Thames wreck loses masts, keeps 1,500 tons of bombs

Crews have finished removing the three rusting masts from the SS Richard Montgomery, a World War II shipwreck sitting in the Thames Estuary. The vessel still holds an estimated 1,500 tons of explosives, which remain in its cargo holds. Officials stated that the engineering work is complete and the site will continue to be monitored.

The Montgomery was one of roughly 2,700 ships built in the United States to support the Allied war effort. It ran aground on a sandbar off Sheerness in August 1944. The ship was carrying munitions intended for the period following the D-Day landings. It broke apart during salvage operations and sank in the water.

For decades, the three masts extended above the waterline, serving as a visible marker for local residents and passing ships. Recent surveys indicated that the structure was deteriorating. Engineers warned that a collapse could strike the cargo and trigger a detonation. The ship has also begun to lean, increasing the concern about the masts falling onto the explosives.

Nolan Conway, a naval architect with Resolve Marine Group, noted that some of the munitions are believed to have pressure fuses. An impact from a falling mast could potentially set them off. Conway described the process of cutting the masts without shaking the wreck as the primary challenge. His team constructed a custom lifting frame to raise each mast without swinging. They also utilized a remotely operated underwater diamond-wire saw to cut the structures, eliminating the need for divers to enter the water.

U.K. maritime minister Keir Mather told the House of Commons that the project finished ahead of schedule and on budget. The total cost was just under $13 million. Mather stated that the masts placed a heavy load on the structure. Their removal reduces that risk and supports the long-term management of the site. The explosives remain because removing them would carry considerable risks of their own.

Experts disagree on the potential outcome of a detonation. Conway said estimates range from shoreline damage to a tidal wave moving up the Thames, or a minor event that closes a nearby shipping channel. He described the range of impacts as wide but noted that none of the scenarios are favorable. Officials currently judge the overall chance of an explosion to be low. The government maintains an exclusion zone around the wreck, which lies about 1.5 miles off the Sheerness coast.

The removed masts have been moved to the Historic Dockyard Chatham museum. They will be displayed there to recognize the ship's role in supporting Allied forces during the war. The Montgomery and its cargo will remain in the estuary, now entirely out of sight from the surface.