The USS YF- 415 Project

The USS YF-415 was first identified by Bob Foster as an unknown, unique obstruction rising off the bottom on the November 3, 2002 and subsequently visited by a group of local divers who returned to dive the site on July 20, 2003. This group, which would form the principal exploration team, consisted of divers Jack Ahern, David Caldwell, Donna Chaston, Bob Foster and Heather Knowles.

The first two exploration dives, conducted on July 20 and July 27, 2003 yielded critical information that provided the basis for both further research and a theory as to the wreck’s identity. These dives revealed the wreck to be a United States Navy vessel. At that time, the team began treating the site as a war grave while continued efforts to document the wreck intensified.

Once the wreck was identified as a United States Naval vessel, the list of possible matches narrowed to one: the USS YF-415, sunk off Boston, MA on May 11, 1944.

History:

The USS YF-415 was built by the American Shipbuilding Company of Buffalo, NY and completed in September of 1943. Though it had been fitted with mine tracks for potential other uses, they had been removed, and the ship functioned primarily as a work lighter. The abbreviation “YF” is a ship classification that stands for “yard freight”. Twin 300 hp Union diesel engines powered the 132’ long vessel, which was designed to carry a cargo of 250 tons, stowed on deck. Operating exclusively in the Boston area, the vessel was manned by a mostly local crew of men based out of the Boston Navy Yard.

On May 10, 1944 the YF-415 departed for the Naval Ammunition Depot in Hingham, MA under the command of Chief Boatswain’s Mate Louis B. Tremblay of Marblehead, MA. The ship’s orders were to proceed to Hingham and load ammunition that would be disposed of in deep water off Boston. The YF-415 planned to take on additional crew at Hingham to assist in the disposal of the ordnance. Previously, the ship had made two such excursions to dispose ordnance and these had been uneventful.

The ship was loaded with approximately 150 tons of ammunition, which included obsolete pyrotechnics, black powder, and 50-caliber projectiles ranging from 3 – 5” in shell size, among other miscellaneous ordnance. The YF-415 was loaded to its maximum draft, though some claimed the ship was further weighted down to its gunwales. There was no official protocol, other than a pre-departure briefing from an officer with regard to procedures for the safe handling of the ammunition.

The YF-415 departed Hingham with five officers, ten men comprising regular crew and an additional work crew of sixteen African-American men from the Hingham ammunition depot for a total of thirty-one men. While underway, the crew prepared the ordnance for disposal, which involved sequestering projectiles from other explosives in anticipation of disposing of the most dangerous material first. At approximately 11:30 am on May 11, the YF-415 arrived in the disposal area where the crew proceeded to dump nearly two-thirds of the cargo, including much of the black powder and projectiles, uneventfully.

The rockets intended for disposal were normally buoyant and required special preparation to sink them, which called for the containers to be punctured following the removal of the package of matches. These measures would ensure that there was no chance of accidental ignition and that the containers sank as intended. However, the men were instead instructed to jam projectile shells into the rocket containers to make them sink and crush the containers to keep the projectiles from falling out. Despite orders from the Bureau of Ordnance to only punch holes in the buoyant containers to ensure sinking, this procedure was not followed. Chief Gunner Lee T. Ridenour, in charge of the disposal operation, later testified to the following procedure carried out while en route to the disposal area:

At no time did any officer, whether at the Hingham Ammunition Depot, or on board the YF-415, inspect the rocket containers to ensure the matches had been removed.

At approximately 11:30, the crew began dumping the ordnance. The relatively inexperienced enlisted African-American men from Hingham were charged with disposing the rockets. The disposal process proceeded as planned and without incident. However, according to Chief Boatswain’s Mate Tremblay, who was observing the disposal operation, he later testified that at about 12:30 pm he heard a “terrific whoosh” – a fire from an explosion of rockets, which set off a chain reaction of explosions, quickly engulfing the port side of the ship, spreading from amidships to the entire main deck.

The fire aboard the YF-415 raged uncontrollably and attempts to man fire fighting equipment were unsuccessful. Many were temporarily trapped in the crews quarters, located in the forward part of the ship, as intense flames and heat seared the lighter. One crewman, William J. Bradley, though he managed to escape from the engine room, suffered third degree burns over 76% of his body and later died. Most men drowned in the water, awaiting rescue. One sailor, Seaman second-class Yeo Jin was reported to have jumped into a shower during the panic in an attempt to shield himself from the fire on deck. He would not leave the crews quarters despite the efforts of his fellow sailors. They were eventually forced to leave to save themselves. They did not see Jin alive again. At no time did the abandon ship or emergency signal sound, as men began to flee the vessel on their own accord. With little time to don life preservers and rafts, many men simply went into the water, which was 50 degrees Fahrenheit, clinging to debris while waiting up to 45 minutes before they were rescued.

Numerous ships and vessels operating in the area were dispatched to conduct search and rescue operations. The USS Zircon, a nearby weather-observing vessel, ultimately rescued fourteen survivors, four crewmembers of which one later died from severe burns and ten men from the Hingham contingent. The missing sixteen men’s bodies were never recovered.

The Inquiry following the sinking made several recommendations, both with respect to proper protocol and safety measures for disposing ordnance as well as the use of vessels more appropriate for such hazardous activities. In summary, the report recommended that there be made available and posted in visible places standard instructions for draft, trim and deck loading as well as life preserver locations and safety precautions for the handling of dangerous cargo. In addition, it was recognized that a more appropriate vessel should have been used such as a non-self propelled lighter (barge) towed by a tug that could be easily abandoned should an accident occur.

Dive Exploration:

Several exploration dives of the site did not produce a positive identification, though considerable supporting circumstantial evidence was collected through observation and video survey. A detailed study of the wreck’s features, comparing them to archival photographs, provides support to the theory that this wreck is the USS YF-415. The wreck sits upright, bow-down in approximately 240 feet of water. The stern points upward with enough clearance to swim underneath the twin propellers. Though the wheelhouse is missing, it is believed to be in the vicinity of the wreckage, as it was likely carried away by fishing gear. The highest point of the wreck, an area where the wheelhouse once existed, can be reached in about 210 feet of water.

Divers have observed damage consistent with multiple explosions in the foredeck and deckhouse areas. Small shells and 50 caliber rounds have been observed in these areas as well, which fits with descriptions in Navy generated records where the ship’s cargo is detailed. In addition, gross measurements of the wreck are consistent with the specifications of the YF-415 such as the approximate length, and beam though an exact overall length has not been determined because most of the bow is buried in the mud. This orientation indicates that the ship most likely sank bow-first. First hand accounts of the accident reveal that one engine of YF-415 was running in forward gear as it was sinking.

Other features of the wreck such as the extension of the deckhouse running out flush against the gunwale on either side of the ship and lack of any portholes are consistent with archival photographs of the YF-415. The elliptical stern and towing bit, also observed in archival photographs, are present on this wreck. Additionally, detailed study of archival photographs have allowed the team to identify various other features common to both this wreck, and the YF-415 such as a large forward deck winch, a forward access hatch where crews quarters were located, boat davits, and a stack, which is now lying in the sand off the starboard side of the wreck. The binnacle was located in the area where the wheelhouse would be expected.

The group contacted the National Archives and Records Administration located in Washington, DC to research further. Foster located the report of the Navy inquiry, which gave a detailed description of the accident, including individual testimony. Knowles located six archival photographs, which have allowed side-by-side comparisons with video footage generated by Donna Chaston. On September 5, 2003, a letter was submitted to the Naval Historical Center’s Office of the Underwater Archaeologist to inform them of the probable discovery of the USS YF-415. We have since worked in compliance and collaboration with the United States Navy to document this wreck site, and will continue to do so as per correspondence received from the Naval Historical Center on October 7, 2003.

The depth and conditions of the site require the use of helium-based gasses to safely explore the wreck. The average operational depth on the wreck is 225 feet, and there is generally little ambient light. Bottom water temperatures ranged from 38 – 44 degrees Fahrenheit. The core team used Trimix back-gas mixtures of 17% Oxygen and 45 or 50% Helium carried in 200 – 240 cubic foot capacity double tanks. These mixes were chosen to ensure that bottom ppO2s did not exceed 1.4 ATA, and allowing for an Equivalent Narcotic Depth (END) at maximum depth equal to not more than 100 feet. The team used decompression gasses of 50% Oxygen breathed from 70 – 20 feet, carried in Aluminum 80 or 63 c.f. tanks and 100% Oxygen breathed from 20 feet to the surface, carried in Aluminum 40 c.f. tanks, with an additional safety bottle of 100% Oxygen staged at 20 feet. Custom decompression schedules were generated using programs such as Deco-Planner and V-Planner VPM-B for bottom times ranging from 18 – 27 minutes.

We would like to thank the following individuals who assisted in our efforts to explore the site and to research historical records:

Selected additional resources on the USS YF-415 Project:

- Photos of the wreck in situ as it rests today (photos by Dave Caldwell and Heather Knowles)

- Article from May 13, 1944 in the Salem Evening News

- Feature in the Boston Sunday Globe 11/9/03 on the USS YF- 415

- Feature in the Marblehead Reporter 11/20/03 on the USS YF- 415

The port side view.  The entire wheelhouse is missing, the stack is lying in the sand to the starboard side.  Note the lack of portholes and shelter deck flush with the gunwales.

The bow, the forward most part of which is completely buried in the sand.  The galley and crews quarters can be accessed through this hatch.

A view from the bow looking aft.  This area is nearly completely buried in the mud.