Here is a not very known design from the Italian Navy:
During the 20s the Regia Marina also got into the "Cruiser Submarine" fad, looking for a submarine big enough to carry heavy artillery and an observation plane.
Thus, in 1926 they came with very interesting design that was supposed to be the competitor to the famouse French Cruiser Submarine Surcouf:
The Sommergibile Classe Fieramosca:
Displacement: 1965 Tn maximum
Lenght: 82,3 Meters
Armament: 8 x 533 Torpedo Tubes, 1 x 120mm cannon, 4 x 13,2 machine guns, 1 x explorer plane
Here you have the original design of the Fieramosca (1926) with an enclosed gun and hangar for the plane. However, during construction it was heavily modified losing the hangar and getting a simpler gun placement. At the end it never carried planes and in 1931 the hangar was taken out.
This is still a preliminary design, so I would appreciatte suggestions. In particular I am thinking on how to improve the heavy gun, the propeller and the diving plane.
I am also going to add a Piaggio p.8 and a Macchi M.53 seaplanes, which were supposed to be carried by the Fieramosca, althought they were never deployed.
As a reference you can check the following pages:
http://www.betasom.it/forum/index.php?/ ... osca-1926/
https://en.wikipedia.org/wiki/Italian_s ... Fieramosca
Here you go some pictures of the original and final design: