A slightly improved version of the 100 mm/47 Model 1928 specifically intended for submarines but also used on a few auxiliary vessels. Manufactured by OTO. Slightly shorter than the other 100 mm/47 guns.

Gun Characteristics

Designation 100 mm/47 (3.9") Models 1931, 1935 and 1938 for Submarines
Ship Class Used On Glauco, Marcello, Cappellini, Liuzzi, Marconi, Cagni, Sirena, Perla, Adua, Argo, Acciaio and Flutto classes
Foca and Brin classes as rearmed
Date of Design 1931, 1935 and 1938
Date In Service 1932
Gun Weight N/A
Gun Length oa 194.5 in (4.940 m)
Bore Length N/A
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume 473.5 in3 (68.79 dm3)
Rate Of Fire 8 - 10 rounds per minute


Type Fixed
Complete Round Weight N/A
Projectile Types and Weights HE: 30.4 lbs. (13.8 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge N/A
Muzzle Velocity 2,756 fps (840 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun N/A


Range with 30.4 lbs. (13.8 kg) HE
Elevation Distance
35 degrees 13,800 yards (12,600 m)

Mount/Turret Data

  • Single Mountings
    • OTO 1932
    • Others?
Weight 4.6 tons (4.7 mt)
Elevation OTO 1932: -5 / +32 degrees
Others: -5 (?) / +35 degrees
Elevation Rate Manually operated, only
Train 360 degrees
Train Rate Manually operated, only
Gun recoil N/A

All submarines carried one of these guns.

Additional Pictures


Data from:

  • "Naval Weapons of World War Two" by John Campbell
  • "Italian Warships of World War II" by Aldo Fraccaroli
  • "Marconi Class Submarines at War" article by Pierre Hervieux in Warships Volume VIII


07 December 2007
23 September 2012
Added picture of museum