Boston Deep Wrecks - USS YF-415

The YF415 was a US Navy freight lighter built by the American Ship Building Company in their Buffalo yard. Commissioned in October of 1943, it was 130 ft. long with a 30 ft. beam. Designed for hauling freight in harbors and coastal waters, it had twin 300 BHP diesel engines, a large winch with freight boom, towing bitt and space for 10 crew. Chief Boatswain’s Mate Louis Tremblay took command of the vessel in Buffalo and brought her to the Boston Navy Yard for service.

On May 10, 1944 the YF415 received orders from the Captain of the Yards office, Boston, to proceed to the Naval Ammunition Depot in Hingham to pick up a quantity of obsolete munitions for disposal, which at that time called for dumping overboard in deep water. At 8:30 am on the morning of May 11, the 415 left Hingham harbor with approximately 150 – 200 tons of munitions primarily consisting of pyrotechnics (Mark II signal rockets), black powder and 5 inch projectiles. In addition to the 9 crew members on the boat, a contingent of 21 officers and men from the Naval Barracks in Hingham was on board to help with the disposal. All of the ordnance was carried on the deck – in the large weather deck (compartment), and on bow and stern. At approximately 12:25pm, after having unloaded about two thirds of the munitions, some of the pyrotechnics ignited in the weather deck just beneath the bridge and touched off a maelstrom of explosions and intense fire. Men scrambled for their lives, and most leaped overboard without time to grab life jackets or launch the lifeboat. The fire and explosions continued for 20 – 30 minutes before finally sinking the ship. The USS Zircon, under the command of Lt. Bird, witnessed the initial explosions and proceeded towards the YF – 415 immediately. However, burning debris from the explosions kept the rescue boats from getting close enough to pick up survivors for almost 35 minutes. The fire itself and cold waters claimed 17 men, including six of the nine crewmen. Thick fog in the area hampered the rescue operation and also severely limited the estimate of the position of the sinking, and the exact position of the wreck was never determined.

The wreck of the YF – 415 was located in late October 2002 by me (Bob Foster), working with Captains Heather Knowles and Dave Caldwell of Northern Atlantic Dive Expeditions, in 240 FSW about 16 miles ENE of Boston. It was actually marked long before (as are most wrecks) by fishermen in the area who set their nets nearby. Due to the water temperatures at the time, the wreck was not dived until July of 2003. Joined by Jack Ahern and Donna Chaston, we surveyed and finally positively identified the wreck based on a US Navy stamp found on a compass fragment along with general ship dimensions and features. Damage found on the ship also closely matched the descriptions later found in statements provided in naval documents from a large de-classified file in the National Archives.

Today the YF – 415 sits upright with the bow buried firmly in the muddy bottom and the stern and props fully exposed. The bridge and other structures mounted on top of the weather deck have been torn away over the years by nets, leaving the weather deck the only remaining covered structure on the deck. The roof of this large room, which spans the entire width of the ship, has been burned through in several areas. A large pile of debris rests at the forward end of the compartment. The ship’s funnel lies beside the wreck along the starboard side. Penetration is possible into all interior areas including the engine room, forward cargo area, and crew’s quarters / galley in the bow, which is accessible through a snorkel-like hatchway protruding from the mud. Entering the galley/crew quarters means actually going below the mud bottom. All these areas are filled to a large extent with a thick layer of mud and silt - at least two to three feet in most areas, making penetration a bit tricky. Visibility is usually good on this wreck, and it is easy to navigate. However the depth, cold temperatures and limited ambient light make this a very advanced dive.

I was sitting in the galley eating. We left Hingham at 0830 with some flat-nosed projectiles, 3 inch common, and 3 inch AA, and miscellaneous pyrotechnics and black powder. Total tonnage about 200 tons. Flat nosed projectiles were 5, 3, and 4 inch. At 1130 we arrived at the dumping ground and proceeded to throw overboard, first the black powder and then the projectiles. By about 1245 the load was approximately two-thirds off and three officers remained on the topside supervising the unloading, while 3 others went below to chow. On the topside were Lt. Doering, Lt. Knox, and CBM Tremblay. Gunner Hormak and Ensign Bowen and myself had just finished eating when the first explosion occurred which drove small pellets from the pyrotechnics through the galley door. This occurred about 1 o’clock. It was impossible to get out of the forward compartment for a few minutes and at the first lull, we all left the compartment and ran for the fire hose which is right outside of the compartment but the explosions and flames from the pyrotechnics was so great that it was impossible to face it. I told everybody to get up forward and hang over the side. At the time we did this the whole forward deck appeared to be a mass of flame and explosions. I saw Tremblay on the bridge and he was trying to get some men off the stern. Three of us stayed hanging over the bow until about five minutes before the ship went down as I would now allow anyone to drop into the water because of the danger of the missiles. I would say that we stayed there about one hour.

My idea of what caused the explosion is that the matches that are in with the rockets, six in each rocket, must have ignited some how. The pyrotechnics which went off first were stored in the compartment underneath the bridge, but doors on both ends were opened because we had been removing projectiles from the same compartment first. There were some projectiles and pyrotechnics on the well-deck forward, but they didn’t go off first. I heard no heavy explosions from the compartment under the bridge, which leads me to believe all the projectiles had been removed from there, and that the fire started among the pyrotechnics, on which some men were working at the time. I believe that all of the projectiles on the stern had been disposed of as I heard no explosions on the stern during the entire affair.

A page from the very large file found in the National Archives on the sinking. As a result of the investigation, never again would ordinance be disposed of from a powered vessel.

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