This weapon was an unsuccessful attempt by OTO to reduce the size of the 100 mm guns for submarine use. Replaced during World War II with standard deck-mounted 100 mm/47 submarine guns.

Gun Characteristics

Designation 100 mm/43 (3.9") Model 1927
Ship Class Used On Foca and Brin classes
Date of Design 1927
Date In Service 1937
Gun Weight N/A
Gun Length oa about 170 in (4.300 m)
Bore Length N/A
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume N/A
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 2,625 fps (800 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 12,000 yards (11,000 m)

Mount/Turret Data

Designation Single Mountings
   Submarines (1): Model 1938 (?)
Weight N/A
Elevation -5 / +35 degrees
Elevation Rate Manually operated, only
Train 360 degrees
Train Rate Manually operated, only
Gun recoil N/A

Additional Pictures


"Naval Weapons of World War Two" by John Campbell
"Italian Warships of World War II" by Aldo Fraccaroli
Betasom Website Classe Brin (1936) as captured 16 August 2019


16 May 2006 - Benchmark
11 September 2011 - Corrected typographical error, redid photograph
26 May 2012 - Updated to latest template
17 August 2019 - Converted to HTML 5 format, added photographs of Brin