The French 100 mm naval gun is a polyvalent artillery piece (anti-air, anti-ship, ground), capable of a high rate of fire. Most modern French warships are equiped with one of its versions.

History

At the end of the Second World War, the French Navy was equiped with numerous calibers, 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 familly, "modèle 53", was tested at sea on the escort Le Brestois in 1958 and the escort aviso Victor Schoelcher in 1961.

Description

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 surviewer monitors the operations from the back of the turret.

The ammunition is stoked 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 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.

Versions

The 100 mm turret udertook several improvements:

• Better automatisation and increase of the firing rate
• Use of new ammunition optimised to shoot down missiles
• Compatibility with modern firing computers

Four main versions of the turret can be cited:

• modèle 53: the first shell had to be fed manually (the next ones were fed automatically). Two manual command stations onthe front of the turret.
• modèle 64, direct offspring of the 53, with a 78 round/min rate of fire. Can be connected to modern firing computers.
• modèle 68 CADAM (Cadence Améliorée, "improved rate of fire"), entirely automatic and unmanned. Only one manual station remains in case of emergency.
• 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.

Usage

The 100 mm gun has been used in the French navy on most warships equal or greater than avisos. The Charles de Gaulle, with its Aster 15-only defence, is the main exception. Also, the future Horizon CNGF frigates should be equiped 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 some comfortable success with export, and is used by the navies of Turkey, Brazil, Saudi Arabia, Taiwan and others.

External links

• Le canon de 100mm (Netmarine.net)

100 mm modèle 64 turret of the Clémenceau	100 mm modèle 68 turret on the Germinal	100 mm modèle 68 turret on the Prairial	100 mm turret on the La Motte-Picquet
100 mm modèle 68 turret on the Primauguet	100 mm modèle 68 turret on the Tourville	the La_Fayette_class_frigate FS_Surcouf with her modèle 100 TR	the La_Fayette_class_frigate FS_Courbet with her modèle 100 TR