Thames Wreck Masts Removed; 1,500 Tons of Bombs Remain

Crews have removed the three masts from the SS Richard Montgomery, a World War II shipwreck in the Thames Estuary that still holds an estimated 1,500 tons of explosives. The operation, completed this week, was designed to reduce the risk of the deteriorating structure collapsing and triggering a detonation. The munitions themselves remain undisturbed on the seabed.

The Montgomery was one of approximately 2,700 vessels built in the United States to support the Allied war effort. It ran aground off Sheerness in August 1944, about 40 miles from London, while carrying munitions intended for use after the D-Day landings. The ship broke apart during salvage attempts and sank with its full cargo.

Nolan Conway, a naval architect with Resolve Marine Group, stated that the vessel had begun to lean. He warned that the masts could have fallen onto the cargo, causing it to detonate. Conway noted that some of the munitions are believed to have pressure fuses, making them sensitive to impact.

The engineering team constructed a custom lifting frame to raise each mast without swaying. They used a remotely operated underwater diamond-wire saw to cut the masts free, eliminating the need for divers to enter the water. The goal was to prevent any vibration from shaking the wreck.

U.K. maritime minister Keir Mather told the House of Commons that the project was finished ahead of schedule and within budget. The cost was just under $13 million. Mather said the masts had placed a heavy load on the structure, and their removal reduces that risk.

The masts have been moved to the Historic Dockyard Chatham museum, where they will be displayed. The explosives remain in place because removing them carries considerable risks. Conway said estimates for a potential detonation range from minor shoreline effects to a tidal wave traveling up the Thames. Officials continue to judge the overall chance of an explosion as low.

The government has maintained an exclusion zone around the wreck, which lies about 1.5 miles off the Sheerness coast. Mather confirmed that the site will continue to be subject to continuous monitoring and control through that zone.