Submarine Surcouf and cruiser submarines of the Inter-war period

On 18th February 1942, the World's largest submarine, the French Navy's Surcouf, disappeared in the Caribbean Sea. When built, it struck terror to the hearts of the British Admiralty and the loss has been the object of much discussion with theories going from a collision at sea, deadly attack by a U.S. bomber and wild conspiracy theories! At the end of the First World War, attempts were made via the various Naval Treaties to limit the size of the major naval powers but submarines were, initially at least, left out of the proposed limitations. The Inter-War period was propice for the development of the submarine, German submarine warfare had almost brought Great Britain to its knees in the 14-18 war. The Surcouf was laid down in 1927 as a cruiser submarine and other nations were quick to follow suit. This topic presents these developments in the post-World War 1 context.

This topic is based on a talk given to the French Navy in 2012. Unless otherwide stated, all images are from our photograph collection.

The Surcouf was the largest submarine in the World when she was launched. Displacement; 3250/4,318 t surfaced/submerged, length; 110m, Range; surfaced 10,000/6,800nm at 10/13.5 kts, submerged 70/60nm at 4.5/5 kts , two 203mm guns and 10 torpedo tubes, 4 bow, 3 in two swivel mountings. She carried anti-aircraft machine guns and a light spotter aircraft in a water-tight hold. The submarine is shown here in the harbour at Casablanca, note the Besson MB.411 floatplane aft of the bridge/hangar structure and the crane used for launching and recovery, A.A. machine guns just aft of the conning tower. The rangefinder is aligned fore and aft just forward of the bridge.



The size of different submarine fleet at the opening of the First World War. It is interesting to note that Germany had a relatively small submarine fleet. Data collected from various sources including Jane's Fighting Ships 1914 and Conway's All the World's Fighting Ships 1906-1921. Maximum (red) and minimum (blue) values are given.


Prior to the war, French submarines were small and mainly for coastal and harbour defence. Here three Naďade class submarines are shown on the surface, petrol-engined with a limited speed (7.2/5.98kts) and range (200/30nm)


Thon (top left) and Anguille (bottom right) are two more Naďade class submarines launched in 1904 and stricken off the lists in 1914. They carried two 45cm torpedoes in external cradles and had a complement of 12. Displacement 70.5t surfaced, length 23.7m.


The American B2 Cuttlefish and B3 Tarantula were two of the early submarines designed by the Electric Boat Company. Here they are deck cargo on the collier Ajax for transport to the Philippines in 1912 (bottomCredit: Wright and Logan Collection, Royal Naval Museum). The early submarines had a limited range of action and were carried on ships hence submarines are referred to as boats (a boat is a vessel that is carried on a ship, as this photograph well illustrates). The K class submarine (K6, top) was an improvement on the earlier American boats but notice tha canvas screen around the otherwise open bridge. No deck gun but four torpedo tubes and an outfit of 8 torpedoes.


In an attempt to increase the speed of submarines, they were built with steam engines that were more powerful than the petrol engines. The size of the boats increased as a consequence. The boilers are lit in the French submarine Vendémiaire as it get underway, top speed was 12kts surfaced, displacement 398t/550t surfaced/submerged, length 51.1m. Diving was slow because the fires had to be put out before submerging.


Cugnot is another Pluviôse class French submarine shown here leaving the harbour at Toulon with quite a turn of speed.


The British Admiralty wanted large submarines that could operate with the battle fleet but the existing diesel engines had difficulty providing 20kts. In the K class, steam turbines were used and top speed rose to 24kts. Although an important technical achievement unmatched by other navies at the time, the class had a "difficult" career (see "The K Boats" by D. Everitt, Harrap &Co. Ltd., 1963 for a comprehensive account). Displacement has now risen to 1980/2566t surfaced/submerged for a length of 100.6m. Note the modified bulbous bow and the numerous funnel vents and air intakes all of which had to be checked before diving.


Line diagrams of a K class submarine. Note the funnels and vents which had to be meticulously checked closed before diving. The bulbous nose bow superstructure was fitted after completion in an attempt to counter a tendency for the bow to plunge under. The boat was very low when running on the surface and, being difficult to see, this was a major disadvantage when evolving with the battle fleet.

Credit: Crown Copyright


Whilst other maritime nations were struggling to develop an efficient and reliable diesel engine to be adapted to submarines, the Imperial German Navy had an operational diesel-powered submarine (the U19 class) as early as 1912. Then followed a whole host of vessels with ever increasing displacement. This photograph shows several different classes of submarine in 1915.


The development of German submarine construction led to the launching in 1917 of ocean-going, cruiser submarines of heavy tonnage (displacement: U139 class 1930/2483t, U151 class 1512/1875t surfaced/submerged). U155 was handed over to the British at the end of the war and is shown here in the port of London. Note the two 50cm guns, 2 bow tubes and 18 torpedoes.


World War 1 is over and the stage is set for the technical development and elaboration of the tactical role of submarines: monitors, cruisers and aircraft carriers. The victorious Allies were much inspired by the submarines built by Germany. However, the five powers - Britain, France, U.S.A., Japan and Italy - came together in an attempt to avoid a future arms race by limiting naval construction. The initial terms were emboded in the Washington Naval Treaty signed in 1922 but there were no specific terms concerning submarines. Two further treaties - the First and the Second London Naval Treaty (1930 and 1936, respectively) - attempted to limit submarine tonnage but there was no overall agreement and when a limit was agreed upon, it was not respected.


These graphs show the cumulative number of submarines in the respective fleets of the five naval powers over the period 1919 to 1939 and illustrated well the different policy of each nation to the limitation of submarine fleets. Italy and Japan maintained a steady production of submarines over the total period. The U.S.A. initially continued construction then slowed down during the treaty negociations before picking up new construction in the run up to the Second World War, in part as a response to the potential menace of an ever-increasing Japanese submarine fleet. The Americans were concerned about the expansion of Japan into the American sphere of influence in the Pacific. Great Britain was against all development of submarines and initially wanted to ban their construction. Constructions initially ceased prior to the treaty negociations to pick up when it became evident that submarine fleets were increasing world-wide.

Data collated from the two volumes of "Conway's All the World's Fighting Ships" for the period examined.


During the first London talks, the American newspaper, Rocherster Evening Journal, published this article which illustrates quite well the divergence of opinion amongst the naval powers as to the limitation on submarines. Great Britain wanted to ban submarine warfare saying it was "barbarous", France found the submarine to be the poor man's battleship because it was very cost-effective. The large, long range French cruiser submarines projected or existant (the Surcouf) caused much anxiety to the Admiralty and their potential impact on British commercial maritime routes.

Credit: Rochester Evening Journal, 1930


The French Navy received U139 as war reparation and renamed her Halbronn. Top right shows her with the two 50cm guns in place and underway at speed and bottom left the guns have been removed but we can appreciate the massive size of these cruiser submarines.


The U.S. Navy also had plans to build large cruiser submarines in the 1920s. This submarine was to carry eight 8 inch guns in two triple and one double turrets. The project was abandoned as the U.S.A. changed its stance on submarine warfare and aligned itself with Britain for the abolition of submarines. When construction took off again, the U.S. Navy built two Narwhal class cruiser submarines of 2987/3960t surfaced/submerged in 1927, study of the plans and other sources of information about large German submarines being consulted.

Credit: Spring Styles Book 1, United States Navy Department


U.S.S. Nautilus was one of the two Narwhal class cruiser submarines, performance was 14/6.5kts when in service and a range of 9,380 nm at 10kts. It was armed with two 6 inch guns and six 21 inch torpedo tubes.


As France maintained its position of continuing to build up an important submarine fleet, the Surcouf was laid down in 1927 and launched in 1929 but only commissioned in 1934.

Credit: Service historique de la Marine


The two 8 inch guns of Surcouf are clearly seen here, with the watertight closing mechanism at the end of each barrel. The turret itself was also watertight and could rotate, elevation was 30° but range was limited by the small rangefinder.


A monitor submarine of the Royal Navy, M-1, circa 1917. Some of the builders are on board. Note the 3 inch mark II high angle anti-aircraft gun at the stern of the boat.


Whilst the Surcouf was a new concept in submarine warfare the Royl Navy had already experience with monitor submarines of the M class. Constructed in 1917/18, the three montiors carried a single 12 inch mark IX gun taken from the stock destined for the Formidable class of pre-dreadnoughts. Elevation was 20° with a very small degree of training so essentially, the whole submarine had to be manoeuvred to align the gun with the target. As used in commercial raiding, the gun was to be fired at short range and in anything but a light sea, a hit would require a large element of luck. These monitors were also envised for coastal bombardment. M1 is photographed in the port of Anvers, 5th October 1925, these are probably some of the last photographs of M1 because six weeks later she was rammed and sank with all hands off Start Point in Devon. A second M class can be seen inboard of M1.


Whilst the negociations on naval limitation were in full swing, the Royal Navy launched, in some secrecy, an experimental cruiser submarine in 1923. It was armed with two twin 5.25 inch guns in turrets to attack convoy escorts but of course, contrary to the ban under discussion at the limitation talks, these guns could also be used against convoyed merchant shipping and hence the secrecy. The boat was not a success being plagued by engine breakdowns. Displacement: 2,820/3,700t, length: 110.8m, speed: 19.5/9kts surfaced/submerged.

Credit: Wright and Logan Collection, Royal Naval Museum


During the Inter-War period, naval aviation took a more important role in determining navy strategy. They could make reconnaissance patrols ahead of the fleet and inform on the presence of the enemy as well as spotting the fall of shot. The Surcouf carried a Besson MB.411 floatplane in a water-tight hangar in the rear part of the bridge structure. These photographs show the hangar door open (top left), the floatplane ready to be launched (bottom left) and when drawn out of the hangar and being put together. for this and the British monitor submarine M2 was converted to an aircraft carrier by


The British monitor submarine M2 was converted to an aircraft carrier by removing the gun turret and fitting a hangar and, later a hydraulic catapult. The Parnell Peto two-seater biplane had folding wings to enter the hanger (left). The U.S. Navy also experimented with submarine-borne aircraft and here a Martin MS-1 is being floated off the ballasted-down stern deck of U.S.S. S-1. The aircraft was stored in a water-tight hangar.


Let us go back to the Surcouf and here are photographs of the boat and her crew during the 1938 cruise to the French West Indies. The Surcouf was to patrol the same region in 1942 but with disastrous consequences.


With the Fall of France, the Surcouf left Cherbourg to reach Plymouth in Britain. She was refitted then re-commissioned into the Free French Naval Forces (F.N.F.L.) and made several missions notably in North America. She is shown here as 17P.


The Surcouf was in the Caribbean Sea on transit to Australia via Tahiti in 1942 when she disappeared, most probably sunk with all hands after an attack by American aircraft.


On the quay at Cherbourg, there is a memorial plaque in honour of the men lost in the sinking of the Surcouf. 130 officers and men died, including the British Liason officer Lieutenant Burney, R.N.V.R., Leading Signalman Warner and Telegraphist Gough.