Author Topic: HM Submarine X1 (1923 - 1936)  (Read 1911 times)

Offline Smiffy

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Re: HM Submarine X1 (1923 - 1936)
« Reply #2 on: December 10, 2019, 10:40:09 PM »
There's another one here that shows her leaving Chatham Dockyard:
 


Offline stuartwaters

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HM Submarine X1 (1923 - 1936)
« Reply #1 on: December 10, 2019, 08:43:41 PM »

HMS X1 was an experimental Submarine Cruiser built by the Royal Dockyard at Chatham. She was the only Submarine Cruiser built for the Royal Navy and at the time of her launch and for a few years afterward, she was the largest submarine ever built. HMS X1 remains the largest submarine to be built at Chatham and until the launch of the nuclear powered HMS Dreadnought in 1960, HMS X1 was the largest submarine ever built for the Royal Navy. She remains the largest non-nuclear powered submarine in the history of the Royal Navy.


The Submarine Cruiser was originally a German idea. In 1916, the Germans had built the three submarines of the U139 class. These boats, displacing 2,400 tons dived and armed with 6 x 21in torpedo tubes (4 bow, 2 stern), carried a pair of 150mm (5.9in) guns as well as a pair of 88mm (3.5in) guns. Not only did they carry enough fuel to be able to sail for 17,750 miles on the surface at 8 knots, but their guns were powerful enough to be able to drive off any convoy escort. The British already had some experience with large submarines carrying heavy guns, gained with the three submarines of the M Class. These boats were armed with a single 305mm (12in) gun, but were intended as Submarine Monitors, tasked with bombarding targets ashore with their massive gun which could be fired with the boat submerged and just the muzzle of the gun out of the water.


After the Great War ended, the other major powers looked into the construction of large, heavily armed submarines with a truly global range and HMS X1 was the British attempt to build one. In 1926, the French Navy launched the Surcouf, an even larger boat armed with 8in guns and which even carried a small folding aeroplane in a hangar astern of the conning tower. In the late 1920s, the United States built USS Narwhal and USS Nautilus, both large submarines armed with 152mm (6in) guns.


In 1922, Britain had signed up to the Washington Naval Treaty. This had been triggered by the beginnings of a new arms race with both the UK and the USA planning even larger fleets of increasingly large and powerful warships, especially Battleships. In the negotiations which preceded the Treaty, the British had demanded that submarines be banned altogether, in the light of the damage inflicted on their Merchant Marine by the German policy of unrestricted submarine warfare. The French objected strongly to this idea, so a compromise was reached whereby the use of submarines to attack merchant ships was banned instead, which was exactly the reason why the Submarine Cruiser was invented in the first place.


It is not suprising then, that HMS X1 was built and launched under a degree of secrecy, with the British Government going to the trouble of having a Court Injunction against the newpapers of the day publicising the boat's launch and even going so far as to seize all copies of newspapers bearing pictures of the new submarine. 


HMS X1 was ordered under the 1921/22 Naval Estimates and her first section was laid on the No.7 slipway at Chatham on the 2nd November 1921. The boat was launched into the River Medway by Mrs Kibble on the 16th November 1923.


HMS X1 was commissioned during December of 1923 and on completion was a technological marvel. She displaced 2,820 tons on the surface and 3,600 tons submerged and as such, was more than twice the size of any submarine yet built for the Royal Navy. Manned by a crew of 10 officers and a hundred ratings, she was armed with 4 x 5.2in guns in unarmoured, powered, twin turrets, one on a raised casing forward of the conning tower and one aft of it. These guns had a range of about 16,000 yards and were sighted using a 9ft rangefinder located behind the bridge. The rangefinder could be raised 8ft. The fire control director itself was in the middle of the conning tower and the top part of it could also be raised, by two feet. The turrets themselves could be operated with the casing awash, giving the boat a much lower profile making for a smaller target for escorting vessels to aim at.  In addition to her main guns, the boat was fitted with a pair of 0.303 (7.7mm) machine guns. In addition to her guns, HMS X1 was fitted with 6 x 21in torpedo tubes, themselves taken from cancelled L Class submarines ordered during the Great War. The boat had sufficient space in her torpedo room to carry a reload torpedo for each tube.


HMS X1 in the River Medway with Chatham Dockyard in the background:





HMS X1 was powered on the surface by a pair of Admiralty 8 cylinder 3,000shp diesel engines. A further two 1,200shp MAN diesel generators were fitted to charge her batteries, which themselves powered a pair of 1,000shp GEC electric motors. The generators had been taken from a surrendered German submarine, U126. The batteries themselves were a new innovation, being cooled, by the cells being fitted with fins with coolant water being circulated around them. The main engines could drive the boat to a speed of almost 20 knots on the surface and 9 knots dived. She carried enough fuel in tanks located between the inner pressure hull and her outer hull to be able to sail for 12,400 miles on the surface at 12 knots and 18,700 miles at 8 knots. Her endurance dived was in line with boats of her era, having a range of only 50 miles at 4 knots before needing to surface and recharge the batteries.


Operating such a large submarine submerged would have brought it's own problems and to eliminate any potential underwater handling problems, she was fitted with retractable, forward hydroplanes in a biplane configuration. And large she certainly was. Aside from being a submarine displacing 3,600 tons submerged, the boat was 363ft 6in long and 29ft 9in wide across the beams. Surfaced, she drew 15ft of water.


A model of HMS X1, showing the unusual but very effective biplane forward hydroplanes:





A model of HMS X1 showing her running, decks awash with just the conning tower and guns exposed. This is how the boat was intended to engage a convoy escort:





After her launch, HMS X1 proceeded to sea trials in the Thames Estuary and North Sea. These proved the boat's submerged handling to be docile. Despite her size, she proved to be manoevrable and easily controlled. The biplane layout of her forward hydroplanes meant that she performed within expectations. After commissioning, HMS X1 was sent to the Mediterranean, operating out of Malta.


HMS X1 at Malta:





HMS X1 on the surface, bows-on view:





HMS X1 on the surface, a nice broadside view:





HMS X1 was to spend her entire operational career in the Mediterranean Sea. Despite her potential, she spent almost as much time in Dockyard hands as she did at sea. The main problem was with the vertical driveshafts from her main motors to her propeller shafts. These were damaged on numerous occasions, although that wasn't the only problem. On one occasion, the crankshaft in one of her diesel generators broke. It is not certain how the Dockyard managed to source a replacement given that the engine had been taken from a surrendered U-Boat. It is thought that they managed to weld the crankshaft back together. Although the boat handled well in all respects, she was not an easy boat to serve on for her crews. In 1930, her Commanding Officer reported that the accomodation was cramped, ventilation poor and there was excessive humidity and condensation in the boat.


After only four years in service, HMS X1 was laid up later in 1930 and was broken up in Pembroke in 1936. The British never built another Submarine Cruiser, although other nations did, as mentioned above. The Germans went so far as to design the Type XI U-Boat, a very large submarine of 4,650 tons submerged,  also carrying four 128mm guns in powered turrets like HMS X1. Like the giant French submarine Surcouf, they were also intended to carry a small, folding floatplane. Three of these monsters were laid down in 1939, although they were all cancelled before completion, on the outbreak of the Second World War.


HMS X1 is the subject of the book "X1 - The Royal Navy's Mystery Submarine" by Roger Branfill-Cook, available here:
https://www.amazon.co.uk/X-1-Royal-Navys-Mystery-Submarine/dp/1848321619


Silent newsreel footage of HMS X1 can be seen here:
"I did not say the French would not come, I said they will not come by sea" - Admiral Sir John Jervis, 1st Earl St Vincent.