Modern French 100 mm naval guns are multipurpose artillery pieces (anti-air, anti-ship, ground), capable of a high rate of fire. Most modern French warships are equipped with one of its versions.
At the end of the Second World War
, the French Navy was equipped with numerous calibres, most of which were due for retirement. In 1953, the STCAN of Paris, under engineer Tonnelé, drafted the design of a polyvalent 100 mm gun. The gun was designed to be effective for
- anti-air defence
- anti-ship combat
- ground shelling
The first turret of the family, "modèle 53", was tested at sea on the escort Le Brestois in 1958 and the escort aviso Victor Schoelcher in 1961.
The most common version, modèle 68
, is completely automatic. Two crew are in the turret:
- the gunner, to the left of the gun, uses a joystick to point the gun, and optic ranging and aiming instruments to direct the fire
- the observer monitors the operations from the back of the turret.
The ammunition is stored underneath the turret, and fed to the gun by a lift regularly manned by two crew. A flexible pipe allows feeding the gun under any orientation.
The round is introduced automatically and the empty shell is ejected after the shot through an evacuation door on the front of the turret. Cooling is provided by water circulating in layers of steel around the tube of the gun, and by an injection of air and water after every shot.
The turret can be used under three modes:
- Telecommand by the main firing computer, from the Operation Central
- Telecommand from a secondary firing computer
- Manual control by the joystick at the left of the gun (except the 100TR version)
Aiming is done by two electric motors, one for the elevation (left of the turret) and the other for the horizontal rotation (right of the turret). Two hydraulic systems feed the gun. The gun can also be moved manually for maintenance.
Since it is usually installed on the forward deck of warships, these turrets are often exposed to breaking waves and humidity. To prevent corrosion and mechanical problems, the turret is made water-tight by rubber joints. The gun itself is sealed by a rubber tampion (muzzle plug), which can be shot through in case of emergency.
The plexiglas viewbay used to manually aim the gun is usually protected by a steel cover.
The 100 mm turret undertook several improvements:
- Better automatisation and increase of the firing rate
- Use of new ammunition optimised to shoot down missiles
- Compatibility with modern firing computers
Three main versions of French 100mm guns can be cited.
- modèle 53: the first shell had to be fed manually, with subsequent shots taking advantage of recoil to load automatically, firing at up to 60 rounds per minute. Employs electro-mechanical fire control, with two manual command stations on the front of the turret.
- modèle 64, direct offspring of the 53, with a 78 round/min rate of fire. This version can be connected to modern firing computers.
- modèle 68 In this model, the turret was lightened and can load the first round automatically, but rate of fire is reduced back to 60 rounds per minute. This version may operate unmanned with only one manual station remaining as a backup. This is later improved to CADAM (Cadence Améliorée, "improved rate of fire"), with an increase to 78 rounds/min.
- modèle 100 TR (used on the La Fayette class frigates), mechanically similar to the 68, but with a stealth armour. The manual control has been removed.
- Compact: This weapon has only been exported to China, Malaysia, Portugal and Saudi Arabia. It is even lighter than the modèle 68, at only 19 metric tons including gunhouse, deck and magazine. Later Mk 2 versions also fire faster, at up to 90 rounds per minute. However, it is also limited to firing short bursts of no more than 6 rounds.
The 100 mm gun has been used in the French navy on most warships equal or greater than avisos
. The Charles de Gaulle
, with her MBDA Aster
-only defence, is the main exception. Also, the future Horizon CNGF
frigates should be equipped with the 76 mm Oto-Breda gun
. It is not yet known whether this is a general tendency to abandon the 100 mm gun, or only a temporary trend.
The 100 mm has been sold abroad, and is used by the navies of Belgium, Portugal, Turkey, Brazil, Saudi Arabia, Taiwan and others.