Knowing that a ship will last decades into an uncertain future, when you consider how a ship should be armed.
- You want at least two weapons capable of engaging each type of threat for redundancy.
- You want the weapons separated so that one hit will not disable all your weapons.
- You want to be able to engage more than one target at a time.
- You want 360 degree coverage, particularly against air and swarming surface threats.
- In addition to self defense, you may want to be able to hit targets on shore. (The Coast Guard did a lot of that in Vietnam.)
- It helps both training and logistics if the weapons are versitile enoungh that we can minimize the number of weapon types required. Ideally you want one type of weapon that can do it all.
A recent report by Naval News, Dutch LPD Karel Doorman To Receive 76mm Gun And RAM Upgrade, brought to my attention a new mount that, may allow two mounts to some degree meet all these potentially contradictory requirements.
The 76mm/62 gun may be the most produced medium caliber gun since the 5″/38 of WWII fame, with perhaps more users than any naval gun in history. The Coast Guard still has this gun, the 76mm Mk75, mounted on the Bear class WMECs. Since then, a different, much improved “Super Rapid” (SR) mount has been developed specifically for anti-ship cruise missile (ASCM) defense. In fact, it is designed to deal with the simultaneous arrival of multiple ASCMs.
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).
The Deck Mounting Advantage
Topside space on many ships is at a premium. Sensors, ECM, comms, and weapons compete for space. A gun normally enjoys pride of place on the bow, but it is more difficult to site weapons on the stern, particularly if they require ammunition handling space under the weapon.
This new mount should retain the capabilities of the SR mount (aside from fewer ready service rounds–76, almost as many as we had on the Mk75, but with the advantage of dual selectable feed) and adds the advantage that it does not require an ammunition handling space below the mount. A clever repackaging of the ubiquitous former Oto-Melara 76 mm gun looks looks like it could be the answer to a number of difficult weapon siting questions This means that it can be mounted in areas where the previous SR mount could not have been mounted, such as on the roof of helicopter hangars or on the fantail where steering gear is directly below (like where the Phalanx was located on the FRAMed 378s).
Frequently, the top of the hangar is to best location, but the space under the roof is already taken up. Weapons like the 25 mm Mk38, the 20 mm Phalanx, or the SeaRAM missle systems can usually find space aft, frequently on top of the hangar, because they don’t require deck penetration, but they do not have the versatility of the 76mm.
That might not matter much on more powerful warships that have a range of different weapons to address different threats, but for ships with a limited number of weapons, it can be critical.
Looking at the US Navy weapons that are typically mounted on top of the hangar because they don’t require below deck ammunition handling space:
The 20mm Phalanx is capable against ASCMs but it was designed to stop “leakers,” as a last ditch back up to more capable systems. It was never intended as a complete, stand alone ASCM defense systtem. If multiple ASCMs arrive simultaneously, it could probably successfully engage only one, or at most two. It does have limited short range counter drone and counter-swarm capability, but its projectile is a non explosive high velocity .50 caliber, so its effect on any but the smallest surface vessel is likely to be very limited and only then at very short range (1625 yard effective). Quoting from the link in this paragraph,
In recent years, the Vulcan 20 mm gun that is the heart of this weapon has increasingly been seen as not being effective enough against modern missile threats. However, the British Royal Navy did select Phalanx for their new Daring class Type 45 destroyers.
Phalanx is somewhat notorious for having maintenance problems, with the Navy’s Material Readiness Database for fiscal years 1997 through 1999 noting that Phalanx Block 1B (all mods) had an availability rate of between 72 and 81% for this time period.
The RIM-116 Rolling Airframe Missile (RAM and SeaRAM) is probably the best short range counter to anti-ship cruise missile (ASCM) in the USN inventory. I can understand why the Dutch chose it for the Karel Doorman upgrade. It has been modified to incorporate an anti-Helicopter, Aircraft, and Surface (“HAS”) capability. Range is reportedly 10,000 meters, about 11,000 yards, and it has a decent sized warhead, 11.3 kg (24.9 lb). That is far more than the range of the either the Mk38 or the Phalanx.
Each of these is designed for a particular threat. RAM is by far the most versatile but even it cannot match range and capabilities of the 76mm with its numerous ammunition alternatives.
Sophisticated ammunition makes the 76mm particularly versatile.
Programable Fuze: Like the 57mm Mk110, the 76mm can use a programable fuze, the 3A-Plus programmable multi-role fuze. It is described as having several modes including a time mode for air burst and a number of proximity modes: gated proximity, anti-missile proximity, conventional air defence proximity and anti-surface proximity. The fuzing includes a digital signal processor which rejects ground/sea clutter and so is claimed to be capable of detecting a missile flying as low as two meters above sea level while being able to recognise a target at a 10-meter stand-off.
Guided munitions are being developed for the 57mm Mk 110 (ALaMO and MAD-FIRES). These technologies could also be applied to the larger 76mm round, but a capability that appears similar to MAD-FIRES has been available with the 76mm for about a decade, with the advantage that it includes a proximity fuze. Additionally, reportedly, extended range rounds that may be guided against both fixed and moving targets are or soon will be available for the 76mm.
DART (Driven Ammunition Reduced Time of Flight):
European Defense Review On-Line reports,
“…the Super Rapido is offered in the Strales (or Davide as identified by Italian Navy) configuration based on the DART (Driven Ammunition with Reduced Time of Flight) guided ammunition and a Ka-band guidance radar antenna required to generate the ammunition guidance beam installed on the gun mount. The sub-caliber DART projectiles demonstrated an effective range up to 8 km (in comparison with a 4.5 km requirement) and a 1,200 m/s initial velocity allowing to cover 5 km in 5 seconds. These performances together with the high maneuverability of the DART round allowed the system to demonstrate its effectiveness against present and future ASCM targets, at a fraction of the cost of a missile engagement but with equivalent performances, Leonardo claims.”
Quoting from Wikipedia:
The DART projectile…is a guided gun projectile with radio controls and a proximity fuze for low level engagement (up to 2 meters over the sea). DART is fired at 1,200 m/s (3,900 ft/s), can reach 5 km range in only 5 seconds, and can perform up to 40G manoeuvre.The DART projectile is made of two parts: the forward is free to rotate and has two small canard wings for flight control. The aft part has the 2.5 kg warhead (with tungsten cubes and the 3A millimetric wave new fuze), six fixed wings and the radio receivers.
The guidance system is Command Line of Sight (CLOS). It uses a TX antenna installed on gun. The radio-command for them is provided on a broadcast data-link (Ka Band).
The first lot of DART 76mm guided ammunition, produced by OTO Melara, was successfully tested at the end of March, 2014. The firing trials were conducted on board one of the Italian Navy’s ships equipped with Strales 76mm SR and Selex NA25 fire control system. The first firing trials of the DART ammunition bought by Colombia in 2012 were successfully conducted in the Caribbean Sea on 29 August from the 76/62 Strales inner-layer defence system fitted to its modernised FS 1500 Padilla-class frigates.
Above is a video of the DART validation tests, first against a low level, but essentially stationary targert to test the fuzing against a target in sea clutter and then against a moving target, in this case a Banshee target drone. I believe the antennae seen attached above the gun barrel were part of the test rig, as these are not normally present on the gun mounts.
I see the possibility that there may be a confrontation between Offshore Patrol Vessels (OPV) in the South China Sea or East China Sea in which a China Coast Guard (CCG) vessel fires warning shots and directs the OPV of another Asian nation (I will call AN) to depart a disputed area. The AN OPV stands it ground and refuses to leave. The CCG OPV having a longer ranged weapon (up to 76mm currently), remains outside the range of the AN OPV and fires a few rounds for effect in an attempt to drive the AN OPV away. Whether the CCG OPV scores any hits or not, the AN OPV now has three choice, none good, stay and perhaps take additional damage, run away, or attempt to close the CCG OPV to get in range for a fight they will probably lose.
In 2020 the Chinese government made very public statements that they had authorized the CCG to use deadly force.
In 2021 Russia claimed to have fired warning shots in driving a Royal Navy Destroyer from waters of Crimea. The claim was untrue, but for many audiances, the claim probably went unchallenged.
Range matters, in the scenario above, if the AN OPV had a weapon of equal or greater range than that of the CCG OPV, the CCG OPV would probably never have fired to hit, because it could not have done so with impunitity. Reportedly, 76mm Volcano rounds that will outrange conventional rounds from Chinese and Russia guns, not just 76mm but also 100mm (3.9″) and 130mm (5.1″) and reach any target within the visual and radar horizon (to over 40,000 meters)
The Vulcano family will actually include at least three different types of 11 lbs. (5 kg), extended range, sub-caliber discarding sabot projectiles.
- Unguided Balistic Extended Range (BER) (range over 30 km/32,808 yards)
- Guided Long Range (GLR) (range over 40 km/43,744 yards)
- Guided Long Range with InfraRed Terminal Homing (GLR/IR)(range 40 km/43,744 yards)
- a Guided Long Range with Semi-Active Laser (GLR/SAL) is in development
The more recent development is the VULCANO 76 ammunition system. Basically, it is a scaled down version of the 127–155 mm Vulcano family of extended-range projectiles developed by Oto Melara; guided by Inertial Navigation System and Global Positioning Systems, it is capable of hitting targets twice the distance of normal 76 mm gun ammunition. GPS-IMU guidance and IR or SAL (Semi-Active Laser-Chuck) Terminal sensor. The Vulcano 76 GLR ammunition is expected to complete the development, test and qualification process by late 2022 with the delivery of production rounds to customers from 2023–24 onwards.
The Unguided Balistic Extended Range (BER) Vulcano round may already be operational. It would certainly be the easiest to develop. This high velocity sub-caliber discarding sabot round is usable for anti-air, anti-surface, or for Naval Gun Fire Support. At 5 kg (11 pounds) it is still about twice the weight of a 57mm Mk110 projectile. It has a multifunctional Fuze that provides options for altimetric, proximity, time and air burst, or impact and delayed impact.
Considering the Coast Guard’s implicit requirement to be able to forcibly stop even relatively large merchant ships, the combination of high velocity, semi-armor piercing, and delayed impact fuzing suggest that a BER projectile might have a better chance of penetrating the hull and delaying detonation until the projectile impacts the engine, compared to the other alternatives.
Guided Long Range (GLR):
These projectiles take the form of the unguided Ballistic Extended Range (BER) round and add GPS and inertial guidance to allow precision attack on fixed targets. The control surfaces allow a glide phase that extends the range another 10,000 meters to beyond 40,000 meter or about 22 nautical miles.
Guide Long Range with InfraRed Terminal Homing (GLR/IR):
These projectiles add a infrared terminal homing to the guided long range round so that it can target moving targets on land or water that have an infrared signature. The guidance system defines where the terminal homer will look for a target. It might be possible to defeat this round using IR decoys or obsurants (smoke).
Guided Long Range with Semi-Active Laser Homing (GLR/SAL):
Like the GLR/IR round this uses the form and function of the GLR round but instead of using IR homing, it uses semi-active laser homing, meaning some one or some thing has to illuminate the target with a laser designator. For shore bombardment the laser designator might be in the hands of a soldier on the ground. For targets afloat and ashore the laser designation might be done by an unmanned system.
For a Coast Guard cutter trying to forcibly stop a vessel, the cutter might well use a laser designator to target a particular part of the target vessel.
If you are going to put only two gun weapon systems on a ship, be it a cutter, corvette, or a large auxiliary, two of these might be a very good choice if they perform as advertised. Range with volcano ammunition is outstanding. The range of ammunition choices make these systems effective against a wide range of threats from swarming small boats, to surface ships, to UAS, to anti-ship cruise missiles. It is essentially one weapon that can do it all, atleast within the visual and radar horizon and in some cases a bit beyond.
Seems a pair of these would be a nice replacement for the two 25mm MK38s that appear to be the planned armament for the the Polar Security Cutter. Would love to see a pair of these replace the 57mm Mk 110 and 25mm Mk38 or Phalanx on our new large cutters. Replacing the Mk38 or Phalanx with SeaRAM seems more probable, but still unlikely, unless things get a lot more tense.