The SS Richard Montgomery is – or rather was – a mass-produced American cargo vessel known as a Liberty ship, measuring some 135 metres from bow to stern. It's now an 80-year-old shipwreck which, depending on your view, is either an unusual wartime relic or a ticking time bomb.
Built in a shipyard in Jacksonville, Florida, it was launched in 1943. Like all Liberty ships, it was involved in the war effort and the following year saw it loaded with around 7,000 tonnes of US-made bombs and other munitions for use by the Allies in Europe.
On what would be its final voyage, it departed from Pennsylvania in mid-August 1944. Bound ultimately for Cherbourg in Normandy, the ship crossed the Atlantic before reaching British waters, where it was instructed to wait off the coast of Kent, with a view to joining a convoy heading across the Channel to France.
Before it could do so, however, heavy weather on 20 August forced the giant ship to drag its anchor into shallower water, where its keel stuck fast in a sandbank. The ship has stayed there ever since – sunken, abandoned and now split in half – its three masts poking above the waves and its holds still partly laden with ordnance.
Cause of consternation
The wreck sits in around 15 metres of water in the Thames Estuary, just a mile and a half off the seaside town of Sheerness on Kent’s Isle of Sheppey. It’s now been there for more than eight decades, but its presence is still a cause of consternation for some. There is a no-entry exclusion zone around the wreck and a darkly humorous mural at Sheerness, which shows a mermaid reclining on a beach with a detonator, beside the words ‘Welcome to Sheerness – you’ll have a blast’.
When the ship first grounded, a team was dispatched to unload as much of its explosive cargo as possible. A crack in the hull soon appeared, however, flooding the vessel and bringing the salvage effort to a halt after just a month. A whopping 1,400 tons of munitions remain in the wreck, including almost 300 enormous ‘blockbuster bombs’ and more than 2,500 cluster bombs. What would happen if they were to explode is a question that’s been asked since 1944.
“There was an analysis done by the Royal Military College of Science that said the ‘top event’ would involve a 3,000-metre-high column of water, sand and debris, and a five-metre-high tsunami,” says Professor David Alexander, a University College of London academic specialising in risk and disasters. The idea of a cataclysmic blast followed by a tidal wave bearing down on the coast – then powering down the estuary towards London – is a sobering one.
“But it really is highly unlikely that we would get the ‘top event’. What we might get is a situation of absolute instability, in which there are smaller explosions and the whole thing becomes ungovernable,” he adds. In terms of the chances of this actually happening, Professor Alexander explains it’s almost impossible to say in any authoritative way. “Mainly because we haven’t much idea of what is actually going on inside the wreck.”
The ship’s three protruding masts have reportedly begun to wobble in recent years, leading to the worry that they may collapse and destabilise the bombs in the hold. A few years ago, a government tender was put out to remove the masts. A Scottish company subsequently won the contract in 2021, with a plan to put gantries around the masts and lift them off. However, the myriad risks involved – including numerous bombs that have tumbled free from the snapped hull and now rest nearby – mean the work has still not taken place.
As for other potentially dangerous wrecks around the UK coast, of the 37,000 or so shipwrecks in British waters, only two are officially designated as dangerous: the SS Richard Montgomery and the SS Castilian, a weapons-carrying steamship that sank off Anglesey in 1943. Elsewhere, a large sea trench known as Beaufort’s Dyke – stretching between Northern Ireland and Galloway – was dumped with thousands of tons of surplus munitions at the end of the Second World War. They remain there today.
Top image: The Government have put out a tender for the masts to be cut off the dangerous shipwreck SS Richard Montgomery in the Thames. The WW2 wreck sank in 1944 with 1,400 tonnes of TNT still onboard. Credit: James Bell/Alamy Live News
