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Book Review – X.1: The Royal Navy’s Mystery Submarine

By Roger Branfill-Cooke; Naval Institute Press; 192 pages

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In 1901, a British admiral reportedly denounced submarines as “underhand, unfair and damned un-English.” At the 1921 Washington Naval Conference, British diplomats argued for total prohibition of submarines, but the French refused. Political elites and naval staffs were conflicted over the issue of “unrestricted submarine warfare.” Since the age of sail, international law had insisted that warships stop, board, and inspect merchant vessels before sinking them, only after ensuring that crews were “in a place of safety.” Cruisers on the high seas could observe such niceties, but for submarines, surviving on stealth, it was impractical, even suicidal. It was these considerations that led to the Royal Navy’s interest in “cruiser” submarines, reports Roger Branfill-Cooke in X.1: The Royal Navy’s Mystery Submarine.

HMS X.1

A Finnish photograph of the Royal Navy cruiser submarine X.1, circa 1927.
Photo: Hakkapeliitta N:o 40

In 1916, the Imperial German navy ordered the U-139 class: large, long-range, “cruiser submarines.” With two 150 mm deck guns, and a precision rangefinder in an armored conning tower, it could fight surfaced as well as submerged. After the war, with Germany forbidden by the Versailles Treaty to operate submarines, the U-139s were divided among the Allies and carefully studied, strongly influencing submarine design between the wars.

Traumatized and nearly bankrupted by the war, Britain was in no mood for military innovation during the 1920s. Nevertheless, the Royal Navy built some “experimental” ships. Cruiser submarine HMS X.1, designed and built in secrecy and scrapped before World War II, has largely escaped the notice of naval analysts and historians. This book tries to fill that gap, based on long-neglected official records and surviving firsthand accounts.

 

HMS X.1

X.1 was the largest, most heavily armed submarine in the world when launched on Nov. 16, 1923. The concept of operations was to surface suddenly in the middle of an enemy convoy and open fire to knock out any escorts before finishing off the transports. The broad beam and great size of the vessel made her a stable gun platform, keeping the guns well above the waves. The open gun mounts were not watertight; gun crews had to climb up to their positions after surfacing. An inflatable rubber seal between the hull and the rotating gun mounts proved surprisingly effective. The fire control tower carried an advanced 9-foot (2.7-meter) rangefinder.

X.1: The Royal Navy’s Mystery Submarine

X.1: The Royal Navy’s Mystery Submarine,
by Roger Branfill-Cooke; Naval Institute Press; 192 pages

From the beginning of her career, X.1 was a hard-luck ship, dogged by mechanical breakdowns and accidents. The book narrates these in painful detail. The badly designed diesel engines proved nearly impossible to maintain. Although X.1 handled well underwater, particularly after installation of a second set of bow planes, she spent much of her short service life dockside, under repair. In 1931, she was damaged in dry dock when carelessly installed supports collapsed and she fell over on her side. In the depths of the Great Depression, the admiralty decided X.1 was not worth repairing.

Chapters of the book review the history of “giant” submarines, the design criteria for X.1, her ill-fated propulsion machinery, handling, armament, hull and fittings, operational history, life aboard, and her final sad fate. An excellent chapter outlines the cruiser submarine types built, or projected, by the United States (Narwhal), France (Surcouf), Japan (I-400), and Germany (Type XI U-boat).

Traumatized and nearly bankrupted by the war, Britain was in no mood for military innovation during the 1920s. Nevertheless, the Royal Navy built some “experimental” ships. Cruiser submarine HMS X.1, designed and built in secrecy and scrapped before World War II, has largely escaped the notice of naval analysts and historians. This book tries to fill that gap, based on long-neglected official records and surviving firsthand accounts.

The book is richly illustrated with drawings and rare photographs, many never previously published. Unfortunately, an appendix of ships’ plans reproduced from the original 1/48-scale blueprints has lines so small and faint that they are only legible with a magnifying glass.

Another detailed appendix provides extracts from the ship’s surviving log books.

X.1: The Royal Navy’s Mystery Submarine will be of great interest to readers who are submariners, naval enthusiasts, or historians of military technology. It describes a lost era: before advances in radar and sonar made the life of the submariner more precarious; before the snorkel, acoustic quieting and ultimately, nuclear propulsion, turned submersible boats into true submarines. It offers a unique glimpse into an unhappy period of the Royal Navy’s epic history.

HMS X.1

  • Displacement: 2,780 long tons (2,820 tons) surfaced; 3,600 long tons (3,700 tons) submerged
  • Length: 363 feet, 6 inches (110.79 meters)
  • Beam:  29 feet, 9 inches (9.07 meters)
  • Draft: 15 feet (4.6 meters)
  • Propulsion: 2- x 8-cylinder Diesel engines, 3,000 horsepower (2,200 kW) total 2 x auxiliary Diesel engines, 1,200 horsepower (890 kW) 2 x electric motors, 1,000 horsepower
  • Speed: 19.5 knots (36.1 kilometers/h; 22.4 mph) surfaced 9 knots (17 kilometers/hour) submerged
  • Armament: 6 x 21 inch bow torpedo tubes, 12 torpedoes, 4 x 5.2 inch/42 (132 millimeters) guns in two twin mounts, 100 rounds per gun, maximum range 16,000 yards (15 kilometers)

Note: there is an early 1930s newsreel film clip of X1 under way: http://www.liveleak.com/view?i=ed7_1298851494