World’s First Modern Submarine Identified In The English Channel

Photo Credit: Paul Thompson/FPG/Getty Images

Divers have discovered an extremely historically valuable submarine wreck on the seafloor of the English Channel, close to the Devon coast. This 112-year-old British vessel was the first modern submarine and set the standard for future designs.

The wreck of this submarine was known to divers and archeologists but has long been believed to be an early German U-boat. The discovery of the wreck’s true nature is of huge importance, as it was a major milestone in global submarine development.


D1 was the successor to the C-class submarines, and brought some revolutionary new features, setting the standard for submarine design from then on. It was larger, faster, more powerful, more advanced, and more maneuverable than anything before it, and like the HMS Dreadnought did in the battleship arms race, D1 gave Britain a distinct advantage in underwater warfare.

The Royal Navy D-class submarine HMS D1 on patrol near the Fort Blockhouse submarine base at Gosport circa 1910
The Royal Navy D-class submarine HMS D1 on patrol near the Fort Blockhouse submarine base at Gosport circa 1910. (Photo Credit: Paul Thompson/FPG/Getty Images)

D1’s 2,000 nautical mile range and week-long endurance meant it could actively hunt and destroy enemy ships instead of being relegated to shoreline defenses as with previous submarines.

She was longer and wider than her predecessors, making her more rugged and stable. To further increase her agility, she was fitted with two propellers. To increase offensive effectiveness, she had her torpedo tubes mounted at the bow and stern, the first British submarine to do so. This meant unlike most other submarines, she didn’t have to turn her entire hull around to fire at a target behind her.

Arguably the most significant departure from tradition by D1 was the usage of diesel engines instead of petrol or paraffin. As diesel is much harder to ignite than paraffin or petrol, she was much safer from fires or explosions.

On the surface, she would use two 600-horsepower diesel engines for propulsion, one driving each propeller, and when submerged she would be powered by two 275 horsepower electric motors instead. This gave her a surfaced top speed of 14 knots, and a submerged speed of 9 knots.

She was laid down by Vickers in 1907 and commissioned in 1909. With the launch of D1, the entire future of submarine designs would change.

She served until 1918, when despite her historic value, she was scuttled during target practice.

HMS D1 Wreck Discovery

Three years of research by divers and a U.S. historian has resulted in the conclusion that the submarine wreck off the coast of Devon is in fact D1.

Historian and author Mark Harris said, “D1 is of great historical significance because it was the original prototype for most of the British offensive submarines which fought in World War One.”

“Archaeologically, D1 is also very significant, because she is potentially the best-preserved British submarine that served in World War One.” He adds.

Imaging of the HMS/m D1 off Dartmouth
Imaging shows the location of the wreck. (Photo Credit: Wessex Archaeology)

The process of identifying the D1 has taken quite literally years, due to the complex and costly process of visiting and documenting wrecks. Many images of the wreck were scoured over and compared to original diagrams of the vessel by historians. Distinct features like the conning tower, torpedo tubes, and propellers were all used to cross-reference the wreck to plans of D1.

The reference materials were sourced by a British technical diving team led by Steve Mortimer, who worked around the wreck lower than 50 meters down.

With this information, they confirmed that the wreck was indeed D1.

U.S. historian Michael Lowrey said, “The submarine’s rudder arrangement was the main feature which convinced us that it was not a German craft.” He continued, “We then began to suspect it was a British submarine. Careful examination of other features on the vessel and a detailed study of naval records then narrowed it down.”

Dive team leader Mortimer said “Expecting to find the remains of a German U–boat, we were thrilled to discover a ground-breaking British submarine instead. It’s tremendous that D1 is now protected but divers can still visit.”

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The extremely historically valuable wreck has now been listed as a protected historic monument by the British government, which was suggested by Historic England.

Once again, this wreckage so close to the British shore highlights how many more undiscovered artifacts remain below the waves.