guinea.
Mount Hood arrived at
Seeadler Harbor, in
Manus Island of the
Admiralty Islands, on 22 September. Assigned to
ComSoWesPac, she commenced dispensing ammunition and explosives to ships preparing for the Philippine offensive.
Disaster On 10 November, the ship was lying in Berth 380, in the central part of the harbor near the harbor entrance, instead of being moored well away from the main anchorage. This was done for reasons of convenience, as it afforded her calmer water, shortened the boating distances for ammunition transfer, and allowed cruisers to come directly alongside her for munitioning. She was loaded with an assortment of munitions, including bombs, shells and powder charges, .30 cal., .50 cal machine-gun and 20 mm cannon cartridges, aerial depth charges, and rocket projectiles and motors for a total of approximately 3,800 tons of ammunition. The ship was surrounded by small craft, including several medium-sized LCM landing craft. All five of her hatches were open, and 500 lb bombs were being loaded into #3 Hold. At 08:30 on 10 November 1944, a party consisting of communications officer, Lt. Lester H. Wallace, and 17 men left the ship and headed for shore to collect the ship's mail. At 08:55, while this party was walking on the beach, the ship exploded. Even at a distance of from the ship, the force of the explosion knocked Wallace and most of his men from their feet. Scrambling back into their boat, they headed back to the ship, only to turn around again shortly thereafter as "There was nothing but debris all around...".
Mount Hood had been anchored in about of water. The initial explosion caused flame and smoke to shoot up from amidships to more than masthead height. Within seconds, the bulk of her cargo detonated with a more intense explosion. Mushrooming smoke rose to , obscuring the ship and the surrounding area for a radius of approximately .
Mount Hoods former position was revealed by a trench in the ocean floor long, wide, and deep. The largest remaining piece of the hull was found in the trench and measured no bigger than . No other remains of
Mount Hood were found except fragments of metal which had struck other ships in the harbor and a few tattered pages of a signal notebook found floating in the water several hundred yards away. No human remains were recovered of the 350 men aboard
Mount Hood or small boats loading alongside at the time of the explosion. The only survivors from the
Mount Hood crew were Lt. Wallace and the 17 enlisted men who had left the ship a short time before the explosion. Two of the crew were being transferred to the base brig for trial by court martial, and the remainder of the party were visiting the base chaplain or picking up mail at the base post office. Charges against the prisoners were dropped following the explosion. The concussion and metal fragments hurled from the ship caused casualties and damage to other ships and small craft within . The repair ship , which was broadside-on to the blast, was the most seriously damaged. All personnel topside on
Mindanao were killed outright (including a crewman from
Mount Hood who had been working on
Mindanao at the time of the explosion—he was the only one of
Mount Hood's deceased crew members who was positively identified). Dozens more men were killed or wounded below decks as numerous heavy fragments from
Mount Hood penetrated the side plating. Eighty-two of
Mindanaos crew died. After only a little over four months' service,
Mount Hood was struck from the Naval Register on 11 December 1944. ==List of ships damaged==