Showing posts with label Sylver. Show all posts
Showing posts with label Sylver. Show all posts

Sunday, November 23, 2014

Type 26 frigates: new info and some thoughts


My earlier post on the reported troubles with firming up costs for the Type 26 and with getting to contract award have been generating a healthy discussion in the comments section, and that is great. Someone has been reading in my post a sort of hostility from me against the Type 26. I deny this very firmly. My point is another: for what we know about the ship requirements (settled in May 2012 and stable since then) and MOD-endorsed design (which has been frozen in its main lines for quite a long while, now), there is nothing excessively revolutionary that should make this platform unaffordable, considering how much equipment will be carried over from the Type 23 frigates.
It is not my invention, but a fact, that the Royal Navy has deliberately shaped Type 26 as a program which builds on earlier, incremental improvements adopted on the Type 23s and then moved across, without seeking innovation at all costs. A rough figure has been suggested, putting Type 26 in the field of "80% old, and 20% new".
This does not mean that Type 26 won't deliver a step change in capability from the current Type 23s, but rather that it will deliver so using already existing technology, and indeed re-using a fair amount of equipment.
The savings obtained by re-using equipment and by sticking with proven technology and systems are to be employed, in the idea behind the programme, to ensure a decent number of hulls get built, and to ensure that those hulls come with some new and exciting capability thanks to their large size, large aviation spaces and vast "flexible" mission space and, importantly, a large vertical launch silo that will open up routes the Type 23 has simply never been able to pursue.
I very much like the general idea, and my only wish is to see it working as intended.

I'm writing this new article because i've come across some excellent material that provides some great details about the Type 26 design that has been finalized and is being costed ahead of the Main Gate. The document is a letter, dating October 2014, from the Secretary of State for defence to the house of common's defence committee. The SoF replies to a series of direct questions, and provides some excellent information.

First of all, the Flexible Mission Bay. There is no indication of its size and shape, but the SoF finally provides a confirmation that the helicopter hangar is directly connected to the Mission Bay, with a passage large enough to enable the transfer of manned and unmanned aircraft from hangar to mission bay.
Hangar size unsurprisingy at least matches that of the Type 45: the destroyer is slightly larger in beam, but the hangar is not full-width, as it has the RHIB bays on both sides. On Type 26, there are no boat bays, although it is likely that the helicopter bay will be flanked by logistic and aviation stores spaces and by the delivery end of the new mechanized Air Weapons Handling System, designed by Babcock, which is to store, retrieve and deliver the weapons for the embarked helicopter to the Weapons Preparation Area.
Apparently, the AWHS will also handle the Stingray torpedoes for the ship's launch tubes (if they will be fitted, see further down in the article).
The hangar thus can be assumed to match the Type 45's one and it might actually be larger: the SoF says it "comfortably" fits one Merlin or 2 Wildcat. Using the Mission Bay space, more aviation resources could be carried: UAVs, both fixed and rotary wing, but also additional manned helicopters. It would be possible, albeit with limitations, to embark a second Merlin in the Mission Bay, the SoF specifies.
The ability of the mission bay to communicate directly with the hangar (and thus with the flight deck) is an eminently sensible feature to have, and it is good to have the confirmation that it will be there, and with ample chances of exploiting it over the long life of the ships (at least 25 years of design life).

It is also confirmed that the Flight Deck is being sized to allow a Chinook to land and deploy the ramp to enable comfortable embarkation and disembarkation. The compatibility with Chinook, while not strictly necessary, is useful as the heavy transport helicopter could make good use of the ample Embarked Military Force contingent that can sail into a Type 26, and it could also be used to bring aboard capability modules and stores.
Moreover, the Chinook-sized deck should also, and probably mainly, be seen as a way to ensure that simultaneous UAV and manned helicopter operations can happen with suitable space available for necessary deconfliction.
These features add a huge amount of flexibility to the design.


The mission bay itself is a large open space stretching from side to side, with large doors on both sides for deploying boats, unmanned surface and subsurface vehicles, as well as to embark mission modules which can come in containers as big as 20 feet standard TEU.
The mission bay can hold up to four 12 meters boats (and probably a few containers of additional equipment in the middle of the bay, judging from images seen this far) or up to 10 modules / 20 foot containers.
This flexibility will be invaluable in adapting to future missions and in enabling the adoption of future unmanned vehicles which are almost certain to become not just the main MCM system, but also more important in ASW. Having space and infrastructure is, consequently, very desirable for warships which have to last long into the future.
The UK is actively collaborating with France to develop modular payloads for MCM operations, and such developments are happening in other nations across NATO: the UK has taken the lead, according to the letter, for a project that aims to set international standards for the module interfaces, so that foreign systems in future can be embarked and operated where necessary.
One thing which isn't yet detailed is what kind of equipment the ship will have for embarking and disembarking containers and modules: will she depend on external infrastructure, or will the slide-out gantry crane be able to lift not only boats, but also the containers? It will be interesting to see which solutions are adopted. The mission bay will require a strong deck, as reinforced as the flight deck itself. A fully loaded TEU can weight some 24 tons, so a useful payload margin of at least 240 tons is apparently requested. The mission bay estimated size, considering what it can fit, is probably not inferior to a 15 meters long, 20 wide space.


The Type 26 will have a crew of 118, and room for 72 other personnel for the aviation element, for boarding teams, pre-landing forces of the Royal Marines, or for specialists coming to operate the modular mission systems. From the SoF letter, it becomes clear that some real attention has been paid into giving the frigate excellent capability to host the Royal Marines pre-landing party.
In recent times, HMS Montrose, a Type 23 frigate, experimented with a sizeable pre-landing force of over 70 Marines in 2012: must have been a real tight fit on a Type 23, but on the Type 26 there will be space and infrastructure to do much better.

In terms of weapons fit, the letter specifies that the vessels will be fitted at build with a sizeable Flexible Strike Silo numbering 24 cells, for anti-ship, land attack and anti-submarine weapons. The letter specifies that the cells will be american MK41. This is a surprise, since earlier info suggested that since MK41 is somewhat larger than Sylver modules, only two launchers (for 16 cells in total) could be fitted: it appears it is not so, and the higher number of cells has been confirmed in the finalised design.

Confirmed are the 48 Sea Ceptor canisters as well, almost certainly in the two silos configuration seen in CGIs and models so far, so with 24 cells on the bow, ahead of the strike cells, and 24 aft of the funnel mast, amidship.
The Type 26 will have a 127mm gun, too, replacing the old MK8. I'm told that, although it has not yet been officially announced, only the MK45 Mod 4 remains in the frame, with the Oto Melara 127/64 out of the race. Jane's had reported a while ago that the MK45 had been given preferred bidder status, so it seems things are moving in that direction. The new gun will "allow" the Navy to buy into the new long-range guided ammunition being developed for the calibre, which is a NATO standard, unlike the 114 mm of the MK8.
There will also be two 30mm light guns, as expected, and the possibility to fit two Phalanx CIWS.

The list shown in the letter comes without one notable piece, however: it makes no mention of Stingray torpedo tubes, which is very surprising considering that the Type 26 is an ASW platform, and that the launcher systems could reasonably be transferred from the Type 23s.
It is an omission that causes questions to arise: it seems unlikely that there would not be such a fit on this kind of vessel, especially since vertical launch anti-submarine rockets, which are mentioned in the letter, are not in british service, and would have to be somehow procured (read: financed, as that is the issue). It is not a product line where there is much choice: the americans have the ASROC, the italians have the MILAS (which is not vertically lauched, however) and the South Koreans are producing a system of their own. Japan also has its own anti-submarine missile system. None of these is fitted with a british Stingray torpedo, obviously, although this could probably be fixed quite easily.
Not fitting the torpedo tubes would be a puzzling decision, if confirmed. The ship's tubes are admittedly more of a snap self-defence fit than anything else, considering the limited range of the lightweight torpedo fired from them means that the frigate launching them would probably already be under attack by the enemy submarine; but doing away with them entirely, besides while not having a clear path to a vertical launch solution, is questionable.
Might it be just a case of them having been "forgotten" in the letter? Can't be excluded.

The letter also has another nice little bit of a news in itself: the FASGW(L) missile, the Thales Light Multi-mission Missile, has been given the name MARTLET in british service. This hadn't been disclosed to the public before, as far as i'm aware, unlike Sea Venom which was named earlier this year.

(Secretary of State for Defence - Type 26 letter to the defence committee)




A displacement of 8000 tons? 

Type 26 is going to be a large and "dense" warship. The 6000 tons displacement quoted by BAE is pretty much certainly not the weight of a fully loaded Type 26, and indeed some recent news reports have suggested that the ship might now be an "8000 tons full load displacement vessel". I'm however not sure i can believe the 8000 tons value at this point, because it sounds excessive in relation to the specifications and the size of the vessel, but it will be an heavy ship, that's for sure. The SoF letter does not provide any helpful indication about this subject.

Type 26 is 148,5 meters long and around 20 meters in beam. Not too far from the 144,6 and 19,7 meters of the italian variant of the FREMM frigates (the french ones are slightly shorter, as the italian ships are being lenghtened post-build by some 3,5 meters adding an additional section in the stern) which have a declared displacement of 6700 tons, sometimes indicated in more than 7000. The italian navy has released some different, contradictory figures for the displacement, which consequently isn't identifiable with certainty. Even the reason for the lenghtening isn't yet fully clear: officially, the expansion was mainly due to the need to improve all-weather operations with the AW-101 Merlin helicopter and was exploited to provide additional accommodation space, 100 tons of additional fuel (bringing endurance to 6700 nautical miles against 6000 earlier) and a second RAS station. The weight increase coming from the lengtening was indicated in 250 tons.
Unofficially, there have been strong suggestions that the lenghtening has been inspired by the wish to correct weight distribution, as the italian FREMM have been given the same huge main mast of an Horizon destroyer, carrying the heavy, powerful EMPAR radar system, and this has, again reportedly, made the ship remarkably bow-heavy, with consequences on handling, particularly in rough seas.

In many ways, the italian FREMM is a good comparison to Type 26: the italian navy is taking delivery of two variants, the General Purpose and ASW. The first replaces the towed sonar of the second with a stern ramp for the deployment of a 11-meters RHIB. The other main differences are that the GP is armed with a 127 mm gun and a 76 mm gun-CIWS, while the ASW has two 76 mm guns. The GP is, for now at least, not fitted with the SLAT anti-torpedo decoy system, which is instead standard on the ASW.
Both ships carry two helicopters in two hangars: one, slightly larger than the other, can house an AW-101 Merlin, while the other is sized for the NH-90 helicopter. The frigates can employ one AW-101 and one NH-90, or two NH-90.
In fairness, i've heard comments suggesting that the AW-101 hangar is quite tight, and considered more adequate to carry a NH-90 and offer spaces for its maintenance rather than allow the actual enduring embarkation of an AW-101 Flight. The smaller hangar bay has been described as just large enough to house the NH-90, without work spaces, so it does seem more practicable to go with two NH-90s, which is by the way more likely as Italy is procuring 40 to 46 NH-90 NFH, while the AW-101s are much fewer (10 ASW, 8 amphibious assault / transport and 4 AEW) and generally meant for use on the Cavour aircraft carrier.  
Both ships employ one 11-meters RHIB and one 7-meters one, with the GP adding a second 11-meters in the stern, as already said.

It would be interesting to have an accurate displacement value, as it could provide a useful ballpark idea for what the Type 26's own displacement might be.

The italian FREMM has accommodation for at least 200 following the modifications (180 on the french FREMM), but also has a core crew considerably larger than the french variant (108 including 14 men of the helicopter flight): the GP was meant to have a crew of 131, and the ASW of 133. Use of the platform at sea has since inspired an expansion of 34 men, as well as some 23 for the aviation department.
The increase in crew size has had some impact on the vessel: currently, the space originally preserved to fit two 8-cell Sylver A70 launcher modules for strike missiles has been sacrificed to provide additional accommodation spaces.
The standard of accommodation, especially in the original rooms, is very high. The room with more bunks has only 4 beds. That's a lot of volume used in what does not appear to be a very efficient way.  

The Type 26 is aiming for a core crew of 118, with accommodation for another 72 personnel. On the Type 45, junior rates sleep 6 per room. On the Queen Elizabeth class, the 6 bunks rooms are larger, but come with two folding beds which can be used to embark 2 more personnel.
On the Type 26, which will need some pretty well optimised use of space for fitting accommodation for 190 plus a large flexible mission bay and a substantial number of VLS, the arrangement of bunks has not yet been detailed. However, back at Euronaval 2012 some reporters talked about 9-bed rooms, a bit of a sacrifice in terms of crew spaces to make everything fit.

Sensor-wise, the italian FREMM is fitted with the EMPAR, as said earlier, a system considerably larger than ARTISAN 3D: the antennas of the two systems weight 2,45 tons against 0,7 tons.

In armaments, the italian FREMM carriers two 8-cell Sylver A50 modules, with the SAAM - Extended Self Defense control system, which enables limited area defence employing not just Aster 15 but Aster 30 as wll. The limitation in area defence performance comes, effectively, from the fact that the FREMM does not support the EMPAR with a long-range radar as happens instead on the Horizon destroyers.  
Type 26 will be able to employ up to 48 CAMM / Sea Ceptor missiles, distributed in two silos. Weight-wise, despite the big difference in numbers, it is the SAAM-ESD that weights the most, since each Aster 15 in its canister weights a full 550 kg, with Aster 30 reaching the 700 kg, while each CAMM canister is in the region of the 100 kg, and being a cold-launch weapon it does not need a VLS as bulky and complex as Sylver (over 8 tons per module, but exact weight not available).
The FREMM armament is completed, in the GP case, by a 127/64 gun (34 tons with turret ammunition drums filled with 56 shells) plus 305 shells in an automated handling two-storey ammunition depot; two 25 mm guns, two triple MU-90 torpedo tubes, eight TESEO anti-ship missiles (770 kg each in their canister) and a 76mm gun on top of the hangar, weighting 7,9 tons without ammunition.

The Type 26 however will have, as of October 2014 information, 24 MK41 strike lenght cells available in addition to Sea Ceptor. Each module, bare of weapons, weights some 14,5 tons. If each cell was filled with a MK14 Mod 2 canister containing a Tomahawk missile (the heaviest, at 2,777 kg each), the weight would rise rapidly! The maximum weight of the Flexible Strike Silo, launchers plus Tomahawk canisters, could be in the region of an impressive 110,15 tons.
However, to this day there is no real indication yet of what the Royal Navy wants to fit. Tomahawk appears to be likely, but the Royal Navy also needs to replace Harpoon, and the only MK41 candidate which could be readily available by then would be the american LRASM solution. The anti-submarine "rocket", if it will be actually pursued at some point, would be another novelty.

The italian FREMM carries enough fuel for 6700 nautical miles, and enough stores for 45 days, officially. The Type 26 reportedly aims for no less than 7000 nautical miles and 60 days, so there might easily be dozens of tons of difference in the amount of fuel carried, and a significant difference in the volume and weight of stores, as well, but providing exact figures is not possible at this point.
The propulsion systems have in common the presence of a gas turbine and four diesels, but that's about it. The italian FREMM uses a 32 MW LM2500+ G4 gas turbine and 4 Isotta Fraschini VL1716 diesels and 2 Jeumont Electric motors, while the Type 26 will have a 36 MW Rolls Royce MT30 and 4 MTU V20 diesels generating 12 MW. However, the FREMM is a CODELAG ship which can run the gas turbine and the diesels at once to sustain high speed in rough sea or obtain greater max speed, thanks to a RENK 170-175 gearbox set weighting some 120 tons; while the Type 26 will be CODELOG, which means the diesels will be used to generate electric power for silent cruise speed, but will be detached when max speed is requested, leaving the sole MT30 to directly drive the two shafts.
The electric motors of the Type 26 are to be supplied by General Electric, and the gearbox by David Brown.

Overall, it is quite natural to expected a loaded Type 26 to exceed 7000 tons and the weight of the slightly smaller and less armed FREMM, but 8000 tons would seem to be an exaggeration.



Costs  

It is a good thing that the Type 26 does seek to reuse much of the expensive equipment fit (main radar, Future Local Area Air Defence System / Sea Ceptor, light guns, navigation radars and other equipment) and build on existing technology (including the shared infrastructure common combat system, which is being rolled out across the Royal Navy's surface fleet in the coming years, having already been installed on HMS Ocean, ordered for the Type 23s and mandated for the new build OPVs), because otherwise there would be no chance to meet the ambitious cost targets set for the programme.
The hull is going to be big and capable, and very dense, with such big spaces being requested for the Strike VLS, mission bay, fuel and stores. The Strike VLS fit is not new (it builds on something that is operational on hundreds of ships around the globe) in general terms but is a new entry in the Royal Navy, so will need to be acquired anew.

Ultimately, we do not know which is the current target pricetag for the Type 26. The newspapers have recently made headlines about Type 26 being a 4 billion project, but this isn't too helpful because government has notoriously indicated that there is likely to be a first contract for 8 ships, to be followed (hopefully) by 5 more later. If 4 billion applied to the first 8 hulls only, the cost per ship would 500 million pounds, rather non ambitious at all. On the other hand, 4 billion for 13 ships would likely be too little, at little more than 307 million per hull. Result maybe not beyond the realm of the possible in general terms, but looking too ambitious for british shipbuilding, which isn't really famous for being cheap.

Maybe the danes could get it done: they have very successfully built the IVER HUITFELDT class frigates, three capable air area defence warships which have cost an amazingly low 313 million USD each.
These impressive vessels, however, build their hulls on the experience of the commercial operator Maersk, a factor not to be underestimated. The design has also benefitted from previous work done to design the Absalom class, another success story.

The IVER class use a fully-diesel propulsion with 4 large MTU sets which can push the ship for 9300 nautical miles at 18 knots, but that can also thrust her to over 29 knots speed with a 120 seconds acceleration time. The base crew of 116 isn't too far from Type 26's target, nor is total accommodation available, set at 165+ men.
The IVER is a 6649 tons displacement vessel, about as large in beam as Type 26, but around 10 meters shorter.
The ships are fitted with an advanced combat system and with the excellent APAR multi-function radar used also on the german SACHSEN ships, supported by the SMART L, the long range radar which equips the Horizon and Type 45 destroyers (in the S-1850M variant). They have a 32-cells MK41 Strike Lenght silo amidship, supplemented by 24 additional cells for ESSM missiles and by space for more ESSM or for up to 16 Harpoon. They are fitted with two 76 mm guns, and a Millenium CIWS, but could soon enough swap one 76 for a MK45 MOD 4 gun. The other 76 could stay or be replaced by another Millenium.



Amazingly cheap, these ships deliver formidable value for money. The budget for all three was 940 million USD, supplemented by 209 million in re-used equipment (ESSM cell modules, Harpoon and 76 mm guns, mainly). The budget did not include the purchase of the SM-2 missiles for air area defence, so for now the MK41 is empty and only ESSM is available, and the 127 mm gun is planned but not yet purchased.
Deep in the hull, they have space reserved for a towed sonar, and further space for other equipment with a footprint equivalent to four 20 feet containers. 







It will be a big challenge for the british shipbuilding industry to keep Type 26 costs down. There is no revolutionary system being requested, but on the other hand there is admittedly quite a lot of capability being designed into a dense hull.
The amount of re-use of existing equipment migrating from the Type 23 could be a real lifesaver for the programme: the abundant carry over should represent a big "saving" of sort (money will have of course have been spent for all items, but early and separately), especially since it covers most of the big-money items of the combat equipment.

Saying how much it will cost to fit the new MK45 main gun and the MK41 silo is not easy, but thanks to an immensely useful USN document detailing the cost of new build DDG-51 destroyers by major subsystems, i've put together a ballpark estimate. Take it with prudence and salt, of course: this is a very rough method for estimating costs, but i think it is interesting enough to be included as a basis for discussion and reflection.



To provide a rough cost indication, i've scouted US Navy documents which helpfully provide a major breakdown of the cost of a DDG-51 by major subsystems and related components and activities, looking at the years 2013, 2014 and 2015. There are, as always happens in these things, some pretty large variations in price from a year to the next, but it is at least possible to get an idea. The yearly data suggests that ordering many in the same years significantly lowers the costs with economies of scale. (USN document)




The MK41 fit on a DDG-51 is a 12 launch modules affair, with a cost in the region of the 48 million dollars. 12 modules, however, are the fit of 4 Type 26s, according to the info we now have. So it might take around around 160 million USD to put 24 MK41 cells on all Type 26s. Rough estimate, of course, i want to say that again. The number of modules is lower per hull, but there are more ship sets. However, there should not be a big difference per se in terms of ship sets installation. Dropping 36 modules in three hulls or 39 in 13 hulls shouldn't be excessively different, but for the fact that they would be separate operations happening on different years. This might raise the cost, but overall i would like to think that things would even out in a reasonable way.

If it is decided that the Type 26s have to be able to successfully employ Tomahawk, they need the Tactical Tomahawk Weapon Control System fit too, and that could require up to some 16 million USD per ship (cost for a single ship set in 2014, the unitary cost drops as low as 11 million with 3 sets in 2013 and 13 million with 2 sets in 2015). 16 million for all 13 ships would add up to 208 million for the class. Again, rough estimate. All costs inclusive of technical support, engineering, initial spares etcetera. I don't know if LRASM has a comparable, separate mission planning system. Probably not, but there would be of course integration costs of its own with it having its own backend in a shape or another.

The rest of course depends on the missile, and how many All Up Rounds are purchased. The last Tomahawk contract, which included 20 submarine torpedo tube TLAM for the UK, was a firm fixed price order for 231 rounds (147 Vertical Launch rounds for US surface warships, 64 encapsuled rounds for US navy submarines with VL cells and 20 torpedo tube launch TLAM rounds for the UK) for 251,13 million dollars.


In theory, and i'll say it again in theory and in rough estimates, 24 MK41 cells + Tomahawk mission system + 231 missiles (using the 231 figure and its cost, even though the torpedo tube missile is more expensive than the VL) = 619.13 million dollars, or around 396 million pounds, at today's rates. And that's with a 231 TLAM order thrown in for good measure, that we all know isn't going to happen. Probably there would be a finite, much smaller number of missile loads purchased, and the deploying ships would stop by the Upper Harbour Ammunitioning Facility prior to deployment to take the rounds on board, since pretty much never are we going to see all 13 vessels on operations at once anyway.

All this, just to have a ballpark idea based on something. Better than speaking purely on wild speculation.
If you follow the link to the US Navy document, you'll see that it quotes Unitary Item Costs which are all much lower than the amounts i used. I did that deliberately, by looking at the total expense per ship related to the various items so to include, albeit of course in a rough way, the spares, engineering and services costs which are very much inevitable. Using the unitary cost alone would not be realistic, as the amounts resulting would be much lower than the real ones. In this other way, the cost figures should be much closer to the truth. 
This is mainly to indicate that it won't be the fitting of MK41 launchers that will break the programme's budget on its own: they fit 32 MK41 cells on the cheapest high end combat ships out there, as we saw.

As for the MK45 Mod 4, it is also of some interest to see its cost is in the region of some 25 million apiece, apparently. Again, the cost for a british purchase might be different, and it is indeed likely to be somewhat higher since for the UK it will be a totally new system, while it is business as usual for the US Navy. 



In this long piece, i've wanted to share the quality info i've found about what the design of Type 26 offers, and i've also tried to explain why i talked the way i did about the reports of cost issues and the delay in clearing Main Gate. The requirements, taken as a whole, are ambitious in several ways, and i won't deny that. But they have maintained steady over time, and they are being mitigated by a responsible approach to the programme. I hope that now the whole package can be made to work, and work well. Because one thing is certain: this programme is of vital importance to both the Navy and the british shipbuilding industry. It is in the interests of both that it goes as planned. 
If it did, it really might be a renaissance for british yards, because this ship, while not revolutionary in its subsystems, is very much (r)evolutionary in terms of what it delivers as a whole. A good product at a reasonable price: what is needed for the Navy to survive, and for export orders to return to british shipyards.


Wednesday, October 9, 2013

Vertical Launching Systems and the Type 26




Much discussion has been caused by the Type 26 model shown at DSEI 2013, as this new model showed just 16 VLS Strike Length cells instead of the 24 shown earlier at Euronaval 2012. Reportedly, the main reason behind the difference is the fact that at Euronaval the model was fitted with the European SYLVER VLS system, while the DSEI model was fitted with the American MK41.
Why the very noticeable difference? 

In this photo by Navy Recognition, the Type 26 model seen at Euronaval 2012: there are 24 SYLVER A70 cells
 
The photo from DSEI 2013, showing only 16 cells, MK41 Strike Lenght. Overlayed in red, the big question: is there under-deck space for fitting two more MK41 modules, replacing the CAMM cells? The deck area is not a problem, but space under deck might be, as CAMM cells only go around 3 meters deep, while MK41 Strike would go down over twice as much.


MK41

The MK41 vertical launch system was conceived in 1976 and first appeared on the cruiser USS Bunker Hill. The vertical launch system, conceived by FMC but produced by Martin-Marietta (now part of Lockheed Martin), was a major upgrade from the MK26 launcher, which employed a twin-arm ramp with an under-deck ammunition depot for 44 missiles. The same space occupied by a MK26 launcher, thanks to the MK41, became a 61-missiles silo, with all missiles constantly ready to be fired, against only 2 ready to fire on the arms of the MK26 ramp. 


Two graphics showing the complex MK26 twin-arm launcher that the MK41 replaced.Missiles were vertically struck down in the two conveyors, and vertically pushed up onto the launcher's two arms.
 
The MK41 comes in modules which have 8 missile cells each, arranged in two rows of four aligned on the two sides of a vertical uptake used for venting hot gas. Originally, there was also a module with just 5 missile cells, with the space of the other three occupied by a fold-down crane for at sea reloading, as we’ll see. 

 
MK41 quick overview. Also shows the two large multi-module silos on Arleigh Burke-class ships

Each module carriers its own launch sequencer, motor control panel and gas exhaust system. When a missile is fired, it exhausts downwards through the blowout bottom end of its canister; the hot gas goes down into the MK41’s plenum and then vents upwards through the uptake, which has its own hatch opening between the two rows of cells.
The plenum can withstand 7 launches from each cell, plus a restrained firing with full motor burn from any other cell. A deluge system is installed to provide flooding of missile cells to prevent warhead explosions. 

The uptake hatch between the two rows of four cells is very evident in this image, showing the launch of a Tomahawk. Notice the high pressure, high-temperature gas venting upwards from the hatch.
 
Multiple MK41 8-cell modules can be assembled together in a silo: Ticonderoga class cruisers were built with two large silos, each containing seven 8-cell modules plus, originally, a 5-cell plus crane module, giving the ship a total of 122 missile cells. 

What looks like a 5+crane MK41 module is being lowered into the silo, to join three 8-cell modules already in position. Note the density of the installation. A further four 8-cell modules will follow, to form a 61 cell large silo.
 
A 61-cell silo, completed, with a caniser being lowered towards an empty cell. Note the 3-cell wide hatch of the crane, in the second module from the bottom, to the right of the image.
On the DDG-51 Flight I and II, the MK41 modules were arranged in a silo with 29 cells on the bow (the equivalent of three cells taken up by the crane) and 61 on the stern. 

The All-Up Round missiles used in the MK41 come in sealed canisters which are used for storage, transportation, handling and, ultimately, for launch. Once a canister is struck down into a VLS cell, it becomes an integral part of the launcher system. Each canister has a common external envelope to support system launcher module interfaces, while internal mechanical and electrical components are tailored to specific missile shapes and interface requirements. In other words, to each missile, its own canister:

MK13 canisters are for Standard SM-2 series missiles;
MK14 canisters are for Tomahawk
MK15 canisters are for ASROC
MK21 canisters are for SM-3 anti-ballistic missiles
MK22 canisters are for Sea Sparrow
MK25 is the special, quad-pack canister for ESSM 

There are successive variants of the canisters. Today, the Tomahawk All-Up-Rounds come in MK14 Mod 2 canisters. Before it came the Mod 1, which had a launch security device for the control of Tomahawk employment, and by the Mod 0, which had a key-operated security device against unwanted launches, as it was meant to carry the now withdrawn nuclear-tipped Tomahawk.
The canister MK21 Mod 3, instead, is a slightly modified MK21 used with the new Standard SM-6 missile.

Canisters have a shell structure is a steel weldment with corrugated steel skins and cast steel end frames. They are fitted with a variety of vital equipment and characteristics, including: adjustable lateral restraint shoes, longitudinal shock isolators, an ablative coated steel baseplate structure, ablative blocks, deluge piping, nitrogen fill piping, cables, a code plug and a Canister Safe and Enable Switch. The Canisters also contain a telemetry antenna and monitoring connection.
The canisters are not simple boxes. They contain precious equipment, and the missile cannot do without its canister. 

Open MK41 cell hatches, showing the empty shafts. Without canisters, the MK41 is little more than a metallic frame.

An overview of the MK14 canister, employed by Tomahawk

The Tactical Lenght MK15 canister, containing the ASROC missile, and showing the MK18 canister adapter that allows the use of shorter canisters in the Strike Lenght cells

Inserting a canister down a MK41 cell

MK41 comes in different lengths, which determine the size of the canisters that can be installed and, consequently, decide which weapons can be integrated.
The canisters have a square base, with a total diameter of 25 inches. Inner diameter of the space for the missile is around 22 inches. There are three canister sizes:

-          170 inches; for self-defense weapons only (Sea Sparrow, ESSM)
-          228 inches; add SM-2 and ASROC
-          264 inches; add Tomahawk, SM-3

These canisters fit into into different length MK41 launchers, obviously. This value refers, effectively, to the heights of the modules to be installed in the ships.

-          Self Defense Launcher is 209 inches
-          Tactical launcher is 266 inches
-          Strike launcher is 303 inches

The Tactical Length canisters, however, can be and are fitted into Strike Length cells with the aid of the MK18 Canister Adapter, a steel weldment with appropriate dog-down connections that serves as a conduit for rocket motor exhaust vented to the plenum. Fitted to the bottom of the shorter canister, it allows it to fit easily down like it was a strike-length canister.   

The deck area of a 8 cell module, instead, remains the same. The short side of the launcher is 81.75 inches, while the long side is 124.63 inches. Depending on their height, empty 8-cell launcher modules weight 26.800 lbs or 29.800 lbs or 32.000 lbs for the Strike Length launcher. 

The old 5-cell plus crane MK41 module. This is no longer produced or employed, as the crane never worked as well as hoped. It remains an impressive bit of kit, though.
 
Using the crane at sea for reloading

The fold-down crane for at-sea reloading of missile cells was contained under deck in a space equivalent to just 3 missile cells, and elevated outwards during reload operations. The requirement was for the replenishment of 10 VLS cells per hour, even in Sea State 5, with the missile canisters being transferred via RAS (UNREP for the Americans) rigs.
Reloading of missile canisters at sea, however, proved always difficult at best, and the ingenious crane, albeit fascinating, was never capable to deal with the larger and heavier canisters, such as the MK14 containing the Tomahawk. The failure of the VLS replenishment at sea is summarized as follows:


The original development of the MK 41 Vertical Launch System (VLS) for cruisers and destroyers in the late 1970’s included a requirement to replenish ten VLS canisters per hour, day or night in Sea State 5 conditions. The system actually installed consisted of the STREAM rig to transfer the VLS canister to the missile ship sliding padeye; then deck handling the canister to a position where a crane could tilt up the canister over an empty cell and then strike the canister down. The crane was a commercial Swedish folding crane. Three canister cells were combined to make stowage for the crane. An elevator raised or lowered the crane. The at sea VLS Unrep technical evaluation discussed in Miller (1992) identified that the crane did not have the capacity to lift Tomahawk VLS canisters; SM-2 VLS transfer rate was three per hour and the pendulum action of the crane limited Unrep to Sea State 3 conditions. The cranes are now in layup.


Eventually, the ambitions of at sea reloading of MK41 cells were abandoned, and the DDG51 of the Flight IIA were never fitted with the crane, instead getting 32 and 64 cells silos. The cranes were at times used during Desert Storm, to aid the correct placement of missile canisters. Desert Storm, in 1991, provided the US Navy with the first experience of wartime reloading of warships fitted with MK41: the USS John Paul Jones was the first warship to receive a wartime reload of Tomahawk missiles, but did so while pierside in Mina Jebel Ali, in the United Arab Emirates.
The closest thing to an at sea wartime reloading was the transfer of shipborne missiles from support vessels to warships in the lee of Masirah, Oman. The ships were motionless in the protected waters, but not moored to the bottom, as it was felt tactically advantageous to be able to move quickly in case of enemy attack.  

Interest in at-sea reloading is not dead, and a solution might come in service in the future, since the impossibility to rearm a major warship without pulling it away from the fight and into enclosed, friendly waters is seen as a major limitation. The logistics of VLS reloading are complex, and require extensive material handling mechanical equipment, time and adequate portside or shipborne facilities. The new Upper Harbor rearming facility built by the Royal Navy at Portsmouth is a good example of structure thought specifically for the replenishment of VLS cells. 

The new, specialized rearming facility built for Royal Navy use, with the two cranes for VLS reloading.
 
During war operations abroad, having at hand such a well-equipped facility could be a real problem, as US documents have underlined for decades.

"double-ended" VLS ships such as AEGIS cruisers and destroyers can be rearmed twice as fast if two cranes are available (a frequent bone of contention at stateside weapons stations). With both cranes swinging canisters and enough forklifts and pier-side handlers to keep up with them, a motivated AEGIS crew can completely reload the ship's VLS systems in one (long) day. Note the optimum requirements, though: a pier of sufficient length and with water alongside to accommodate ships up to 563 feet long and 32+ feet in draft; cranes, forklifts, trucks, and/or flatbed rail rolling stock; and contiguous or near-contiguous cargo ports or airfields. Such a facility is precisely the kind of "logistics node" that the JFMCC will be attempting either to defend or seize early in a regional conflict. When in friendly hands, such a facility is a prime TBM target in its own right, as seen at Jubayl, Saudi Arabia, on 16 February 1991, when an Iraqi Scud impacted within yards of an ammunition pier berthing seven ships, a supply barge, and the USS Tarawa.

An at-sea rearming technique and equipment is part of US Navy ambitions to modernize Underway Replenishment (UNREP) technology, effects and methods. The following describes one of the possible approaches:


The concept for replenishing 15 VLS per hour in Sea State 5, shown in Figures 9, 10, 11 and 12 centers around a transportable VLS rearming device that is stowed and maintained on the Combat Logistics Force (CLF) ship. When the combatant ship comes alongside for at-sea rearming or load adjustment, the rearming device is transported from the CLF ship by the new Heavy Unrep rig to the combatant ship sliding padeye along with a team to operate the rearming device. A swing arm at the base of the sliding padeye is used to position the rearming device onto three low profile rails permanently mounted atop the VLS launcher. A hydraulic power unit on the combatant ship powers the swing arm and also the rearming device after it is on the rails. 

The CLF ship will next transfer a loaded VLS canister to the sliding padeye. The canister will be lowered to the swing arm by the sliding padeye and then be released from the transfer rig. The canister will be swung around and be picked off from the swing arm by the rearming device two clamp rings. The canister will be moved by the rearming device to a position over an empty cell. The cell hatch will open and the rearming device will erect the canister to the vertical. The canister will be lowered by a wire rope hoist into the cell. The rig will be disconnected from the end of the canister, the cell hatch will close and the canister will be connected below decks to the VLS circuits. When the VLS rearming or VLS load adjustment is completed, the rearming device and team will be returned to the CLF ship.

 
The above proposal puts the VLS reloading equipment and specialized team not on the warship, as with the early crane, but on the Logistics Ship. The team and the rearming device will move on to the warship to ream at the beginning of each evolution, and will move back to the support vessel at the end.

The threat of Anti-Access and Area Denial strategies and the focus on the Pacific should both work as powerful budget and strategy drivers in the next few years to encourage the US Navy to bring work forwards on UNREP improvement. At sea logistics will be more important than ever, and we can expect to see big increases in capability.
It is worth noticing that the Heavy UNREP equipment envisaged and experimented by the US Navy appears to be very similar to the Heavy RAS equipment being experimented by the Royal Navy at HMS Raleigh in anticipation of adoption on the next generation Solid Support Ships. The wide loads being moved, in terms of bulk, and the weight mentioned (12.000 lbs) are roughly the same values indicated for the Rolls Royce H-RAS. 

 
The US Heavy UNREP equipment
 
The H-RAS facility at HMS Raleigh, in one photo from Dave Sheffield. According to the blog NavalMatters, we can expect an article on the H-RAS activities in november's edition of Navy News. The shuttle resembles that seen in the 12.000 pound mode of the Heavy UNREP kit for the US Navy, but no actual heavy load can be seen. Trials are still at an early stage

A Mk14 Mod 2 Tomahawk canister comes at 6130 pounds. Both the H-RAS and H-UNREP kit would move possibly two canisters per each lift, with a rhythm as high as 25 lifts per hour. While at-sea rearming of Royal Navy VLS ships is not on the cards, the new Solid Support vessels seem set to have the RAS capability to keep the door open for future adoption of adequate kit and methods.


SYLVER   

The European SYLVER vertical launch system follows the same principles of the MK41, but has been developed more recently, has never had any built-in at-sea reloading kit, and has made some different choices. Getting details on SYLVER is much more complex than getting adequate information on MK41, and it has taken me quite a while to collect information which is not yet as complete as I’d like.

SYLVER comes in three main sizes, in addition to the very small, self-defense for small ships A35 launcher. The main modules are the A43, A50 and A70. The number refers to the approximate length of the cells, which vary from 4.3 meters to 7 meters, roughly matching the MK41 Self Defense, Tactical and Strike lengths. The A43 launcher has a total height of 5.3 meters; the A70 is 7.6 meters tall.

DCNS, the maker of SYLVER, proudly notes that SYLVER is significantly lighter than MK41. Early claims were of 30 to 40% weight savings thanks to the use of more modern materials and composite, but this seems over-optimistic, as the declared weight of the 8-cell standard modules goes from 8 tons (A43) to 12 tons (A70).
SYLVER has a smaller deck area footprint, of 2.6 meters x 2.3 meters, while vaunting an exhaust duct which, according to DCNS, is 1.5 times larger than that of the MK41. The larger duct is meant to make the system even safer by expelling gas at lower pressure, allowing simultaneous salvo firing even while one missile has an inadverted restrained launch.

The significant difference in width of a 8-cell module (2.6 meters for SYLVER, against 3,17 meters for MK41) explains why the Euronaval 2012 model of the Type 26 had three 8-cell modules fitted abreast, while the DSEI model only had two MK41 modules sitting abreast. The first combination fits in some 7.8 meters, while the same number of MK41 modules arranged in the same way would require 9.51 meters.

The difference, however, comes at a price: the SYLVER’s cells are only 22 inches wide, 3 inches less than the MK41’s. The difference is very significant, as SYLVER of course needs its own canister, and even assuming that these are thinner, the internal diameter available for the actual missile will inexorably be less than 22 inches offered by the MK41 canisters. 

 
The current DCNS brochure says nothing of the detailed sizes of Sylver, but in older documents emerges that the SYLVER cells are 22 inches wide. Early proposals (i don't know if they went ahead or not) included developing the A35 variant using 25 inches cells, to take ESSM quad-packs and compete with MK41 on the export market. Sounds to me already like a bit of an admission that going for a smaller cell wasn't a winner.  An intermediate lenght A6X was also proposed, but never went ahead.

Although DCNS shows Tomahawk as a possible payload for the A70 launcher in its brochure, it is entirely right to question whether it would be actually possible to integrate it in the European cells. The Tomahawk missile is around 20.5 to 21 inches in diameter, so the space available to fit it, complete with a proper canister, into a 22 inches cell is truly minimal.
Integration would be a challenging affair for physical reasons, as well as for politic, economic and combat system reasons. A wholly new canister would have to be designed, and the space available to do everything that needs to be done would be minimal.
Apparently, besides, A70 canisters are circular, not square like MK41’s. 

Loading a SYLVER A70 canister on a FREMM frigate of the french navy, in an image by DCNS. The canister is circular, not square, so more similar to Russian and Chinese systems than to the MK41! 
 
There is also an unanswered question coming to mind when observing the disposition of SYLVER launchers on warships. On each vessel, the 8-cells SYLVER launchers are always in contact at most only by the short side. This can be observed on Type 45, on the Horizon destroyers of Italy and France, on the FREMM frigates and on the Formidable-class frigates of Singapore. The long side of the launcher modules is never in contact: there is always an important space of deck between one launcher and another. 

 
SYLVER A50 modules on the Type 45: two rows of three modules each, touching by the short side, but well distanced when it comes to the long side. 

 
The silo on Horizon-class destroyers. This, specifically, is Italy's Caio Duilio. The 48 launchers are arranged in three rows of 2 modules each. Very different arrangement than Type 45's one, but still there is significant space left between the rows on the long side. Compare all this space to a 4 or 8 module MK41 silo: why all this space wasted?
 
On the italian aircraft carrier, Cavour, in a photo by Chinomar, from the website Mezzi Militari Italiani

On Singapore's FORMIDABLE frigates

On Charles De Gaulle


This is not observed in MK41 silos, which show a very high density, with the separate modules in direct contact. One is left to wonder if the separation between modules is a choice made by all customers so far, or an unavoidable necessity.
Perhaps coming from the fact that the canisters themselves are thinner...? 
If this is the case, the lower deck-area of SYLVER becomes much less of a truth: basically, fitting more SYLVER modules than MK41 ones, in the same deck area, is only possible so long as the modules are installed abreast, like on Type 26. In a large multi-module silo, or in any case when the long sides should touch, a lot of space ends up wasted, for some reason.


The right choice?

It is not easy to judge which system represents the right choice for the Royal Navy. I’ve already discussed in an earlier article about this complex topic, and much of the uncertainty is due to the fact that it is not clear yet what weaponry the RN hopes to fit into the VLS cells. Of course we can assume the Tomahawk in the short to medium term and the SPEAR Capability 5 (also known as UK-FR Future Cruise and Anti-Ship missile) in the longer term (not before 2030).
For the Tomahawk, its eventual successor (American design) and for other possible weapons (LRASM?), the MK41 would be the most appropriate, if not the only choice.
Going for commonality with the US Navy would be, in my opinion, more advantageous and more wise in a long-term analysis, despite the SPEAR 5 work with France. It is very hard to see how investment in SYLVER and in its weapons by UK and France (and eventually Italy) could ever match the level of support and attention that MK41 will receive from the US, Japan and other export customers. In terms of logistics and future-proofing, MK41 would make greater sense.

It is true that it is hard to see at the moment which American weapons, beyond Tomahawk, could ever be selected for the (british) Type 26. With CAMM covering the air defence role, with Sea Viper on Type 45 in the higher tier, it is hard to see british interest for any of the American SAMs for at least a few decades.
When the UK will eventually acquire an anti-ballistic missile capability (because I believe it is a matter of “when it becomes necessary”, more than a question of “if”), we can expect that the Type 45 will be the platform of choice, so being able to embark SM-3 is also not immediately relevant.
As for LRASM, the missile’s future isn’t even certain yet, and the UK will likely not procure it, unless the SPEAR 5 ambitions collapse.
However, there are logistic, support and future-proofing reasons to go MK41. Being tied to the US Navy is the most promising way to ensure that the weapon system is not without support, evolution paths, and new weapons.

I don’t see many reasons to go with the SYLVER. Certainly not Scalp Navale, which is a less performing, more expensive alternative to Tomahawk that the RN frankly does not need at all.
The main cause of interest is the SPEAR Capability 5 missile, but this is little more than a concept, and the few studies started so far are all aimed at a 2030 entry in service, which might easily slip further to the right. If the currently envisaged timelines are respected, the first Type 26 by then will be approaching the first 10 years of service life. Betting it all on a missile that might or might not come by then, does not seem the right way to go.
The main factor, at this point, is the number of VLS cells. Having 24 instead of 16 is obviously much better and preferable under many points of view. The smaller diameter of the cells, however, which already feels tight today, is a concern for the future.
It would be important to know if the Type 26 design can spare the additional under-deck space which would be needed to replace the banks of CAMM-only cells in the bow silo with an additional MK41 module or two. If these is the possibility to do so, as has been suggested to me (but not confirmed by sufficiently authoritative sources), then my suggestion is to go MK41. CAMM could just be quad-packed into some of the MK41 cells, instead of having its own single-purpose spaces.

Even if such space does not exist, I think adopting MK41 could be, in the end, the best choice, although less evidently so. MK41 promises greater certainties for the future: there’s a much larger and richer customer base investing on it, and it has the physical size advantage. You can be reasonably certain than any missile developed for the 22-inches wide SYLVER cell will fit into the 25-inches MK41, while the opposite simply is not true.    

I suspect this is a reason behind MBDA’s decision to offer European missiles for the MK41. Of course, the main reason is the global diffusion of MK41, but I believe it is nonetheless indicative that MBDA has signed an agreement with Lockheed Martin to integrate European missiles in the MK41 cells, starting with the easier system to transfer, the very interesting Sea Ceptor / CAMM. The greater width of the MK41 cell has allowed Lockheed to develop the Extensible Launching System ExLS: a simple, yet ingenious “launcher within the launcher” which can be slid into MK41 cells (or used as a stand-alone system) to accommodate foreign missile systems, with their canisters and launch electronics. When it first appeared, it was associated with plans for quick MK41 integration of smaller weapons and even countermeasures: the NULKA active radar decoy, a quadpack of RAM Block 2 missiles or a pallet of NLOS surface-strike weapons were all shown as possible payloads.
After being demonstrated with NULKA, the ExLS has now come very much back in the spotlight for its instrumental part in allowing MBDA and Lockheed Martin to get to push-through tests with the CAMM missile in a MK41 cell in very short time. After agreeing to collaborate, in May 2013, the two companies have successfully cleared the first launch trials in September: a record for the slow world of defence technology. This success has been just as quickly rewarded by the selection of CAMM in MK41 cells for the upgrade of the ANZAC class frigates of New Zealand.  
 
CAMM test fired out of an ExLS module clipped into a MK41 standard launcher

It is also worth remembering that the US Navy has already invested in a new generation of Vertical Launch System which share the same base principles but comes with longer, wider cells. The MK57 launcher comes in four-cell modules, and is so far only known for being employed by the sole DDG-1000 Zumwalth-class. These three unique ships will have 20 MK57 modules installed, not in dense silos like on Ticonderoga and Burkes, but in peripheral position along the sides of the hull. 
The new launcher is fully compatible with existing MK41 weaponry and canisters, but offers cells which are 283 inches long and 28 inches wide, with a maximum mass of 9020 lbs. It is a very noticeable increase in all parameters from the MK41 Strike Length.
It is not yet evident which new weapons will require this big space, nor is it likely that the MK57 will replace the MK41 anytime soon. For now, it is tied to a new class of warships which has been cut down to just three hulls. It will be interesting to see if the MK57 becomes part of the requirement for the proposed Arleigh Burke Flight III, or for whatever ship comes next.
The US Navy’s belief, however, seem to be that larger missiles are likely, and while the MK57 is possibly too far ahead of the current requirements, the SYLVER might soon enough fall behind requirements.