This mounting was originally developed by Emerson Electric as the EX-74 and was intended to arm the US CPIC coastal patrol boats, of which only a single prototype was ever built. The CPIC boat used a GFCS Mark 93 which incorporated the Kollmorgen Mark 35 periscope director.

With the cancellation of the US CPIC program, Emerson then further developed this weapon into an export version and has successfully sold them around the world.

This weapon system uses the Oerlikon 30 mm/75 KCB cannon which is also used on the British GCM and LS-30B weapon systems.

Gun Characteristics

Designation Oerlikon: 30 mm/75 KCB
USN: 30 mm/75 Mark 28
Ship Class Used On USN: CPIC Coastal Patrol Boat

Exported to Ecuador, Ethiopia, Greece, Malaysia, Nigeria, Philippines, South Korea and Taiwan

Date Of Design Gun: 1968
Mounting: 1975
Date In Service N/A
Gun Weight N/A
Gun Length oa N/A
Bore Length about 88.6 in (2.250 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume N/A
Rate Of Fire Cyclic: 600 rounds per minute


Type Fixed
Weight of Complete Round N/A
Projectile Types and Weights HE: 0.93 lbs. (0.420 kg)
APDS: 0.66 lbs. (0.300 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge N/A
Muzzle Velocity HE: 3,543 fps (1,080 mps)
APDS: 3,854 fps (1,175 mps)
Working Pressure N/A
Approximate Barrel Life about 5,000 rounds
Ammunition stowage per gun
(on mount)
985 rounds


Range with 0.93 lbs. (0.420 kg) HE
Elevation Range
Effective range - anti-surface 10,900 yards (10,000 m)
Effective range - anti-air 3,000 yards (2,750 m)

Mount/Turret Data

  • Twin Mounting
    • USN: Mark 74 (EX-74)
    • Export version: Emerlec-30
Weight Without ammunition: 4,156 lbs.
With ammunition: 8,263 lbs. above deck, 650 lbs. below
Elevation -15 / +80 degrees
Elevation Rate 80 to 85 degrees per second
Train 360 degrees
Train Rate 90 degrees per second
Gun recoil N/A

The original USN version differed from the export version in that it did not penetrate the deck while the export version has below-deck magazines.

The cab in the export version is climate controlled.


Data from:

  • "The Naval Institute Guide to World Naval Weapon Systems 1991/92," Update 1994" and "US Naval Weapons" all by Norman Friedman