20 mm/120 (0.79") Meroka
Updated 18 February 2012

This is a CIWS developed by the Spanish manufacturer Bazán (now Fabrica de Artilleria Bazán - FABA) using twelve Oerlikon 20 mm/120 guns organized in two rows of six guns each.  The barrels are slightly skewed in order to expand the lethal area.

The original version of this weapon system used an off-mount radar for target search.  This handed off to an on-mount Lockheed Electronics PVS-2 Sharpshooter I-band radar which was designed to acquire targets at 5,000 m (5,500 yards), allow the CIWS to achieve first impact at 1,500 m (1,640 yards) and destroy the target by 500 m (550 yards).  An optronic system is provided for backup in a jamming environment and there is an off-boresight tracker to handle very-low flying targets.  Later, an Israeli designed IR tracker was added.  These mountings operate "open-loop," in other words, they do not correct for observed errors in the firing solution.

The current Model 2B has a more sophisticated fire control processor and a digital processor for system control.  It also includes an Indra (formerly ENOSA) thermal imager.

The Spanish Navy estimates that there is an 87% probability of destroying an incoming missile with a single 12-round burst.


Meroka CIWS
Photograph copyrighted by FABA (formerly IZAR, formerly Bazán)


Meroka CIWS
Photograph copyrighted by FABA (formerly IZAR, formerly Bazán)

Gun Characteristics
Designation Guns:  Oerlikon 20 mm/120 (0.79")
Mounting:  Meroka SPG-M2B
Ship Class Used On Principe de Asturias, Baleras and Santa María classes
Date Of Design N/A
Date In Service N/A
Gun Weight N/A
Gun Length oa N/A
Bore Length about 94.5 in (2.400 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume N/A
Rate Of Fire
(see Note)
1,440 rounds per minute cyclic (all twelve barrels)
Note:  This weapon fires two bursts per second.  Each burst consists of 4 groups of 3 rounds each.  This pattern was selected in order to minimize the recoil forces.  A burst takes 0.080 seconds to complete.
Type Fixed
Weight of Complete Round 0.71 lbs. (0.32 kg)
Projectile Types and Weights APDS-T
   0.225 lbs. (0.102 kg) with sabot
   0.191 lbs. (0.075 kg) without sabot
Bursting Charge None (solid penetrator)
Projectile Length N/A
Complete Round - 7.87 in (20 cm)
Propellant Charge N/A
Cartridge 20 x 128 mm (actual cartridge size is 128.7 mm)
Muzzle Velocity 4,232 fps (1,290 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun
(on mount)
60 rounds per barrel (720 total)

1) Bazán describes the ammunition as a special "hard-core" type designed for maximum penetration into missile bodies.

2) Penetrator has a diameter of 0.47 inches (12 mm).

Elevation With 0.225 lbs. (0.102 kg) APDS
Effective 2,200 yards (2,000 m)
Mount / Turret Data
Designation Meroka SPG-M2B
Weight 9,920 lbs. (4,500 kg) plus 928 lbs. (421 kg) off mount
Elevation -15 / +85 degrees
Elevation Rate N/A
Train N/A
Train Rate N/A
Gun recoil N/A
Data from
"The Naval Institute Guide to World Naval Weapon Systems 1991/92" and "1994 Update" both by Norman Friedman
"Defense & Armament Heracles International" Issue #54, September 1986
IZAR Press Releases
Special help by Matthew Rodchenko
Page History

21 May 2006 - Benchmark
18 February 2012 - Updated to latest template