Designing a Better Anti-Ship MPAC?

[caption id="attachment_3981" align="alignnone" width="800"] The Iranian Navy's Zolfaghar variant of the IPS-16a Peykaap II Fast Attack Craft. Photo courtesy of Vahid Reza Alaei thru Borna News Agency.[/caption]

I initially wrote this blog a couple of months ago, but eventually cancelled it. The reason for the cancellation was because I realized that the “Swarm Boat tactics which these missile armed Multi-Purpose Attack Crafts (MPACs) are supposed to use have NOT worked in actual combat situations so far, at least not without using SUICIDE as a weapon. During the “Yom Kippur War”, for example, Egyptian and Syrian Missile Boats used TEXTBOOK PERFECT Hit and Run Swarm Boat tactics against the Israelis, but only ended up being massacred when their missiles missed and the more heavily armed and more sophisticated Israeli Missile Boats counter-attacked.^[1]

The Sea Tigers (the Naval arm of the Tamil Tigers) have had considerable success of using Swarm Boats tactics against the Sri Lankan Navy (SLN), but only because they used suicide to go along with their Swarm Boats. Eventually the SLN did find a way to neutralize them by using SMALL, FAST BOATS of their own as part of a LAYERED DEFENSE.^[2] Now, I don’t imagine our Navy espousing the use of suicide as doctrine to offset China’s qualitative and quantitative advantage, so I thought of just forgetting about writing a blog on building a better MPAC.

But the Philippine Navy (PN) seems intent on arming its MPACs with missiles,^[3] so I thought, what the heck, it’s a FUN blog to do, might as well go ahead with it, but this time I won’t discuss too much about the tactics to use. Also, the PN has released the specifications for its proposed missile-armed Mk3 MPACs,^[4] but I am going to INITIALLY ignore those specifications and will just discuss them later one at a time slowly in the blog. For now I am just going to focus on making my OWN assumptions on how we can possibly build a better MPAC for the Anti-Ship Role.

’Radar Multi-Path Fading Issue’
One of main reasons why small, fast boats can be a threat to ships is because they are harder to detect by radar. If you noticed, radar detection ranges for ships are much SHORTER compared to aircraft, this despite the fact that ships have much larger Radar Cross Sections (RCS) in the order of thousands of m^2 compared to aircraft which only have double-digit m^2 RCS. The reason for this is a radar phenomenon called “Multi-Path Fading”.

In simplest terms, it goes something like this: Radar will have trouble detecting objects sitting close to the waterline because radar returns will get jumbled up as it will also be reflecting off the water surrounding the ship or boat, especially since the mast of the transmitting radar is also sitting relatively low in the water.^[5] [6] The closer the object to be detected is to the waterline, the harder will it be for radar to detect it, and small boats not only have the advantage of being closer to the waterline, but they also have much smaller RCS than ships, making them even more difficult to detect by radar.

’IR Suppression’
The above issue affects only Radar systems, but nowadays most modern naval ships have other sensors as well, particularly Infra-Red (IR) sensors which can detect small boats also. The next generation of IR sensors are already present in some of the newer ships, and they are called “Passive IR Staring (PIRS) systems which provides an "always on", 360 degree view around the ship. Examples of these are the Sea Spotter^[7] and Artemis^[8] PIRS. Hence, our MPAC should also have a low IR signature to evade these systems. One way to do this is by diffusing and/or cooling its Engine and Generator exhausts, thereby lowering its IR signature.

’The Zolfaghar and C-14 Examples’
The first assumption I am going to make with our Anti-Ship MPAC is that we will want it to be as SMALL as possible in order to keep the costs as low as possible also. The current MPACs are around 17 m long with a beam of 4.76 m^[9] and approximately 15-20 tons in weight (similar to the CB90 Assault Boat), so those will be our target physical characteristics for the design. Second assumption is that we would want to mount the HEAVIEST weapons as we can into the MPAC in order to maximize its offensive capability.

For this we will have to look at EXISTING examples which we can compare to, and fortunately for us such examples do exist in the form of the Iranian Navy’s “IPS-16a” or “Peykaap II” Fast Attack Crafts. These are about the same size, weight and performance as the MPAC, and the latest version, the “Zolfaghar variant” is slightly longer at approximately 20 m in length and around 20 tons in weight, although it is a little bit sleeker with a beam of only 3.75 m. The Zolfaghar is of a traditional Monohull vessel with low Freeboard (i.e., distance of the waterline to the upper deck) design and can carry 2 Nasr-1 AShMs.^[10]

An alternative design example for our MPAC would be the Chinacat C-14 which again is very similar in size, weight and performance to the MPAC, but is of a CATAMARAN design. This gives it more stability for the same given weight of the boat, enhancing its seaworthiness. Like the Zolfaghar, the C-14 can also carry 2 Nasr-1 missiles^[10]

’Anti-Ship Missile Load’
The Nasr-1 is very similar in weight, size and performance to the Norwegian PENGUIN AShM.^[11] The Penguin Mk2 Mod7N is the specific ship-launched version of the missile, and it is an EXCELLENT AShM mainly because of its 120 kg warhead which can deliver a heavyweight punch to ships even several thousand tons in weight. It uses an Imaging Infra-Red (IIR) guidance system and has a range of only around 34 km,^[12] which is a bit on the short side, but I think will be enough for our MPAC.

Two Penguin missiles with their launchers has a combined weight of 1,330 kg, which we can now use as BASELINE on how much our new MPAC can carry, at least EXTERNALLY and ON TOP of the boat, which is how the Peykaaps and C-14s carry their missiles. Two missiles might not be enough, though, as the more missiles a boat can carry, the better chances of a hit. The next lightest western AShM after the Penguin would be the Delilah SL, and at 230 kg^[13] (plus unknown launcher weight, estimated at 200 kg) I think it MAY be possible to carry twice the number of Penguin missiles.

The only issue with the Delilah is that it has a pretty light warhead, only 30 kg and it might not be enough to do significant damage to large ships thousands of tons in weight. I’m wondering if it may be possible to double or even triple the weight of the Delilah’s warhead at the expense of less range, of which it has an overabundance of anyway (250 km). A Delilah with a 90 kg warhead, 230 kg total weight and range of around 80 km I feel would be a better AShM.

’PN Missile Requirement’
The PN's missile requirements for the Mk3 MPACs are a total weight of 1,500 kg for 10 missiles, or an average weight of 150 kg per missile. Of these, 6 should be ready for launch (a total of at least 900 kg) while the other 4 are for spares.^[4] There are several issues I see with this, first is that missiles within that weight range are either no longer in production (the 110 kg Sea Skua), or will still take a long time to be put into service (the 110 kg Sea Venom which won’t be in production until 2020).^[14]

The second issue is that like the Delilah, the Sea Venom only has a 30 kg warhead, making them only mainly effective against smaller boats up to several hundred tons in weight. But with China being relatively far from the Spratly territories, they usually send larger ships that are thousands of tons in weight since they have more range and endurance enabling them to stay longer in the area, hence larger missiles with warheads similar to that of the Penguin I think would be more suited for us.

’Other Weapons?’
Aside from missiles, what other weapons against ships that we could use on the MPAC? Well, looking again at the Iranian Navy’s small attack crafts, one alternative they use is Rocket Artillery, but I won’t take that too seriously for now. Their light warheads, limited range and lack of independent guidance systems I feel won’t make them very effective as Anti-Ship weapons. Bigger rockets with Anti-Ship guidance systems are in the works, but they are still in the “development” stage which may or may not bear fruition. 

The Penguin AShM. Photo courtesy of Georgios Pazios thru Wikipedia Commons.

The Iranian Navy small boats do use TORPEDOES as Anti-Ship weapons, but due to weight limitations are only mostly limited to Light Weight Torpedoes (LWT). These torpedoes do have some punch with their 44 kg warheads being detonated under a ship’s waterline, but their disadvantage is that they are relatively slow, and coupled with their limited range they need to be fired close enough to the enemy ship in order to make a successful interception. For example, a western LWT like the Mk 54 Mako has a top speed of 45 knots (83 kph) and a range of 20 km^[15] will need to be fired from a distance of only 7 km in order to intercept a ship running away from it traveling at 30 knots (55 kph).

Any further and the LWT won't be able to make a successful interception. And yet for an MPAC to be that close to an enemy ship would make it more vulnerable to enemy fire, so for me the lack of speed and range of these LWT makes them a less effective weapon against ships.

'Self-Defence Systems'
As discussed in previous blogs, small boats like our MPACs are vulnerable to missiles and aircraft, so to address this, a combination of lightweight “Soft Kill” (i.e., decoys) and “Hard Kill” (i.e., systems that can shoot down missiles and aircraft) will have to be installed on the boat. The ELM-2222S Nav-Guard system promises a fully automated decoy system at a lightweight configuration weighing only a couple of hundred kilograms for the total system,^[16] and thus would be ideal for our redesigned MPAC.

For “Hardkill” aircraft/missile defense, the Zolfaghar and C-14 typically carry either a manually-aimed 12.7 mm Machine gun or 23 mm Cannon, but these will NOT be effective in that role. Instead, I think the MPACs will have to go for lightweight Very Short Range Air Defense (VSHORAD) missiles to have a better chance of defending itself against aircraft and missiles. A multiple launcher with at least 4 missiles ready is ideal like the Mistral Tetral, although at 600 kg not sure if this could be fitted on a modified MPAC. If not, then a lighter system will have to be used, like the Mistral Simbad with its twin launchers and 200 kg weight, or its Remote Weapons Station (RWS) version, the Mistral Simbad RC at 350 kg weight^[17] and just rely (hope?) for quick reloading of these to counter enemy missiles and aircraft.

Without sonar equipment, the MPACs will be vulnerable to Torpedoes as they won't have any warning that an attack is taking place or where the direction of the attack will be coming from, so it will have to rely on running fast (say, above 30 knots) when carrying out its mission and going to shallower waters whenever possible in order to make it harder for Torpedoes to establish a good tracking solution and make a successful intercept.

’Multi-Role Design?’
A redesigned MPAC with AShMs would be constrained to one mission only, for Anti Surface Warfare (ASuW), so it won’t be very useful unless it is attacking and trying to sink ships. But aside from periodic trainings, I don’t think our MPACs will be going on a lot of attack missions and could therefore end up with not much to do most of the time, which is probably why the PN insisted on their specifications on the MPAC Mk3 that the boat be able to carry either missiles or personnel (maximum of 23) / payload, enabling it to do other tasks also.

However, I don’t think the Peykaap or C-14 designs can be modified to be able to carry also a complement of 23 as that will entail changing its design characteristics which may affect the overall balance of the ship, and therefore its ability to carry heavier loads on top of it. Now, of course there is NOTHING out there that will keep the PN from trying to do so, but it will be figuratively going into uncharted waters if they do and will entail more risk in terms of how seaworthy the boats will be.

I think it will be SAFER for the PN to emulate existing designs, and just do minor modifications as needed. As a compromise, it may be possible for the Peykaap design (but not the C-14 with its Catamaran design) to be modified so it can carry some troops, but it won’t be able to carry a complement of 23, it will likely be a lot less than that, probably less than half that number. With a low freeboard and low draft (even lower than the MPACs), there just won’t likely be enough space to fit in a lot of troops into the Peykaap’s hull.

The PN could introduce a certain amount of MODULARITY to the design, like having the ability to have its missiles removed and replaced with either a Heavy Machine Gun (HMG) or minor Caliber Cannon on a Remote Weapons Station (RWS) mount. This way it can have a higher degree of usefulness rather than just waiting around for a conflict with China. It may even be able to do some patrols against Insurgents/Separatists/Bandits, or to do Humanitarian and Disaster Relief (HADR) operations every now and then. Doing so means it can remain true to its “Multi-Purpose” designation.

'Parting Shot'
The new MPAC as I ENVISION it will have the following characteristics:
- Weigh in at approximately 20-25 tons and 17-20 m in length;
- Will be patterned after the Zolfaghar boat in terms of design;
- Will be able to carry a maximum load of 2 Penguin AShMs or 4 Delilah GLs on external top mounts;
- Will have a lightweight decoy system;
- Will have a VSHORAD system;
- Will have reduced IR signature;
- Will be able to carry a small amount of troops and/or some payload;
- Will have a certain degree of modularity, allowing it to carry out other missions aside from just being a dedicated ASuW boat.

If the PN insist on having as small a craft carrying as powerful Anti-Ship weapons as possible, then it will have to look no further than Iran’s “Micro” Fast Attack Crafts (MFACs?) like the Zolfaghar class to emulate. These vessels are in the same weight class as the MPACs, but carry fairly large AShMs.

I think that our "improved" MPAC with it low RCS and low freeboard would be able to sneak up on enemy ships and launch their missiles, but the problem will be enemy aircraft, like if the target ship/s is/are able to launch their Helicopters, and/or accompanying ships can launch their own aircraft, then the possibility of our MPACs being detected during its egress will be higher since these Helicopters can travel faster and cover large areas. The MPAC's better defensive systems will enable it to defend itself, but only for a short period of time as it only has a limited number of SAMs and Decoys it can use.

Hence I can’t help but feel that the PN might just be better off getting bigger, heavier ships between 500-1000 tons since these can carry bigger and better missiles with longer range, and they can also carry MORE missiles, improving their so called “Combat Persistence” or their ability to stay in a fight longer simply because they have more weapons. The same can be said of their defensive capabilities: They can carry more and better decoy systems, and more and better SAMs which translates to better survivability.

These bigger and taller ships will have less "natural" stealth capability, but these can be offset by adding stealth features to them. But then the main issue then would be COST as the bigger and more sophisticated a ship, the more expensive they will be. But that’s the way it is, you get what you pay for: Pay less, less survivable and less effective. Pay more, and more survivable and more effective.

[caption id="attachment_3982" align="alignnone" width="1200"] The Iranian Navy's C-14 Chinacat Fast Attack Craft. Photo courtesy of the Global Military Review Blogspot.[/caption]

SOURCES:

[1] Missile Boat Blog,
https://web.archive.org/web/20150805101730/https://rhk111smilitaryandarmspage.wordpress.com/2014/03/11/missile-boat-naval-battle-lessons/

[2] Sri Lanka learns to counter Sea Tigers’ Swarm Tactics,
https://web.archive.org/web/20160303211127/http://www.defence.lk/news/Sri_Lanka_Navy.pdf

[3] PHL to get Frigates, Gunboats, Helicopters as Sea row tension simmers,
https://web.archive.org/web/20151020121150/http://www.gmanetwork.com/news/story/392996/news/nation/phl-to-get-frigates-gunboats-helicopters-as-sea-row-tension-simmers

[4] MPAC Mk3 Supplemental Bid Bulletin,
https://drive.google.com/file/d/0BxdlC7sVWkVIbzFUYnIwTVNJa3M/view?usp=sharing

[5] Sea Surface reflections – Multi-Path Fading,
http://www.theradarreflectorsite.org/WebManuscript/CHAPTER%203.pdf

[6] Can the other Ship see you on Radar?,
https://web.archive.org/web/20160802143744/http://www.oceannavigator.com/January-February-2009/Can-other-vessels-see-you-on-radar/

[7] Sea Spotter,
https://web.archive.org/web/20131008062913/http://www.rafael.co.il/marketing/SIP_STORAGE/FILES/9/1019.pdf

[8] Artemis,
https://web.archive.org/web/20150913041849/https://www.thalesgroup.com/sites/default/files/asset/document/artemis_a4_en_042014_ref_103a_0.pdf

[9] MPAC Mk 2,
https://web.archive.org/web/20150527075030/http://www.lts.com.tw/web/ProductOverview.jsp?productId=0e31501e06e7238ad53d6d6d2f54f253

[10] Iranian Military Capabilty 2011 – Naval Forces,
https://web.archive.org/web/20141228214842/http://thearkenstone.blogspot.com/2011/03/iranian-military-capability-2011-open.html

[11] Iranian Short Range Nasr-1 Anti-ship Cruise Missile,
https://web.archive.org/web/20140815094425/http://globalmilitaryreview.blogspot.com/2011/12/iranian-short-range-nasr-1-anti-ship.html

[12] Penguin Mk2 Mod7N,
https://web.archive.org/web/20090902211349/http://www.redstar.gr/Foto_red/Book/Penguin.pdf

[13] Delilah SL,
https://web.archive.org/web/*/http://www.imi-israel.com/vault/documents/delilah_SL.pdf

[14] Light Naval Strike: MBDA’s Sea Venom / ANL Missile,
https://web.archive.org/web/20160303214440/http://www.defenseindustrydaily.com/light-naval-strike-mbdas-fasgw-h-anl-missile-012879/

[15] Mark 54 MAKO Lightweight Torpedo,
https://web.archive.org/web/20160718080458/https://en.wikipedia.org/wiki/Mark_54_MAKO_Lightweight_Torpedo

[16] NAV-GUARD/Naval Self Protection System - ELM-2222S,
https://web.archive.org/web/20140802072348/http://www.iai.co.il/sip_storage/FILES/5/37835.pdf

[17] Mistral Simbad/Tetral,
https://web.archive.org/web/20060514143602/http://www.mbda.net/site/FO/scripts/siteFO_contenu.php?lang=EN&noeu_id=164