FS Surcouf

FS Surcouf Take a foldable seaplane, destroyer designed torpedo launchers, 2x 6inch cruiser guns and throw them all together and this is what you get. Only the French could achieve this level of design insanity

Launched on 18 November 1929 with a length of 110M FS Surcouf was Frances answer to the British built M1 class submarine that mounted a 12 inch battleship gun into a submarine stood back and watched what happened. Promptly sinking and not in the usual way.

Surcouf improved on this design by having two smaller calibre 6 inch guns intended for a light cruiser, fitted them into a pressurised rotatable turret and built a submarine to fit it to. To aid in range spotting and target identification at range they also fitted the sub with a small hangar at the rear of the conning tower structure to house a single folding seaplane.

The principle behind this sub was to get close to a target while submerged. Surface close to the target by surprise, open the end covers of the gun barrels and fire at close range before submerging again to reload and relocate to prevent being fired upon.

Shortly after being commissioned France surrendered to Germany and Surcouf escaped to the UK to prevent falling into enemy hands. British submariners claimed the sub was a floating death trap and simply refused to use the sub. Leaving it to a skeleton crew of French freedom fighters to take custody of the sub.

While on operations near the Americas Surcouf sank with all hands leaving no trace of the submarine. Her wreck or crew have never been found though there are several possible instances of submarines being sunk in the area at the appropriate time there is no concrete evidence to indicate any of then were Surcouf.

In addition to the main guns the sub also had the conventional bow mounted torpedoes situated in four horizontal tubes but also had two hull mounted torpedo launchers that could rotate out from within the hull to fire sideways for a broadside of 5 torpedoes at once. These torpedo launchers could not be reloaded from within so needed a harbour to reload them.

The sub also had two machine guns fitted atop the aircraft hangar for some light AA defense.

This submarine at the time of it's launch was the largest submarine in the world until the Japanese I-400 aircraft carrier submarine was launched later in the war.