Modern,
miniaturized guidance technology is making possible to turn cannon shells into
high-accuracy effectors, with a great range and a cost much inferior to that of
missiles. Missiles have never entirely replaced the naval gun because of their
cost, and because they have significant difficulties in effectively engage
targets at very short range. In addition, you can’t really fire warning shots
with missiles. On the other hand, naval gunfire support was seen as a dying
specialty until not so long ago. It was indeed the experience in Libya, with
several thousand rounds expended against targets ashore, that really revived
interest for naval guns.
It is fair to
say that we are very possibly entering a new golden age for naval gunnery,
thanks to the long-range, precision guided ammunition which is about to attain
full technical maturity and enter service in the first few navies. It is
a revolution in which Italy, though Oto Melara, has a big say. And it is a
revolution that involves the Royal Navy, which plans to buy a new medium
caliber gun system (including guided, long range ammunition), rolling it in
service as part of the Type 26 Global Combat Ship package.
The Oto Melara
127/64 “Lightweight” gun and the BAE Systems / United Defense MK45 Mod 4 127/62
are the two contenders for the contract, which would likely expand, later on,
to include a retrofit to the Type 45 destroyers as well, to enable the RN to
keep its medium caliber gun logistics focused on one single type, as the old
MK8 bows out of service.
Oto Melara is
a key player in the new naval gunfire revolution as it produces those that, as
of now, are the most innovative and advanced products in the sector: the 127/64
gun, the lighter 76/62 Strales, and the related guided ammunition, VULCANO and
DART.
BAE systems
replies with the ambitious 155mm Long Range Land Attack Projectile (LRLAP),
developed specifically for the Advanced Gun System (AGS) mounted on the sole
three ships of the DDG1000 Zumwalt class of the US Navy. More significantly,
BAE systems has been recently working to validate a more exportable product
which, like Italy’s VULCANO, is compatible with normal 127mm naval guns and
155mm land howitzers: this new ammunition is the Standard Guided Projectile
(SGP) and it meant to fill the capability left by the cancellation of the ERGM
(Extended Range Guided Munition) program.
The Oto Melara
line
The 127/64
Lightweight and VULCANO ammunition
The 127/64
Lightweight is the most modern medium caliber gun in the world. It is being
installed on the Italian FREMM General Purpose frigates and it has also been
ordered by Germany for installation on the new F125 frigates.
The
Lightweight is also being jointly offered by Oto Melara and Babcock for
installation on the british Type 26 frigate.
The
Lightweight gun system is in production since 2010 and has been first installed
on the Italian FREMM-class frigate Carlo Bergamini. More
than a simple medium caliber gun, the LW is a system which comprises the gun
tower itself, the Automated Ammunition Handling System (AAHS), the VULCANO
ammunition family and the Naval Fire Control System.
The 127/64 is
the latest evolution of the older 127/54 COMPATTO gun which Oto Melara sold to
several countries all around the world (Italy, Japan, South Korea, Argentina,
Peru, Niger, Venezuela). The extent of the evolution is such, however, that it
is fair to say that the Lightweight is more or less an entirely new system.
The 127/64 gun
employs a 64 calibers barrel made of high-resistance steel alloys. It has a
water cooling system and a pepperpot muzzle brake, while the stealth shield of
the turret is realized in aluminum, lighter and cheaper than the Glass
Reinforced Plastic used in previous models. The gun tower comprises a modular
automatic feeding magazine with four rotating drums, each holding 14
ready-to-fire rounds, for a total of 56 shells.
The drums can
be reloaded while the mount is in operation, allowing for the sustainment of
extremely long bombardments. The drums can be manually reloaded by personnel
lifting the rounds in position, or they can be refilled automatically by the
highly mechanized AAHS magazine system. The auto-loader is equipped with a
system that automatically recognizes each variant of the shells in the drums,
allowing the quick selection, in any moment, of any kind of ammunition
available. The ammunition flow is also reversible, so each round can be
unloaded and exchanged right up until immediately before the firing.
The AAHS
mechanized, automated ammunition depot is a wholly modular system which can
extend over two or three decks into the ship. It is equipped with special
“moles” which can take the rounds out of the storage boxes and bring them into
the feeding drums of the gun mount. Again, the ammunition flow is reversible,
so the rounds can also be brought all the way back, with little to no direct
human intervention. On the FREMM frigates of the Italian navy, the AAHS is
installed over two decks (deck 2 and deck 3) and can hold 350 rounds in
addition to the 56 held in the feeding drums.
The 127/64 gun
system is thus able to fire 30 and up to 35 rounds per minute. The Naval Fire
Control System calculates the ballistic trajectories, programs the fuzes and,
when the GPS-guided VULCANO rounds is used, sets up the GPS data before launch.
It can be easily integrated via LAN onto any kind of Combat System, in a Plug
and Play fashion. Thanks to the NFCS, the 127/64 is also very effective in anti-air
role.
 |
| Images from the firing trials of the 127/64 of the FREMM frigate Carlo Bergamini. The first image shows the excellent capability of engagement at very short range, which can seriously ruin the day for suicide boats and similar threats. |
The
revolution, though, comes with the VULCANO family of long range projectiles.
The VULCANO, differently from LRLAP, ERGM and SGP is not a rocket-propelled
munition, but an under-calibre, rocket-shaped dart with a diameter of 90 mm.
VULCANO employs a discarding sabot to be fired out of the barrel at extremely
high speed while avoiding two of the main complexities of full-calibre
rocket-propelled rounds: increased barrel wear and tear, and difficult
deployment of the folding fins used for guidance. These problems, along with
huge cost escalation, were the factors which killed the ERGM.
VULCANO is a
steerable sub-munition with tail fins and canards. The submunition is the same
in both the naval 127mm variant and in the land 155mm variant. The difference
comes down to the sole sabot and launch charge assembly: the naval shell is an
all-up round compatible with any NATO 5’’ gun, while the army variant is
modified to employ land-specific modular launch charges.
The VULCANO
family comprises the BER (Ballistic Extended Range) variant, which is not
guided and only has fixed winglets: it uses aerodynamics and ballistic
trajectory to extend its reach to 70 km, and it is useful for a long range
bombardment in which pin-point accuracy is not needed.
The most
interesting VULCANO variants are, however, the Guided Long Range (GLR) ones.
These include:
-
GPS / Inertial Navigation System
-
GPS / INS / Semi Active Laser
-
GPS / INS / Infra-red Imaging
The GPS/INS/SAL
round variant was originally to be developed only for use from land 155mm
howitzers, but when Germany entered into the VULCANO program, they pushed to
develop it for the 127mm naval guns as well. The industrial agreement giving
the go ahead to this development was signed in the summer 2012 during
Eurosatory. Oto Melara supplies the projectile, while Germany’s Diehl supplies
the miniaturized, shock-resistant Semi-Active Laser seeker. The VULCANO is,
effectively, a tri-national program which sees Italy, Netherlands and Germany
co-funding the development.
The addition
of a SAL seeker to the GPS and inertial navigation guidance makes this variant
of the round extremely accurate. With external laser designation of the target,
it can engage with high accuracy even moving targets.
The GPS/INS
ammunition is mostly suited to use against fixed targets, whenever high
accuracy is needed to reduce the risk of collateral damage. The Circular Error
Probable for this round variant is inferior to 20 meters. This is possible
thanks to the steerable canards and fins which guide the ammunition on the
target with a near-vertical descent, which maximizes both accuracy and
lethality.
The addition
of a SAL seeker makes the VULCANO capable to engage small, fixed, moving and
relocatable targets (including vehicles and small boats) with extreme accuracy,
with a CEP reduced to a handful of meters. The Semi Active Laser seeker guides
the shell on a target illuminated by an external laser marker, which could be
“painted” on the objective by a UAV or by observers on the ground.
The IIR seeker
is instead meant primarily for anti-ship role. This variant of the round is in
fact produced only for the 127mm naval guns. Targeting enemy ships on the open
sea is a complex job, and it might be very hard, if not flat-out impossible, to
have a third party observer marking the target with a laser. The anti-ship
VULCANO is meant to be fired over the area where an enemy ship is known to be
sailing, and engage the target on its own.
The ammunition
is thus programmed to enter a descending trajectory already a few miles before
entering the target area, allowing the built-in IIR seeker to scan the surface
of the sea to detect and track the heat signature of the enemy vessel. Once the
target is located, the maneuvering round will pursue it, using its canards and
fins to steer to compensate for the enemy’s evasive maneuvers.
Much cheaper
than an anti-ship missile, the VULCANO IIR is much less deadly, taken
singularly, since its warhead is much, much smaller. However, a dart as small
and fast as a VULCANO is considerably harder to detect, track and engage with
hard-kill defences such as CIWS guns and missiles. Besides, a big number of
guided shells can be fired in very short time against the same target,
saturating its defences and inflicting deadly damage with multiple hits.
VULCANO rounds
employ a microwave fuze called 4AP (4 Action Plus) which offers detonation on
impact, proximity, time or airburst, with the possibility to program before the
launch the height over the ground at which the round will explode to pelt the
target with pre-fragmented slivers.
The advanced
fuze, the high accuracy and the modern pre-fragmented warhead compensate for
the much smaller payload carried by the sabot-discarding dart, ensuring an
adequate lethality.
In terms of
useful range, the VULCANO BER round offers a 60 km reach when fired from the
old naval 127/54 or from land howitzers in caliber 155/52 (fired by a shorter
155/39 barrel, as mounted on the British Army’s AS90, the value would be
inferior). Fired from the 127/64, the range is around 70 km.
The GPS/INS
and GPS/INS/SAL will fly 120 km if fired by a 127/64, reducing to around 100 km
when fired from the shorter barrels of the 127/54 and of the 155/52 howitzers
employed on land.
The anti-ship
ammunition has shorter legs, since it begins to descend from its ballistic
trajectory much earlier than the other variants, to enable the IIR seeker to
find the target. A warship will be engaged at around 70 to 80 km.
The BER
ammunition is readily adoptable on any NATO-standard 127mm naval gun or 155 mm
howitzer. It does not require any modification.
The guided
variants of Vulcano, instead, require the addition of the so called “V-Kit”,
the system which programs the information on the location of the target into
the guided rounds before they are fired. The modification, anyway, is minimal:
the V-Kit can be quickly installed on board the ship without requiring any
docking period. This means that it is possible to turn, with minimum
expenditure of money and time, older 127mm guns into VULCANO-capable weapons.
It is what the Italian Navy is doing, modernizing the old 127/54 COMPATTO
mounts installed on the frigate Bersagliere and
on the destroyers Luigi
Durand De La
Penne and Francesco
Mimbelli. The
Italian navy has chosen a rather important modernization, however, as it is
also introducing on these ships variants of the modular AAHS mechanized
ammunition depot. Obviously, this modification, much more challenging, does
require a period of refit.
The
Netherlands plan to adopt the same approach, modernizing the 127/54 COMPATTO
mounts on the four frigates of the De Zeven Provincien
class and also installing the AAHS magazine. Oto Melara is actively offering
this kind of modernization to all navies which employ the COMPATTO.
Germany, as
earlier said, has ordered five 127/64 gun systems, four of which will arm the
four F125 frigates, while the fifth will be used on land, for training purposes,
and has already been delivered and installed in the school of naval engineering
in Parrow.
Two more
127/64 will be delivered to Algeria in 2014 and 2015 to arm the two new MEKO
200 frigates being built by Thyssen Krupp.
Italy has
ordered two 127/64 mounts, the first of which has been installed on the
brand-new, first of the FREMM-class frigate Carlo Bergamini.
The second mount is due for delivery in 2015, to be installed on the sixth
FREMM ship. The 127/64 gun, in fact, is the main cannon for the FREMM General
Purpose variant, which also embarks an Oto Melara 76/62 for self-defence. The
ASW variant of the FREMM is instead armed with two 76/62 guns.
The Italian
navy will take delivery of four more 127/64 gun systems if the order for the
final four FREMM survives the budget cuts. The Navy is confident that all 10
the FREMM frigates will be built, but it has been suggested that, were the last
four ships to be cancelled, the ASW frigates would disembark the 76/62 gun in A
position and take the 127/64 instead.
France
currently employs a shrinking number of ancient 100 mm naval guns for naval
gunfire support, while the new FREMM vessels are armed with the Oto Melara
76/62. The experience in Libya has re-awakened the French interest for a more
capable naval guns, and the 127/64 has the eye of the DGA, however the tight
budget is preventing the launch of any acquisition program, at least for the
moment.
The land
variant of the VULCANO is due to be employed by the PZH2000 howitzers of the
Italian and German armies, and the Netherlands, which employ the same gun, also
have expressed their interest.
One future
development in the VULCANO family is the SCOUT round. This new projectile is in
Research & Development phase. It is meant to be fired first at the
beginning of a bombardment, to collect meteorological and atmospheric data
along the whole trajectory to the target.
The weather
and atmospheric conditions are decisive factors to consider during long range
artillery engagements, and with the VULCANO hitting targets at more than 100 km
away, collecting such data in a complete, reliable way is key to obtain the
maximum accuracy from the very first shot.
Meteorological
balloons are extensively used to collect the relevant data before the guns open
fire, but the balloons only collect data in the firing point area, and the
conditions can be radically different over a 100 km distance. The SCOUT
projectile would conduct measurements along all the ballistic trajectory,
self-destructing in flight at a distance from the target not to alarm it. The
data collected will be sent back to the gun mount, which, is anticipated, will
be modified to include a couple of antennas mounted in the shield, on the two
sides of the barrel. The SCOUT projectile in flight and the naval gunfire
control system would actively dialogue thanks to these antennas, and the
computer could so introduce a whole range of corrections to the firing
trajectory, dramatically improving the accuracy from the very first live round
fired. This, in itself, is a crucial aspect in enabling commanders to trust the
gun as a genuine precision strike weapon capable to surgically destroy targets
even in built-up areas, with no collateral damage caused.
The current
status of the VULCANO sees the development of the BER variant completed. The
first lots of BER rounds are in production for both the Italian navy and army,
and the live fire trials of validation and the entry in service should both be
achieved within the year. The guided variants, more complex, are completing
their development phase. In the last few weeks, the GPS/INS/SAL ammunition was
successfully employed in live firing tests from a PZH2000 howitzer, in South
Africa. This follows a series of earlier tests in the ranges at Meppen, in
Germany, where both the 155 and the 127 mm variants of the round had been fired
but, due to the constraints of the relatively small range, the maximum distance
covered had been 20 km, and the canards and fins on the rounds had been
blocked. Essentially, the tests in Germany used projectiles made incapable to
manoeuvre, and only demonstrated that the SAL seeker saw the target and
acquired it as planned.
Further firing
trials will follow, including with the 127mm variant, but the priority has been
accorded to tests from the PZH2000 since the German Army urgently needs to know
if Vulcano works: it has an important requirement for a guided artillery shell,
and the ministry of defence was oriented towards an Off the Shelf acquisition
of the proven Raytheon EXCALIBUR shell.
However, the
EXCALIBUR does not offer the accuracy and range of the VULCANO, and it is also
non readily compatible with the PZH2000’s autoloader: a problem that the
VULCANO does not have. The conclusion of the test firings will enable the german
army to order with confidence the European system, abandoning the EXCALIBUR
path. The guided variants of VULCANO should enter production next year as the
development and trials conclude.
UPDATE: demonstration firings from PZH2000 concluded in June 2014 with good results. In July 2014 the German ministry of defence decided to go ahead with a joint qualification campaign for the VULCANO system. The qualification activities will take place in 2015, with first VULCANO 127 and 155 deliveries to Germany and Italy to follow in 2016.
UPDATE: demonstration firings from PZH2000 concluded in June 2014 with good results. In July 2014 the German ministry of defence decided to go ahead with a joint qualification campaign for the VULCANO system. The qualification activities will take place in 2015, with first VULCANO 127 and 155 deliveries to Germany and Italy to follow in 2016.
The british
army might be keeping an eye on the matter, since it has a very similar
requirement for a guided artillery shell, to be fired by the AS90, with an In
Service Date planned for 2018. So far, the british army has trialed the
EXCALIBUR, and in 2010 a firing demo with a slightly modified AS90 proved that
compatibility issues had been ironed out.
The EXCALIBUR
is a virtually ready to procure solution, for the british army, but by 2018 the
VULCANO will be a mature system, in service by a few years, and it might
possibly be selected by the Royal Navy as well, introducing the alluring
prospect of joint purchases and logistical commonality, with the significant
savings that this implies.
The EXCALIBUR
is a full-calibre shell, so it carries a much larger explosive payload, but it
is less accurate (it is a GPS-only ammunition) and it only offers a range of
around 40 km, from a 39 caliber barrel such as the AS90’s one. The VULCANO
would give the Royal Artillery a much longer arm.
On the Type
26, an Oto Melara solution including 127/64, VULCANO and AAHS would ensure a
formidable firepower. The 127/64 can employ the whole range of NATO standard
ammunition, it has relevant anti-air and anti-FIAC capability and, with
VULCANO, represents a precision strike weapon with a very long arm.
The rate of
fire is also extraordinarily high. The gun now installed on the Carlo Bergamini
was extensively trialed on land: the tests included a 150-shells bombardment in
the ranges of Cottrau (near La Spezia, in Italy) during which the gun
demonstrated a 30 rounds per minute rate of fire. With the AAHS installed,
rates of up to 35 rounds per minutes are expected to be achievable.
These rates of
fire are, of course, relative to the standard and BER ammunition: the need to
program the target data into the VULCANO guided ammunitions slows down the
process somewhat, reducing the rate of fire to 25 rounds per minute. Still
better than most.
The 76/62
Strales
The other
impressive product of Oto Melara is the 76/62 gun. The 76mm gun has been around
for decades, and it has been purchased and employed by dozens of countries,
especially considering that the US Mark 75 is, in itself, a variant of the Oto
Melara product, built on license. The 76mm is, to this day, the only Oto Melara
gun to have served in the Royal Navy, as it armed the five Peacock-class
corvettes employed in Hong Kong until 1997.
The 76mm gun
is in use in 56 countries around the world.
The enormous
number of 76mm guns in service all over the world has prompted Oto Melara’s
development of new, impressive capabilities for the type. If the original
COMPATTO could fire an impressive 80 rounds per minute, the successive
evolution, the SUPER RAPIDO, increased that value to 120 (reducing to 60 rounds
per minute in a prolonged bombardment).
And now, Oto
Melara is using modern technology to turn the 76mm Super Rapido in an
impressive, all-around weapon system. The 76mm serves on several major warships
as a CIWS. This is particularly true on the Italian navy warships: the Cavour
aircraft carrier is armed with two such guns, the Andrea Doria-class
destroyers (“cousins” of the british Type 45s as they came out of the HORIZON
british-franco-italian project) carries three such guns, and they also appear
on the FREMM frigates.
With a rate of
fire of up to 120 rounds per minute, the 76/62 can put a thick wall of iron and
fire in the face of any threat aiming for the warship, but it is with the
DAVIDE model (STRALES for the export market) that the CIWS capability of the
76mm gun was really achieved.
STRALES is a
guidance kit, installed within the gun turret and comprising a radio frequency
beam antenna which is normally hidden under a sliding panel in the gun shield,
to the side of the barrel. The covering panel slides upwards to reveal the
radio frequency antenna when it is time to employ the DART (Driven Ammunition
Reduced Time of flight), a guided, sabot-discarding high speed round meant to
shot down airplanes and missiles as well as take off FIACs and suicide boats.
The DART is an hyper velocity munition capable to cover a 5 km distance in less
than five seconds, with enough energy to perform up to 40 manoeuvers and course
corrections. The projectile is composed by two parts: the forward half of the
round is free to rotate and has two canard wings which are employed to control
the flying course. The aft part contains a 2.5 kg warhead made lethal by
the pre-fragmented load of tungsten cubes meant to tear incoming missiles
apart. The fuze employed is the 3A PLUS, a programmable tri-mode device. The
tail has six fixed wings and the backwards-looking radio receivers. These, in
fact, look back to the antenna mounted in the gun shield, to keep inside the
radio frequency beam as the as they are guided in Command Line of Sight against
the incoming targets.
The system can
so engage with extremely high accuracy and greater lethality the incoming
anti-ship missiles, hitting them at much greater ranges than those achievable
with smaller, less advanced systems such as Phalanx.
 |
| A good image of the STRALES gun, with the antenna deployed and ready to guide DART rounds against their target. |
The 76mm gun,
however, is also used on many naval units as the main gun of the platform, and
not just as a CIWS. The Horizon-class destroyers of the Italian and French
navies, the French FREMM frigates and the Italian FREMM ASW frigates are the
most impressive examples of warships which do not have another, larger gun to
employ. Countless smaller naval units all over the world have a 76mm gun as
main weapon.
To enhance the
usefulness of this light gun, Oto Melara is working to develop the VULCANO
76mm, scaling down the bigger rounds. The development is progressing quickly,
and it seems that there will be a GPS/INS 76 and even a GPS/IIR 76, while the
Semi Active Laser variant is not planned, at least for now. In the 76mm
variant, the VULCANO GPS/INS round has a range of 40 km, almost twice as much
as the range of the much larger MK8 Mod 1 in service in the Royal Navy, to give
an idea. In the anti-ship role, for the reasons already explained, the range is
somewhat shorter.
The
development of the VULCANO 76mm has only been started in 2011, but the work is
progressing very quickly thanks to the experience made on the larger rounds.
Firing trials could begin already next year, and by 2015 Oto Melara believes
that it will be able to start producing the new weapon.
Both the
DAVIDE/STRALES and the VULCANO capabilities can be installed relatively easily
on existing guns. The STRALES kit has completed development and is beginning to
appear on serving warships: the Italian aircraft carrier Cavour has been the
first to have its guns modernized, and the two Italian Horizon destroyers are
following. The VULCANO capability will also be easily retrofitted on existing
gun mounts.
 |
| A drawing from the italian magazine Rivista Italiana Difesa, showing the the STRALES in its "idle" configuration (left) and ready to fire DART ammunition (right) |
The most
impressive feature, however, is the possibility to employ both STRALES and
VULCANO, from the same gun mount, giving the small 76/62 a formidable mission
flexibility. Oto Melara is working on the gun-loading system of the SUPER
RAPIDO to make it capable to employ a huge variety of rounds. This mechanical
improvement is known as Multi Feeding Ammo Selection Kit, and it builds on the
existing loader system.
The 76/62 gun
employs a drum holding 9 ready to fire rounds. The drum is constantly refilled
by two mechanical “arms” coming from the two sides, each of which holds 38
shells, for a total of 85 rounds “ready to fire”.
Currently, the
two arms are unidirectional: they only bring the shells into the drum. In this
way, each arm of the loading system can hold one different type of ammunition,
enabling the gun to select one of two types of ammunition, for each shot.
The Multi
Feeding Ammo Selection Kit intervenes on the loading arms, upgrading them to
make them capable to move in the two directions. In this way, thanks to an
upgrade to the computers, it is possible to select and load the round number X,
in the Y position along any of the two loading arms, meaning that rounds of all
types can be available simultaneously.
Thanks to the
Multi Feeding system, it is possible to modernize a SUPER RAPIDO or COMPATTO
mount, with minimum impact on weights, so that it can simultaneously employ
standard ammunition, guided DART rounds when it is necessary to shot down
incoming threats, and the whole variety of VULCANO rounds for shore bombardment
and anti-ship attacks. This makes the 76/62 an incredibly versatile and
effective weapon. A single mount of this kind gives to a ship, also very small
in size, an incredible range of combat capabilities.
The evolution
of the 76/62 has caught the interest of the US Navy, which during 2012
conducted an extensive design review of the Littoral Combat Ships which noted
that the Bofors MK110 light gun is not as effective as would be desirable. One
of the most interesting options on the table is the possible future fitting of
the 76/62, replacing the MK110.
The 76/62 is a
compact, light mount, which can be installed in small spaces and even high up
on the superstructures. On the Italian FREMM frigates, for example, one 76/62
is mounted on top of the helicopters hangar. It would be very easy to fit the
76/62 on the Lockheed Martin/Marinette Marine monohull LCS, the FREEDOM
sub-class. A bit more complex, but not impossible, would be the retrofit of the
trimaran LCS of the INDEPENDENCE sub-class, built by General Dynamics/Austal.
With the larger caliber, the longer range, and the availability of the multi
feeding system, with DART and VULCANO ammunition, the 76/62 would represent a
dramatic improvement in firepower for the LCS.
In the UK, a
76/62 gun mount could be a fantastic equipment for the future 3000-tons MCM,
Hydrographic Patrol Capability (MHPC) vessel. Although the first concepts
suggested that such ships would only be very lightly armed (just a 30 mm gun
turret, according to most), and although the Royal Navy is understandably
hesitant in adding a whole new gun, with its ammunition and logistic needs, the
range of capabilities offered by the 76mm gun is absolutely impressive, and on
its own the gun would add a lot of survivability and fightability on the new
hulls.
Finally, it is
worth to mention that the latest addition to the 76mm gun evolution tree is the
Stealth gun shield, entirely made of carbon, with foldable gun barrel and
sliding cover. This extremely stealth mount has been required by the UAE for
the new FALAJ-class corvettes.
Such
“vanishing guns” have first appeared in the US DDG1000 Zumwalt design.
 |
| A beautiful image, by Navy Recognition, showing the stealth 76/62 ordered by the UAE |
 |
| A FALAJ-class corvette shows the 76/62 mount installed and fully closed. |
BAE
hits back
The Advanced
Gun System and LRLAP
The DDG1000
Zumwalt has arguably been designed around its two “super guns”, the 155mm Advanced
Gun System (AGS). This new gun is meant to restore a powerful, long range
naval gunfire support for US Marines operations, following the loss of the
fearsome hitting power that, for decades, had come from the 406 mm guns of the
modernized Iowa-class battleships.
The 155/62 gun
is primarily meant to fire the long range, guided LRLAP munition. The gun is
wholly automatic, and the loading of the rounds completely mechanized. It
couldn’t be different, as the LRLAP, once completed with its modular launch
charge and rocket, is 2,2 meters long and weights an astonishing 104.3 kg.
The barrel is
water-cooled and folds inside the large, boxy stealth turret when not in use.
The DDG1000 has two such gun mounts, in A and B positions.
The AGS is a
massive and expensive gun system. So far, it is not planned for any warship
other than the 3 (down from an original planning assumption of 32!) DDG1000
Zumwalt super-destroyers, in themselves revolutionary but extremely expensive
ships.
 |
| A great image by NAVSEA, showing the assembly of one AGS turret |
The LRLAP guided long range munition is only employable by the AGS. Guidance is obtained by combination of GPS and an Inertial Measurement Unit for navigation. Differently from VULCANO, the LRLAP is a full calibre round, thus offering a much larger payload, meaning a heavier, more destructive warhead. The round is steered towards the target thanks to folding fins that deploy immediately after the shell leaves the barrel: recent tests have been successful, but it is fair remembering that faulty deployment of the folding winglets was one of the main problems that lead the ERGM program to its cancellation.
Proper development of these fins is a complex engineering challenge, crucial for the success of the LRLAP.
 |
| A drawing of the AGS turret, with the large ammunition magazine underneath |
The LRLAP is
capable to hit targets at a distance of 137 km, thanks to a large rocket
booster which is activated by the pressure of the firing. The LRLAP is,
differently from VULCANO, a multi-piece munition: the shell must be loaded
together with the rocket booster and the modular launch charges for the firing.
The use of
modular launch charges make possible to employ the Multiple Rounds,
Simultaneous Impact (MRSI) attack method, in which elevation and launch charge
values are adjusted for each round fired, so that up to six shells will hit the
target simultaneously (within 2 seconds), in volleys.
On the other
hand, the more complex and time consuming loading process reduces the rate of
fire of the AGS to just 10 rounds per minute, which means that a DDG1000
Zumwalt, with two AGS mounts, can fire around 20 rounds in a minute, against as
many as 25 VULCANO rounds fired from a single 127/64 gun.
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| The LRLAP round, fins deployed. |
The LRLAP is
also less accurate: the rocket booster is not the best friend of high accuracy,
and the CEP is expected to routinely sit somewhere between 20 and 50 meters.
The addition of a Semi Active Laser seeker to the LRLAP is reportedly being
considered for the future to address this problem and expand the engagement
capability, but this is all yet to come.
Of course, the
combination AGS/Zumwalt makes for an impressive “bomber”: the 14.000 tons
warship carries more ammunition (600 rounds in 2 magazines) than any likely
127/64-equipped vessel, and each shell is much larger, heavier and carries a
lot more explosive. The massive gun is capable to fire them over greater
distances, as well. However, the AGS is an extremely complex, massive and
expensive solution which might never appear on platforms other than the
Zumwalt, despite BAE’s effort in marketing an AGS-Lite.
The Standard
Guided Projectile and the MK45 Mod 4
Much more
relevant is the combination MK45
Mod 4 and SGP, which has great export potential outside of the US and which
is the other contender in the race to equip the Type 26 frigate.
UPDATE: as of December 2014, MK45 Mod 4 is thought to be the winner in the race to equip Type 26, but an official announcement has yet to appear.
UPDATE: as of December 2014, MK45 Mod 4 is thought to be the winner in the race to equip Type 26, but an official announcement has yet to appear.
The MK45 Mod 4
is the latest evolution of the MK45 gun mount which for many years has been the
US Navy standard. It presents a longer (62 calibers), more resistant barrel,
strengthened mount and redesigned gun shield. It can employ all semifixed 127mm
standard ammunition and it was designed to be able to employ two-piece extended
range ammunition. Indeed, the Mod 4 upgrade was launched specifically to employ
the ERGM projectile. The EX-171 ERGM
was to be a full-calibre 127mm shell propelled with a rocket booster and with a
special, high-energy propelling charge, meant to achieve a 41 to 60 nautical
miles range. The projectile would have been guided by GPS coupled to an
Inertial Navigation System. It was proposed for development with a load of 72
EX-1 sub-munitions (a variant of the M80 Dual Purpose Improved Conventional
Munition DPICM) that would be released at an altitude of 300 meters over the
target. The DPICM sub-munitions, also employed by the MLRS rockets, include a
shaped charge and an enhanced fragmentation case, making them effective against
vehicles, materiel and personnel.
However, DPICM
was prone to frequent failures: on average, 5% of the sub-munitions would not
explode, and they would leave large areas unsafe and in need of clearance.
Worries connected to this problem lead to a change to an unitary warhead which
would deliver on a near vertical dive (+/- 10°) . ERGM was to be 61 inches
long, and would be fired with a energy of 18 MJ against 10 MJ for a normal
shell. This made the old MK45 guns incapable to employ it, and required the
development of the sturdier Mod 4 mount, with its new barrel. These
rocket-assisted munitions continue to wear down barrels faster than normal
ammunition, in any case. In addition, these two piece ammunitions (shell +
rocket), require a more complex and lengthy loading cicle, on two strokes,
which effectively halves the rate of fire, from 20 to 10 rounds per
minute.
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| Firing the MK45 Mod 4 |
ERGM never
managed to overcome its many problems, however, while unitary cost continued to
escalate. In Fiscal Year 2008 the US Navy interrupted the over 12 years of work
on the ERGM, effectively killing the program.
This has left,
until now, the MK45 Mod 4 incapable to employ a guided, long range munition.
MK45 users, effectively, could only get that kind of capability by purchasing
VULCANO from Oto Melara.
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| The ERGM program ultimately fell apart during Fiscal Year 2008, when the US Navy terminated funding for the troublesome development |
To remedy, BAE
Systems is now working on the Standard Guided Projectile - Multi Service, which can be
considered a derivative of the LRLAP, downscaled. The SGP is a 127mm shell with
GPS/INS guidance, propelled by a rocket booster and with an in-flight
retargeting capability which enables the transmission to the projectile of
updated GPS data for the target, making it possible to strike moving
objectives.1.5 meters long and 50 kg heavy at launch, SGP is quite a large beast.
BAE aims to achieve a CEP better than 10 meters for the new round, with a range of 96 - 100 km (52 to 54 nm) and a rate of fire of 10 rounds per minute when fired from a MK45 Mod 4. The CEP value increases with the distance covered by the shell: during a test earlier this year, at 36 kilometers the error was inferior to 2 meters. At maximum range, the CEP value will of course be greater.
BAE aims to achieve a CEP better than 10 meters for the new round, with a range of 96 - 100 km (52 to 54 nm) and a rate of fire of 10 rounds per minute when fired from a MK45 Mod 4. The CEP value increases with the distance covered by the shell: during a test earlier this year, at 36 kilometers the error was inferior to 2 meters. At maximum range, the CEP value will of course be greater.
The SGP is a
full-caliber 127mm round, thus offering a larger payload than the VULCANO. The SGP comes with a 16.3 kg HE warhead (unknown balance of explosive to fragmentation material, usually it is some more of the latter). The
SGP is also offered for use on land, where it fits inside a sabot to be
compatible with 155 mm howitzers. From a 155/39 howitzer (like the one fitted
on AS90) the range is around 70 km, with a rate of fire of 3 rounds per minute.
A quick
comparison
The 127/64 gun
is the most capable and modern medium naval gun in the world, at the moment. It
offers a superior rate of fire, of between 30 and 35 rounds per minute, against
20 for the MK45 Mod 4. It also has a longer barrel (64 calibers against 62),
offering increased ballistic performance, also when employing standard
ammunition.
The naval
VULCANO is a one-piece ammunition, sabot-discarding, without rocket booster. It
is simpler, more reliable and less stressing on the barrel than
rocket-propelled rounds. The price to pay is a significant reduction in
payload, which means carrying a smaller warhead (Vulcano carries 2.5 kg of explosive, about the same as a 120 mm mortar round, plus an unknown but almost certainly similar weight of prefragmented tungsten material), less lethal. This can be a
problem at times and a benefit in other occasions: a smaller warhead is more
suited to high precision strikes where the risk of causing collateral damage is
high.
When
destructive power is key, the VULCANO is at a disadvantage. However, being a
single-piece, all-up round, it can be fired more than twice as fast as a
rocket-propelled round: a 127/64 can fire up to 25 VULCANO rounds in the same time
that a MK45 Mod 4 takes to fire 10 SGP shells.
Magazines of
the same sizes, in addition, will hold as many as twice the number of VULCANO
rounds than SGPs, as the SGP is a 1.5 meter ammunition (shell and rocket),
meaning that a ship equipped with VULCANO can compensate for the smaller
warhead by firing more shells. This has a cost, of course, but it somewhat balances
advantages and drawbacks.
Finally,
VULCANO is at a more advanced stage of development. It is overall more mature,
and already comes in several different and very interesting variants. The SAL
round, in particular, is likely to draw the attention of military planners. The
IIR round is also promising, if less immediately interesting: engaging a
warship with gun rounds instead of with missiles can be, in some cases, more
effective. And in pretty much all cases, less expensive.
The SGP promises to eventually come with a SAL seeker itself, and even a moving target capability, but this has yet to come into play, with VULCANO ahead, at the moment.
The SGP promises to eventually come with a SAL seeker itself, and even a moving target capability, but this has yet to come into play, with VULCANO ahead, at the moment.
What appears
certain, is that the rapid development of such capable artillery rounds,
offering range, lethality and accuracy, will open the doors for a new golden
age for gunnery. Missiles haven’t won the day.
