Crews Strip Three Masts From Thames Wreck at Cost of $13 Million

Crews finished removing the three rusting masts from the SS Richard Montgomery on Wednesday, completing a project intended to reduce the risk of a catastrophic explosion near London. The shipwreck, which lies roughly 40 miles from the British capital, still holds an estimated 1,500 tons of World War II munitions. Those explosives were not touched during the operation and remain in the cargo holds.

The Montgomery was one of 2,700 vessels built in the United States to support the Allied war effort. It ran aground on a sandbar off Sheerness in the Thames Estuary in August 1944 while carrying supplies for post-D-Day operations. The ship broke apart during salvage attempts and sank with its cargo intact.

For decades, the masts remained visible above the waterline, serving as a landmark for local residents and passing ships. Recent surveys showed the structure was deteriorating. Nolan Conway, a naval architect with Resolve Marine Group, the firm hired for the job, said the vessel had begun to lean. He explained that the primary concern was the masts falling onto the cargo and triggering a detonation. Some of the munitions are believed to have pressure fuses, meaning an impact could potentially set them off.

Conway stated that the main engineering challenge was cutting the masts without shaking the wreck or endangering workers. His team built a custom lifting frame to raise each mast clear without swinging. They also used a remotely operated underwater diamond-wire saw that clamps around the mast with hydraulic arms. This method allowed the cuts to be made without divers entering the water.

U.K. maritime minister Keir Mather told the House of Commons that the project was completed ahead of schedule and on budget. According to The Guardian, the total cost was just under $13 million. Mather said the masts had placed a significant load on the structure. He added that removing them supports the long-term safe management of the site.

Experts disagree on what a detonation would cause. Conway noted that estimates range from shoreline damage to a tidal wave traveling up the Thames, or a minor event that only closes a nearby shipping channel. He described the potential impacts as a large range, with none of them being good. Officials still judge the overall chance of an explosion to be low.

The government has maintained an exclusion zone around the wreck, which lies about 1.5 miles off the Sheerness coast. Mather said the site will continue to be monitored and controlled through that zone. The removed masts have been moved to the Historic Dockyard Chatham museum, where they will be displayed to recognize the ship's role in supporting Allied forces during the war.