Specialized marine engineers have successfully removed all three steel masts from the SS Richard Montgomery, a sunken World War II cargo ship resting in the Thames Estuary near Sheerness, England. The delicate operation concluded in September and was officially announced by UK maritime minister Keir Mather in October 2026. Undertaken by marine salvage contractor Resolve Marine Group, the project aimed to prevent the deteriorating structures from collapsing onto the vessel’s remaining explosive cargo.
The SS Richard Montgomery was one of approximately 2,700 U.S.-built Liberty ships constructed to support the Allied war effort. In August 1944, the vessel ran aground on a sandbank near Sheerness while carrying munitions intended for troops following the D-Day landings. During subsequent salvage operations, the ship broke apart and sank just 40 miles from London. Although work crews recovered a portion of the original inventory, an estimated 1,400 to 1,500 tons of explosives and fused ammunition remain trapped inside its flooded holds.
Engineering Challenges of the Mast Removal
For decades, the ship’s three rusting masts protruded above the water’s surface as a visible landmark in the estuary. However, recent technical surveys revealed severe structural deterioration. Naval architects warned that the weight of the aging poles placed significant stress on the deck plating. This threatened to trigger an accidental detonation if the masts fell onto the live munitions below.
To safely execute the removal without vibrating or impacting the fragile hull, Resolve Marine deployed advanced engineering technology. According to naval architect Nolan Conway, engineers used a custom-built lifting frame alongside a remotely operated diamond-wire saw. The device clamped onto each mast using hydraulic arms, slicing through the steel without requiring divers to enter the water directly and preventing the poles from swaying during the lift.
Project Costs and Future Site Monitoring
The complex project was completed ahead of schedule and under its forecast budget, costing just under $13 million (£9.5 million). UK maritime minister Keir Mather told the House of Commons that eliminating the unstable masts has successfully lowered immediate structural risks and supports the long-term management of the site.
Following their extraction, the historic masts were transported to the Historic Dockyard Chatham in Kent, where conservation plans are underway to display them locally. Despite the successful stabilization work, the core danger persists. The vast majority of the explosives remain locked inside the rusting hull. Authorities maintain a strict 1.5-mile no-entry exclusion zone around the site, and the shipwreck will continue to be subjected to continuous monitoring.
Frequently Asked Questions
What is the SS Richard Montgomery?
The SS Richard Montgomery was an American Liberty ship that ran aground on a sandbank in the Thames Estuary in August 1944 while carrying wartime munitions, subsequently breaking apart and sinking.
How many explosives are still inside the shipwreck?
Experts estimate that approximately 1,400 to 1,500 tons of high explosives and fused ammunition remain trapped within the forward holds of the rusting vessel.
Why were the masts removed?
Over decades of exposure, the ship’s three steel masts deteriorated significantly. Officials removed them to prevent the heavy structures from collapsing onto the vulnerable munitions and potentially triggering a detonation.
How was the mast removal executed?
Marine salvage contractor Resolve Marine used a custom lifting frame and a remotely operated diamond-wire saw clamped on by hydraulic arms, avoiding dangerous underwater impacts to the ship’s hull.
Where are the salvaged masts located now?
The three removed masts have been relocated to the Historic Dockyard Chatham in Kent for specialized conservation and future public display.
Is the shipwreck open to recreational divers?
No. The SS Richard Montgomery is designated as a dangerous wreck under the Protection of Wrecks Act 1973, and entering the 1.5-mile exclusion zone without written government permission is illegal.
