37 mm/70 (1.46") AA Gun Model 1935
Updated 14 December 2009

Experiments with the semi-automatic 37 mm Model 1933 AA gun resulted in the much improved fully automatic Model 1935 which was designed by the Artillerie Navale at Ruelle.  However, this weapon did not finish development before the French surrender in 1940.  One of the few prototypes was mounted on the old Patrol Sloop Amiens and was apparently successfully used during the Dunkirk evacuation.

Each gun had a pusher hoist for the six-round magazines.  A remote director with a 2-meter rangefinder was used for RPC together with Sautter-Harlé electric servo-motors.  However, the guns were controlled only in train, elevation was still manually operated.  For some ships, including Richelieu, it was planned to have each director control two twin mounts.

A note on sources:  In "Naval Weapons of World War Two" this gun is described as being 48 calibers long while in "French Battleships:  1922 - 1956" it is described as being 70 calibers long.  From an examination of the photographs below and those of the 37 mm/50 Model 1933, I have decided that 70 calibers is probably correct.

There was one further 37 mm gun that was under consideration at the time the war started, the 37 mm zénithaux (zenith).  This was a Hotchkiss design for a quadruple mounting intended for use against dive bombers.  This mounting was unusual in that the guns could not depress past +45 degrees.  The mounting would have been countersunk in the deck and loaded from beneath, similar in concept to the British BD (Between Deck) designs.  The surrender of France in 1940 halted development and this weapon never made it off the drawing board.

Unless otherwise noted, the data that follows is for the 37 mm Model 1935.


37 mm/48 Model 1935 on Patrol Sloop Amiens in 1942
Note the remote director for this weapon directly above the small boat


Sketches and close-up view of Amiens Mounting
Images courtesy of John Schaefer

Gun Characteristics
Designation 37 mm/70 (1.46") AA Gun Model 1935
Ship Class Used On Patrol Sloop Amiens (Prototype)
Richelieu and Dunkerque classes (Planned)
Date Of Design 1933
Date In Service 1936
Gun Weight 3,200 lbs. (1,450 kg)
Gun Length oa N/A
Bore Length N/A
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume N/A
Rate Of Fire
(see Note 2)
Cyclic:  165 - 172 rounds per minute
Practical:  N/A (I would guess about 60 - 100 due to barrel life considerations)

1) The magazine boxes were inserted horizontally into a continuous feed mechanism which was located at the trunnion axis.

2) Very high rates of fire were achieved with the single gun prototype.  In early trials at Sevran, several bursts of 100 rounds were fired in under 36 seconds at zero elevation.  Bursts of 150 to 170 rounds were fired at angles between zero and 70 degrees of elevation, including one continuous burst of 142 rounds.  However, such high firing rates wore out the barrels in just a few minutes.  See below.

Type Fixed
Weight of Complete Round N/A
Projectile Types and Weights HE - 1.83 lbs. (0.83 kg)
Bursting Charge 1.76 oz (50 g) HMn
Projectile Length N/A
Propellant Charge 0.46 lbs. (0.21 kg) "special Hotchkiss"
Muzzle Velocity 2,707 fps (825 mps)
Working Pressure 19.0 tons/in2 (3,000 kg/cm2)
Approximate Barrel Life
(see Note)
600 rounds
Ammunition stowage per gun N/A
Note:  As mentioned above, barrel life was very short with these weapons due to the high working pressures and the figure above was the best achieved after intensive efforts with metallurgy.  The long development cycle for these weapons was mainly related to efforts to increase life.  Water-cooling was under investigation at the time of the French surrender.
Elevation With 1.83 lbs. (0.83 kg) HE Shell
Maximum Range @ 45 degrees 8,750 yards (8,000 m)
Mount / Turret Data
Designation Twin and Quad Mounts Planned
   Twin Mount Prototype:  ACAD Mle 1936
Weight  Twin Mount:  17,800 lbs. (8,070 kg)
Elevation -10 / +85 degrees
Elevation Rate Manually operated, only
Train 360 degrees
Train Rate N/A
Gun recoil N/A
Notes:  The twin-gun prototype on Amiens is described as a base ring type.  There was a working chamber or lobby under the mounting from which twin continuous belt hoists rose to the guns.  Loaders in this chamber fed cartridge boxes stored in ready racks into the hoists.  The guns apparently ejected the empty boxes onto a slide which dumped them out the back of the mounting.
Data from
"Naval Weapons of World War Two" by John Campbell
"Battleships:  Allied Battleships in World War II" by W.H. Garzke, Jr. and R.O. Dulin, Jr.
"French Battleships:  1922 - 1956" by John Jordan and Robert Dumas
"Navies of the Second World War - The French Navy" by Henri le Masson
Page History

22 May 2008 - Benchmark
14 December 2009 - Added information on ROF, mounting, RPC arrangements, barrel life and zénithaux design