Les sous-marins
Bouchor Joseph-Félix
Dunkerque, décembre 1916 Musée national Blérancourt
The French Navy
Submarines in 1939 / 1945
French submarines and the Second World War
In 1939, when the war broke out, France had a very modern submarine fleet which comprised 1st class large patrol submarines of 1500 tonnes such as the Narval or the Casabianca.
Given that the concept of a submarine cruiser was developed by France, its 4000 tonnes Surcouf was a real technological success.
The Surcouf had 4 front 550 mm 1917 model tubes, 2 triple 1925 OSD turrets comprising one 550 mm tube and two 400 mm tubes, eighteen 550 mm torpedoes, four 400 mm torpedoes, 640 shells, two 203.2 mm cannons on double turrets, two 37 mm cannons and four 8 mm 1914 model Hotchkiss machineguns.
In addition, this submarine carried one observation seaplane, type BESSON M.B 411, weighing 765 kg, powered by a SALMON AC9 engine, capable of flying 7 hours at 130 km/h. Under calm maritime conditions, 30 minutes sufficed to remove it and get it into action.
The U.S. aviation mistakenly sank the Surcouf in the Pacific, killing 134 persons.
On its part, the Kriegsmarine used considerably modernized U-Bootes (Untersee Boote). These dreadful sea wolfs alone sank 12 million tonnes of Allied merchant boats.
The genesis of the anaerobic submarine...
With regards to technical developments during this period in the domain of submarines, it is worth recalling that the schnorchel was designed by the Reich, and the asdic by the Allies. One invention which has lingered on till date is the hydrogen peroxide Helmuth Walter turbine. The last generation submarines of the Reich were equipped with this turbine, like the famous XXI and XXII which when navigating under water could attain the velocity 25 knots. This was the genesis of the anaerobic submarine.
Newly born also was the “intelligent” torpedo LUT which would start off in a straight line and then adopts a sequence of unpredictable trajectories, enabling it to inexorably break the targeted convoy. Other inventions in the same line include the “casse destroyer” torpedo, used to destroy low draught ships, and the magnetic firing torpedo which detonated when passing beneath a torpedoed ship.