OTO – Melara 76 mm
One of the most popular naval guns
Primary Function: Single barrel,
lightweight, water-cooled, rapid
fire, remote controlled, dual
purpose automatic enclosed
Contractor: Designed by OTO
Range: 10 nautical miles (11.5
statue miles, 18.4 km).
Type Fire: 80 rounds per minute
Caliber: 76 mm (3 inch).
Guidance System: MK 92 Fire
One of the most popular naval guns ever produced, with OTO-Melara reporting
that about 1,000 Compact and SR guns were in service in 51 navies around the
world as of December 2002. This weapon is produced under license in
Australia, India, Japan, Spain and USA. It is manufactured in the United States
by United Defense (now part of BAE Systems), in Japan by Japan Steel Works
and in Spain by FABA (formerly IZAR, formerly Bazán). Under USN
nomenclature, the Compact is designated as the Mark 75. USN ships use the
Mark 92 FCS which is the USN's version of the Signall M20 series FCS. The
Naval Systems Division (NSD) of FMC Corporation and General Electric Co.
(Ordnance Systems Division) were both licensed by OTO-Melara and competed
for the right to manufacture the Mark 75 in the United States. In 1975, FMC/NSD
(now part of United Defense) won the competition and the first gun mount
produced in the United States was delivered in August 1978. Since 1981 all
Mark 75 orders for the USN were competed for by FMC/NSD and OTO-Melara.
The Compact was developed from the earlier 76 mm/62 M.M.I. mounting and
uses a two-piece water-cooled barrel with a replaceable liner. The gun is fitted
with a small-hole muzzle brake and fume extractor. The shield is made of
Sketch of Compact Mounting
The unique double plume of smoke forms as a result of the muzzle brake
that redirects some of the propulsion gasses back towards the gun
The double plume of smoke forms
Rear of 76 mm (3") gun
Loading a practice round
The "Super Rapid" (SR) is an improved, faster-firing version
designed specifically for anti-ship missile defense. Accuracy
was improved compared to the Compact, partly by reducing the
weight of the moving parts. OTO-Melara claims that these
changes have reduced the standard deviation values to less
than 0.3 milrads (0.017 degrees) at 1,000 m (1,100 yards) per
burst of 10 rounds when fired at the maximum ROF.
The gun shield for the SR is a rounded design similar to that for
the Compact. However, this similarity is only skin-deep as the
SR mounting has been strengthened in order to resist
overpressures up to 14 psi (1.0 kg/cm2) vs. a 7 psi (0.5 kg/cm2)
rating for the Compact mounting. As an option, both the
Compact and the SR are available with a boxier-looking
reduced radar cross section (RCS) gun shield and one of these
was used to arm the French-built Saudi Arabian frigate Makkah.
To achieve the higher rates of fire for the SR, OTO-Melara modified the ordnance itself as
well as the ammunition feed and fuzing. As a result, existing Compact mountings cannot
be converted to the SR standard, but a retrofit kit is available that does increase the ROF
for the older weapon. The magazine for the SR is independent of the turret, which means
that the feed can be interrupted to insert different kinds of ammunition, making the gun
more flexible against multiple targets.
The Italian Navy considers the SR to be an effective anti-missile weapon and new ships are
being built with this weapon in place of the twin "Fast 40" used on earlier ships in that
role. OTO-Melara estimates that, combined with the Dardo FCS, the SR can begin
engaging attacking missiles at about 6,600 yards (6,000 m), with the first rounds arriving on
target at 6,000 yards (5,500 m). With these ranges, a single gun can deal with up to four
subsonic sea-skimmer missiles, arriving simultaneously on courses 90 degrees apart,
before any reaches 1,100 yards (1,000 m).
As of this time (March 2006), the USN has no plans to use the SR version. Existing ships
will continue to use the Compact and newer ships are being fitted with the 57 mm Mark
OTO-Melara is now offering the DAVIDE anti-missile system for both new installations and
as a retro-fit kit to existing mountings. This system is designed to allow these guns to act
as an inner-defense against sea-skimming or diving supersonic and subsonic
missiles. The system will be used in conjunction with the steerable DART anti-missile
projectile and provides a continuous data stream to all projectiles in flight.
Actual bore diameter of all guns is 76.2 mm (3.00").