The Multi-Purpose Attack Crafts (MPACs) are some of the Philippine Navy’s (PhN) newest ships, and were first built by the Taiwanese company “Lung Teh Shipbuilding” and then by the Philippine company “Propmech Corporation”. The MPAC is a type of “Fast Assault Craft” that can reach speeds of up to 40-45 knots, carry 16 fully equipped soldiers (along with 2 officers and 3 crewmembers), and then land the soldiers on the beach by virtue of its shallow draft and water jet propulsion system. It has an aluminum hull and a range of around 560km.
The first 3 Lung Teh built ships are considered as the Mk1 versions delivered in 2009, while the next 3 Propmech built boats designated as the Mk2 versions were delivered in 2012. The Mk2 was redesigned as per the lessons learned from operating the Mk1 ships, and the most obvious difference between the two is the design of the Pilot House and placement of Machine Guns. Another 3 MPACs are on order by the PhN, and these will likely be designated as Mk3s.
These ships were built to carry troops quickly to the shore, so imagine my surprise when the PhN announced that they were going to use these for “harassing” enemy ships also. Because of their small size and fast speed, perhaps the PhN wanted to use these MPACs the same way the Iranian Navy uses small, fast boats (also known as “Swarm Boats”) against bigger ships as part of their Assymetric Naval Warfare doctrine.
Iran developed the use of these Swarm Boats based on lessons they learned in encounters with the United States, particularly in 1988 when the Iranian Navy suffered heavy losses in a series of naval battles against the US Navy. Despite the losses, the skirmishes did confirm the vulnerability of large ships to missile attacks, and the efficiency of the use of small and fast boats in combat, and since then heavily-armed fast attack crafts have been a major part of the Iranian Navy.
Writing about these MPACs turned out to be a bit challenging mainly because some information about them are missing. For example, the press releases never really discussed the displacement weights of the boat, its not even on the Lung Teh or Propmech websites, which is strange as this is a normally available data for boats. When I e-mailed Lung Teh for details like the empty weight, fuel capacity, maximum displacement, etc. for the MPACs, they replied that they were not at liberty to release them due to a “… non-disclosure agreement with the owner …” I never asked them back about who the “owner” is, but I assume it is the PhN.
Also, the differences between the Mk1 and Mk2 were never truly discussed in the Press Releases, but as per Lung Teh’s website, the Mk2 is faster by 5kts and longer by 2m. The lengthening of the fuselage seems to be more for improving the accommodations and seaworthiness of the vessel because they retained the same number of complement and passengers for the boat.
I am not sure why we have all these missing information, and it remains to be seen if the PhN will go out and release more complete details about these MPACs to the public.
At any rate, I am just going to assume that the MPACs have the same displacement weights and the same carrying capacity as the Swedish CB90 Fast Assault Craft upon which these MPAC were based on. There are a lot of similarities with CB90 and MPAC, ranging from the overall lines of the ship to the capacity and speed, hence whatever weapons the CB90 can carry, the MPAC will likely be able to do so also.
The PhN was not specific on how they are going to “transform” these MPACs to harass enemy ships, but there are two ways they could go about this: First is to up-arm the current Mk1, Mk2 and Mk3 boats while still retaining their troop-carrying capability; Second is for the PhN to build a separate, new class of boat based on the MPAC but designed specifically only to carry anti-ship weapons. It is likely the PhN will do only the first choice, but perhaps they will do the second choice also, who knows. The redesigned MPAC is more interesting, but this initial blog will be dealing with the up-armed MPACs only.
Looking at the CB90, its Swedish manufacturer “Dockstavarvet” does mention Hellfire missiles as an option for arming the CB90, so it seems that Hellfire missiles and SIMILAR missiles of its weight class and size are about the heaviest weapons that can be added into the MPACs while still being able to carry troops. An AMOS Twin Mortar system is also an option, but this seems to indicate doing away with the troops altogether and turning the craft into a dedicated Mortar Platform. Installing heavier weapons might have issues with other factors like SPACE and the BALANCE of the ship, which could in turn seriously affect the ship’s performance and seaworthiness.
The AGM-114 Hellfire is a good missile, but one problem I see with it is its Semi-Active Laser Homing (SALH) guidance system which requires laser “illumination” of the target until the moment of impact. If the launching ship does the illumination, its ability to make evasive maneuvers will be limited and it won’t be able to disengage quickly from the attack. A version of the Hellfire, the AGM-114L Longbow Hellfire does use millimeter-wave guidance and is a fire-and-forget weapon, but then we come to the next problem, which is the range of these missiles at only 9km. The closer the MPAC is to the enemy, the more vulnerable it is to enemy fire, hence it is ideal to have weapons with as long a range as possible.
There is another option in the Spike N-LOS missile which has a fire-and-forget-with-datalink-update guidance system and a much longer range of 25km, but it does have issues of its own also in that the manufacturer, Rafael, refuses to publish its speed, and the assumed speed of the missile is only around 175m/s or 630kph, which is slow for a missile, indicating it will have to be fired at a closer range than its maximum range to ensure a successful interception of a moving target.
For example, the time-of-flight of an N-LOS at maximum range is 2 minutes and 23 seconds, and with that time a ship traveling at 30knots would’ve moved more than 2km already, hence the N-LOS should be launched closer at 22km instead of 25km. As for its warhead, again Rafael refuses to publish it and the assumed value is only 6kg, and even that data could be wrong with the actual value even lower.
‘Impact Energy Equivalent’
One question now would be how much damage missiles like the Spike N-LOS do to enemy ships? That is not an easy question to answer, and one way to get an insight into this is to use what I call the IMPACT ENERGY EQUIVALENT (IEE), which means determining the energy of a weapon upon impact by calculating and then combining both its KINETIC ENERGY* and TNT EQUIVALENT*. The resulting value can then be used to compare the weapons with each other.
In the matrix below I have listed down a couple of weapons and their computed IEEs, which I then compare to an Oto Melara 76mm High Explosive (HE) cannon round (used by the standard naval gun nowadays for most ships) and also a 155mm Howitzer round as fired from an M114 (one of the Howitzers used by our Philippine Army). Sources taken from the following:.
As can be seen from the matrix, the IEE of the Spike N-LOS may not be as large as that of a Delilah-GL or Penguin Missile, but each N-LOS missile is still roughly equivalent to 6 76mm cannon rounds or almost 1 M114 155mm Howitzer round. A single hit on Patrol Boats less than 100tons would probably be devastating, while a hit on ships several hundred tons in weight could be enough to incapacitate them. But for even heavier ships weighing in the thousand of tons, multiple hits would likely be needed to neutralize them.
The Spike N-LOS’ warhead weight will still need to be confirmed if it is really at least 6kg, but if so, then that would make it a viable weapon for use with the MPACs. If not, then a compromise will have to be made, like perhaps using a missile with less range like the Longbow Hellfire, or still going ahead with the N-LOS despite the less damage its warhead can do.
To increase the damage on larger ships, multiple hits would be needed from the Spike N-LOS to incapacitate them, but weight restrictions on the MPACs will limit the amount of weapons it can carry. At 71kg for each Spike N-LOS missile, an MPAC can probably carry only a maximum of two each ready at the launcher if the provision for carrying troops is to be retained.
More missiles might be carried outside of the launcher, but these will have to be added or removed as the ship moves back and forth from its Anti-Ship and troop-carrying roles, which is a bit of an inconvenience considering the weight of these missiles. Reloading would also be slow and require a lot of muscle power.
An unclassified study by the US Naval Postgraduate School concluded that against a WELL-DEFENDED ship, missiles are effective only about 45% of the time, hence with two missiles per MPAC only ONE will be expected to score a hit. Multiple MPACs then will have to be assigned against large targets in order to score multiple hits.
With its small size, high speed and high maneuverability, the MPAC is a difficult target to spot and hit, giving it a natural defense against unguided munitions. However, it will still have some vulnerabilities to other types of weapons.
Without Sonar equipment, these MPACs would be vulnerable to enemy torpedos because it won’t KNOW if it is under attack and where the direction of the attack will be coming from. However, as long as it stays a good distance from enemy ships and uses hit and run tactics, it will be well beyond the practical reach of most Torpedoes. The MPACs can also always run to shallow waters as a precautionary measure where Torpedoes will have a harder time going after it.
The bigger problem would be enemy missiles as the Gulf War highlighted the vulnerability of these small boats to missile attacks. During that war in a battle around the Bubiyan Island in Iraq, Sea Lynx Helicopters armed with Sea Skua missiles destroyed 7 Fast Attack Crafts and Patrol Fast Boats as well as 14 other types of ships. One of the main reason for the lopsided result was because the Iraqi TNC 45 FAC and Zhuk-class Patrol Boats were only armed with manually-aimed Machine Guns and cannons for Anti-Aircraft/Missile defense, which were proven to be ineffective against the Sea Lynxes and their Anti-Ship Missiles.
It MAY also be possible to arm these MPACs with Man-Portable Air Defense Systems (MANPADS) or Very Short Range Air Defense Systems (VSHORAD) like the Stinger or Mistral launchers on manually-aimed mounts as I mentioned in a previous blog to lessen their vulnerability to missiles and thus give them better chances of survival. These systems don’t take up a lot of space or weight and thus a place could be found for them on the craft, even with the additional weapons payload.
The Iranian Navy Naval Warfare doctrine for the use of fast boats calls for a tactic called “Dispersed Swarming“. It meant the use the heavily armed boats to be dispersed into different locations around a target, hiding behind any cover that they can find. They are then to coordinate their attacks on the same target at the same time, closing in on the target at high speed. Depending on the range of their weapons, they are then to launch these at as standoff a distance as possible. Ideally the weapons should have a guidance system that allows the boats to disengage and turn away quickly after launch.
Since the attack will be coming from different directions, this will spread out the defenses of the target giving it little time to counter MOST of the attacks. Here is an illustration of a similar attack from a document called “The Threat of the Guided Missile Patrol Boat“:
Multiple MPACs armed with at least 2 Spike N-LOS (or similar missiles) each launched from stand-off ranges of around 20km and using “Dispersed Swarming” tactics can do good damage on even larger ships, making the idea of using them to harass enemy ships feasible. However, due to their vulnerability to missiles launched from enemy ships or aircraft, target type selection will be crucial for them to have a good chance of survivability. Less-defended, non-missile armed ships like Coast Guard ships would be a prime and ideal targets for these up-armed MPACs.
Against better-defended, missile-armed ships, I think a better, redesigned MPAC carrying heavier, more powerful weapons and with better defensive capabilities are needed for them not only to be able to actually sink larger ships, but also be more survivable. I think a redesigned, anti-ship MPAC can be done since the basic designs of the MPACs are with the PhN already and they’ve gotten very familiar with the ships in terms of operational experience and making redesigns for the boat, so the potential is there.
In parting, here is a video from Propmech Corp. showcasing the speed and maneuverability of the MPAC Mk1:
^ MPACs to be transformed into ‘harassment force’, http://balita.ph/2014/02/08/mpacs-to-be-transformed-into-harassment-force/
^ Iran’s Doctrine of Asymmetric Naval Warfare, http://www.washingtoninstitute.org/policy-analysis/view/irans-doctrine-of-asymmetric-naval-warfare
^ Specification – CB 90 H, http://www.dockstavarvet.se/Products/Combat_patrol_boats/CB_90_H/Specification.aspx
^ AGM-114L Longbow Hellfire, http://www.designation-systems.net/dusrm/m-114.html
^ Spike N-LOS Brochure, http://www.rafael.co.il/marketing/SIP_STORAGE/FILES/6/1026.pdf
^ Gil / Spike / NT-Dandy, http://www.globalsecurity.org/military/world/israel/spike.htm
^ M114 155 mm howitzer, https://en.wikipedia.org/wiki/M114_155_mm_howitzer
^ MANPADS as CIWS for the Philippine Navy, https://rhk111smilitaryandarmspage.wordpress.com/2013/09/01/manpads-as-ciws-for-the-philippine-navy/
^ The Threat of the Guided Missile Patrol Boat, http://www.foia.cia.gov/sites/default/files/document_conversions/89801/DOC_0000886761.pdf
-> KINETIC ENERGY = is the energy which a body possesses due to its motion. Formula used is (Mass times Velocity-squared) divided by two. https://en.wikipedia.org/wiki/Kinetic_energy
-> TNT EQUIVALENT = is a method of quantifying the energy released in explosions. Formula used is 1kg of explosives (in the warhead) is equal to 4,184kJ. https://en.wikipedia.org/wiki/TNT_equivalent