Shipbucket

Do you mean a universal carrier design that could be exported widely? If so, it's the Holy Grail of warship design. A lot of people have worked on exactly that, explicitly to replace the British light fleets. The problem is that everybody wants their carriers to do different things and a ship that can cover all the bases is so compromised that it simply isn't worth the effort.
Unfortunately, it isn't an option. Carrier size is determined by aircraft characteristics. Essentially, what we do is a maths problem. The aircraft need to take off, ie reach flying speed. For all practical purposes that means catapulting them. Now, the aircraft has to reach flying speed which is a set point. The maximum acceleration the aircraft can be subjected to before the pilot's neck snaps is also a set point. Those two bits of data give us the length of the capapult section. The wingspan of the aircraft plus 50 percent gives us the width of that zone. That's component A.

The landing zone comes next. The deceleration applied to the aircraft is also a fixed amount. A good example of what happens if that amount is exceeded was shown in some arrester trials where the wires stopped the rear half of the aircraft but the front half kept going and went over the edge of the angled deck. Now, the landing zone also needs enough space for the aircraft to accelerate and resume flying in the event of a bolter. That total length multiplied by the wingspan of the aircraft plus 50 percent is the component B.

Finally there's the deck park area. This is the space needed to move aircraft around, park them, ready them for launch or for striking below after retrieval. The area here is a key part of the aircraft carrier's efficiency; if she's short on space here, she won't be able to operate her aircraft effectively. This is component C

Finally we have to decide how many aircraft we want to be able to launch at once. Then, we multiply A by that number, add B and C and we have the total area of the flight deck. Note this is largely driven by the performance and size of the aircraft, not by any desire on how big the carrier should be. Essentially, we have a flight deck and we put the ship underneath it. That tells us such things as how many aircraft the ship can carry and everything else. If we design a smaller ship, we have to accept compromizes on aircraft operating capability. That eans reduced payload for the aircraft, inability to launch aircraft rapidly, inability to bring them back on board quickly, inability to tailor strikes or keep alert aircraft up on deck. All that good stuff. So, the smaller carrier doesn;t just have fewer aircraft, a lot fewer per ton by the way, but she can't use them as effectively. Also, she's likely to have less fuel for them and fewer munitions.

Basically the way it works is that if one has 100,000 tons to invest in carriers; the max capacity of the 100,000 ton ship will be 90 birds while the three 30,000 tonners with probably carry around 24 each. The big catch is that in actual operability terms the ratio won't 9:7 but 8:5.

Also, each carrier requires an overhead (hotel load) of aircraft regardless of her size. This incudes a couple of AEW birds, probably four ASW helicopters (no, she can't rely on her escorts for those; tthe carrier can operate them in wetaher conditions that prevent teh destroyers and frigates from doing so) and at least one utility bird. Say six in total. So, the 30,000 tonner really has 18 strike birds and 6 utility while the 90,000 tonner has (theoretically) 84 strike birds and 6 utility. That brings us to roughly 8:5 odds in favor of teh big carrier and, once operability is included roughly 2:1 in favor of the big carrier. In reality what this means is the big carrier cand evote more of her capacity to support riole aircraft (tankers, EW birds, etc etc etc).

Finally, cost isn't related per ton. Most of a ship's cost is determined by her systems costs. Hull and machinery cost are 10 - 20 percent of teh total. So, the 30,000 tonner actually costs around 50 percent of the 90,000 tonner. So the balance really is that the three 30,000 tonner fleet costs 50 percent more but offers half the capability than a single 90,000 tonner. Which is why the USN doesn't build the smaller carriers.

My Fuhrer....I can find WIN!



Chart found in

Handbook of U.S. Aircraft Carrier Programs
by
Director
CV and Air Station Programs Division (OP-55)
DCNO (AIR WARFARE)
OFFICE OF THE CHIEF OF NAVAL OPERATIONS

found at the Navy Yard Archives -- the book used to be a mix of CONFIDENTIAL and UNCLASSIFIED sources; it's now been declassified completely.

As a followup to Stuart's comments on why carriers are the size they are, something else he wrote about a specific carrier, Charles de Gaulle, that many here have probably read before but it may be new to some of the new members.

http://www.tboverse.us/HPCAFORUM/phpBB3 ... f=11&t=936

There's little doubt about the fact that an LHD derivative would make a good aircraft carrier – in fact, the new LHA-6 class is more or less just that. It's an LHD-1 Wasp class with the well deck aft stripped out and its aircraft operating capabilities enhanced. Actually, she derives from the LHD-8 Makin Island but that's a detail. The thing is that these ships are big. The LHD-1 class are officially 41,000 tons full load but are actually closer to 45,000 tons. LHA-6 will be (officially) 45,000 tons but will really be closer to 50,000 tons. The Queen Elizabeth class are officially 66,600 tons (I love that displacement) but are really going to be closer to 68,000. So, LHA-6 is about three quarters the size of the Queen Elizabeth. LHA-6 currently costs around US$3.2 billion, officially the cost of Queen Elizabeth is US$2.4 billion but it's pretty clear she'll cost a lot more than that. I'd say that the two classes are probably about even in real costs.

However, the devil is in the details.LHA-6 doesn't have the equipment (command systems and so on) to conduct the kind of power-projection missions as the QEII. She lacks the ability to rapidly re-arm and refuel strike aircraft on deck. She can't launch the kind of mass strikes that the QEII's mission profile needs. What LHA-6 does have is the equipment needed (command systems and so on) to manage an amphibious operations. Internally she's designed so large numbers of heavily-armed marines can move around her quickly and efficiently. She has over-sized hatches to allow big men with lots of guns to get through them easily. She's designed to operate a steady stream of small numbers of fixed-wing aircraft so that the troops on shore have air support when they need it. So, although the two ships appear similar in size and cost, they are actually quite different animals.

The point about LHA-6 though is that she's a big ship. She's about the same overall size as one of the old Midway class carriers. That's why nomenclaturing them as a CVL is so misleading. They are anything but a CVL. Most navies can't operate ships that size. They don’t have the berthing facilities, drydocks or maintenance facilities. A ship like LHA-6 is probably restricted to, at most four countries, three of whom prefer to build their own designs.
On, it can be done, the question is how close were the original specifications? The Chakkrinareubet and the Principe are a good example here. In fact, the original specifications of the two ships are superficially very similar. The driving force behind both designs was to keep two helicopters airborne simultaneously. Working backwards from that requirement determined number of helicopters carried and that determined flight and hangar deck size and so on. What was different was that the Spanish Navy planned to use their ship for ASW while the Thai Navy wanted theirs for maritime policing. Thus, the two helicopters were ASW birds for the Spanish and utility birds for the Thais. The big concealed difference was that the Spanish ship required an ASW command and communications system, a battle management system, sonars, on-board processing and so on. The Thai ship needed none of that stuff. So, converting the design was easy, the Spanish simply left off the ASW specific stuff and the space was converted to Royal apartments (suiting the ship to flagship work).

In most cases though, conversion from one country's requirements to another are not easy. For example take the Australian LHDs. The Canberra class is a version of the Spanish strategic projection ship Rey Juan Carlos. The ships have the same role, will deploy the same aircraft (and yes, the Canberras will be capable of handling the F-35B even though the RAAF hasn't caught on to that yet) and will do much the same things. Yet there's a lot of redesign needed. Things like extra air conditioning for tropical operations for example or datalinks that allow operations the Spanish can't undertake. Different radars require different superstructure layouts and so on. As always, the devil is in the details.
The experience with the French in multi-national design is not good. Horizon is a complete disaster – four ships built out of a planned 22 and they aren't worth much. French participation in the design was responsible for the program being ten years late, way over cost, technically compromised and a general nightmare. FREMM Seems to be going much better, primarily because the Italians walked out of the meetings every time the French started playing head-games and refused to return until the French conceded the point. The French have pushed their PA2 program back at least five years now and the presumption is they won't be going ahead with it.
La Fayette was actually designed as a replacement for the export frigates of the 1970s and the French version is a sort of plug and play basis on which the others are based. Except the Formidables, they aren’t really La Fayettes at all. They're sort of proto-FREMMS.. The U.S. carrier fleet is an odd case. Essentially the number of carriers is set by Congress, the hull life per carrier is set by design and the building rate set by dividing hull life by fleet size. The effect is roughly one carrier every five years and the result is a series of one-ship classes. They're called the Nimitz class but in fact every ship is different. That's inevitable.
Ski-jumps have quite a few operational problems and whether the limitations they impose are worthwhile is a matter for individual navies. Devil in the details again. By the way, the Harrier also causes heat damage, it's inevitable with VSTOL I fear. It is possible to design a carrier so that the only thing needed to change from VSTOL to CTOL is the switch of two modules but that's an option for bigger ships.

The proposed second Vikrant class carrier may use the same electromagnetic catapult system modern American carriers, and the proposed British carriers do, and is about the same weight and capability. Considering, unlike the British, the Indians haven't had a history of carrier design, its quite ambitious.

The Indians have a long history of presenting ambitious and exciting plans that never come close to completion in their original form. Wait until we see what comes out of the building yards first.
Actually it depends on operational requirements. When those exceed the capability capacity of a ship that could be afforded by the navy in question, they dropped out the carrier game.
No, she's an OPV with a big deck and hangar. She's not really a carrier at all.
There's no doubt that carriers are the most flexible ships around. All one has to do to change roles is to change the air group. Only, it isn’t quite that easy. Different roles require different ship-fits. We've touched on the differences between an LHA and a carrier in terms of internal arrangements. Add a diocking bay for an LHD and the compromise of carrier characteristics becomes severe. UAVs take a lot of handling on deck and that presents problems all of its own. So, yes, carriers are very flexible but that flexibility isn’t infinite and it doesn't touch on the problems of national differences.
The big difference is that an aircraft carrier battle group can kill an enemy from several hundred miles away.
All true. Hence the standard definition of a CVN. "100,000 tons of diplomacy."
If there is a CVN around, we have got overwhelming superiority. One CVN recently deployed with eight AEGIS ships around her – that's enough firepower in her escorts alone to shoot down every non-American maritime aircraft in the world twice over
The Brits had no AEW, poor radars, no dedicated fighters, lousy point defenses and some Captains who were better off navigating desks. They still did pretty well against missiles. If somebody lays a nuke on a USN CVBG, everything is over – for them. Within a few minutes they will be flat, black and glowing in the dark. There's an old saying for this. One flies, they all fly. The defense of the carriers against nuclear attack isn't missiles or electronics or whatever. It's what will happen to your country if you try it.
Therein lies the rub. What you are saying sounds easy enough but it's the doors to a world of hurt. I'll give you an example. On Horizon, the French demanded that Sagaie be used as the chaff/flares. The British and Italians wanted Sea Gnat as a result of their NATO commitments. Sagaie loads horizontally, Sea Gnat vertically. Beneath the launchers were compartments that served other purposes. To install Sea Gnat, it was necessary to move those compartments and install the Sea Gnat magazines underneath. So, the Italians and the British made the changes to the superstructure design. Now, under the terms of the CNGF Horizon plans, each change had to be signed off by all three partners. So, the revised plans went off. When the British and Italians got them back, the French had changed the design back to its original layout. The Brits and Italians refused to sign off, changed the design back to their layout and off the plans went again. Only for the French to change them back again. That went on for two years until the British walked out. Now, that might not sound much but the plans for the radar installation couldn't go ahead until the superstructure configuration was settled. The plans for the weapons installation couldn't go ahead until the radar installation was settled. The specs for the command system couldn't be decided until the weapons installation was finalized. And so it went on. The whole program was at a complete standstill for those two years (and we won’t even go into the Conze Affair).
It's been tried. The problem is that for a major contract that size, the client wants to build it in their own yards. So that means licensed construction and all that entails. Also, as a rule of thumb, multi-national program costs double with each additional member. Getting the four countries you list to agree on anything would be a miracle.

The only way to do this is to get a group together and get them to agree on common systems where possible. The way the Dutch, Spanish and Germans agreed on the Tripartite Frigate Program. That ended up with De Zeven Provincien, F-124 and Alvaro de Bazan. Three quite dissimilar ships but enough commonality to save some cash. The tripartite frigate program started three years later than the CNGF Horizon, finished four years earlier and delivered twelve ships out of twelve planned.
The problem is getting the price right. As I said, this idea has been floating around for a long time and the problem is that nobody has bitten. Most navies simply don’t have the infrastructure and have other, more pressing needs.
The big carriers make a lot more sense than the small ones; they offer hugely more firepower and not that much extra money. A repeat CVN-77 will cost around US$6 billion but gives an order of magnitude more punch. The smaller mid-sized carriers QEII/CdG cost about half that and offer about a third of the punch if that. The small Amphib-based carriers aren't even in the same running. They're a threat to a frigate Navy but that's all. If real carriers come calling, they're dead. It’s the small ones that make only limited sense.
Any nation that wants to be considered a serious regional player.

Also, LHA-6 is gas turbine powered
All excellent points. Need extra galley space as well; food on British ships is much better than American. And you'll need to find space for a bar.
The small ones yes, the big ones are different. They require a lot of ground handling crews lest they roll over the side and are gone forever. We've been doing a lot of quiet experiments on this area and the numbers do not look good.
Have we met????
Ah, well, one might be faced with gangs of desperate refugees. . . . . . . A Polish friend of mine described her as "The Modern Schleswig Holstein" (See identity of ship that fired the first shots of WW2)
Two thousand yards. One doesn't want self-frying rump steaks descending on the flight deck.

MEKO didn't work at all well; it ended up being a design tool to vary armaments and it's virtually gone with MEKO-A
Both want to build locally. Brazil is likely to opt for something like the Spanish SPS. I honestly can't think of a candidate. Most countries want their navies to patrol their EEZs and half a dozen OPVs are much more effective than a single light carrier. To buy a carrier means getting into the power projection business and that means real carriers.

I think that sums it up neatly. If I might enhance it slightly.

To get a multi-national program off the ground there has to be

Commonality of Ship Role/Mission
Commonality of Budget
Commonality of Political Will

To make a multi-national program succeed there has to be

Commonality of Aircraft
Commonality of Support Capacity
Commonality of Building Location
Commonality of Equipment used
Commonality of Weapon Loadout
Commonality of Goodwill

You don't know the half of it. The Project Manager had no idea what he had let himself in for. Every time I met him, he had that deer-in-the-headlights look
Brazil's talking about looking. They're one of the candidates for buying a QEII if that's the way things crumble. Rumors that the RN is bribing Argentina to ask about buying a carrier have been officially denied.

The simple answer there is that it isn't. The pre-eminent aircraft carrier design is CTOL with catapults and wires. The problem is that you're mixing up two kinds of ships that have different operational roles. This really stems from the way you are using the term "Light aircraft carrier" to describe ships that are not aircraft carriers at all.

Aircraft carriers are designed to operate fixed-wing strike aircraft. Period. Everything is secondary to that role. They may use those aircraft for a variety of roles and may fill a variety of operational niches with them but they are still designed around the operation of those aircraft. For such ships, catapults and wires are still the standard. I would point you at the U.S. Navy's CVNs which still represent the bulk of the world's carrier fleet both numerically and in terms of investment and the French who used catapults and wires on the CdG despite the major design problems the installation caused. The reason is quite simple; catapults and wires allow the user to get the best possible use out of the aircraft on board. They allow the aircraft to take off while heavily loaded and offer the most fuel-economic way of doing operations.

The LHAs and LHDs (and LPHs) are not "light aircraft carriers". They are amphibious warfare ships. Their job is to put a landing force ashore by a variety of means. This is a totally different design requirement and one that puts an enormous burden on the ship designers. An amphibious warfare ship is just as dedicated to its role as an aircraft carrier is to its. The major demand for an amphibious warfare ship is that it should carry its Marines to the scene of their operations in a fit and healthy condition and then transfer them to the shore. Everything including aircraft operations is secondary to that role. Notice that the majority of LHAs, LHDs and LPHs are flat-decked. The reason why is because a ski-jump takes up enough deck space to allow for one or two helicopter landing spots. For an amphibious warfare ship, those spots are more important than any advantages the ski-jump may confer. I would point you at the U.S. Navy's LHAs and LHDs, the British HMS Ocean, the French Mistrals, the Japanese Hyuga class all of which show this trend.

Where the ski-jump fits in is where an amphibious warfare ship is also operating a few VSTOL fixed wing aircraft, primarily to support the troops ashore. What the ski-jump offers is the ability to improve the capability of those aircraft without incurring the design costs of installing catapults and wires. Those are expensive items to install on ships (here, expensive does not refer to money but to the penalties inflicted on the design. Installing catapults and wires on an amphibious warfare ship would mean a major reduction in its ability to carry and service the troops on board. Thus it would represent sacrificing the ship's primary role in favor of a secondary role). In design terms, the ski jump is a very limited cost item; about the only costs associated with it are the loss of the aforementioned helicopter operating spots. In financial terms it is also very cheap.

So, if a Navy has an LHA/LHD but no carriers, a ski jump offers the ability to get some extra use out of the fixed-wing aircraft on board without too much disruption of the ship's primary role. Now, let's go back and look at the worldwide pattern with this in mind. Suddenly, the pattern does become very obvious. Countries that have proper aircraft carriers and amphibious warfare ships have flat-deck LHA/LHD type ships. Countries that have amphibious warfare ships but no aircraft carriers put ski-jumps on their LHA/LHD type ships.

This brings us to the two exceptions. The Royal Navy and the Indian Navy. Dealing with the latter first, at the moment they're stuck with the ski-jump because that's what they always had and their aircraft fleet is Harriers and the only way to get any decent range/payload out of a Harrier is to use a ski-jump. We don't know what is coming out of their shipyard for the new Vikrant class; all the released drawings and models are "speculative" (official description). The Vikramaditya was also determined by the need to modify an existing ship.

The Royal Navy is also stuck. Originally, the two CV(F)s were due to enter the fleet before the F-35 would be available and the ships would have operated with an interim Harrier/helicopter group until the F-35 was available. That meant a ski-jump. So that drove the ski-jump F-35B decision. Now, QE2 has been so badly delayed that she'll come into service about the same time as the F-35. There's a good school of thought that QE2 will be completed with a ski jump and PoW with catapults and wires. Then, when PoW enters service, QE2 will be sold or used as an LPH.

So, really the ski jump isn't "pre-eminent" at all. It's a niche solution for a specific requirement. Catapults and wires are the pre-eminent solution for true aircraft carriers.
Way no. Take a look at the French Navy for an example of why that is not true. They turned down Jaguar-M in favor of Super Etendard and F-18 in favor of Rafale, in both cases rejecting a superior and less-expensive aircraft in favor of their own product. Getting people to standardize on aircraft in any context is very hard.
It’s a good general principle not to change everything at once but it doesn't really apply here. I don’t like F-35B either, more because I have grave reservations about the whole principle of vertical take-off aircraft as a result of reading too much garbage about them in the 1980s. I think the British should bite the bullet, accept that QE2 is cost-overrunning and late anyway and switch to catapults, wires and the F-35C. They could then standardize of the F-35C as their front-line combat aircraft and throw the Typhoons into the sea. That would actually save money in the long term. The British have made up their minds; I happen to think they made it up the wrong way but that's just me. They've still got time to put it right though and the QE2 is designed to make switching from ski-jump to wires relatively easy

That's actually a major design issue. Airflow over the ski-jump is a serious matter and it acts as one of the factors determining the angle of the jump. Another problem is spray from head seas. That can cause serious problems and also result in damage to the jump. On the Vikramaditya, the new ski-jump bow is actually wrapped around the old bow structure - the old bow is still there, inside the new one. How that is going to hold up to a heavy sea is going to be interesting

On paper I agree, but don't neglect the possibility that cancelling one will become an end within itself rather than a means to an end. "Get the carriers" is still a noted phenomena within elements of the RAF and Army. After all, the original financial arrangements for Type 45 were supposed to make it too expensive to cancel any of the original twelve. Having said that, I think the RN will end up getting both ships, initially at least. The problem is that they might find one being sold out from under them for pennies on the dollar. I think that's a reasonably accurate prophecy. I don't discount PoW ending up with catapults and wires though while QE2 becomes the duty LPH. I think that is an optimal solution. Buy F-18Fs as the airgroup for one carrier and supplement them with F35Cs later.

She doesn't need extra powerplant; she's already faster than the CdG (which poodles around at 23.5 knots). The extra weight is a partial contribution for the catapults and a general desire to be "bigger" than the RN ships. To be honest, comparing like for like, I doubt if the French ship is much heavier than the British one. Still, the French ship is paper only at this time so who knows what, if anything, will finally come out of the yards.

It's a bit more complicated than that. The decks end up being suited for different things. With a standard carrier deck (cats and wires), the launch area is constant with a large parking area behind it. This means that a large strike can be readied for launch and prepared to go. Now, how fast those aircraft can be cleared from the deck depends on how many catapults the carrier has. For a CVN with four catapults, a group of four aircraft can be launched per cycle and that's a lot faster than any ski-jump carrier could ever manage. Two catapults, not so much. However, the key point is still that park full of bombed-up aircraft that allows the carrier to launch a massive strike (an alpha strike) that can take down a heavily-defended target.

With a ski-jump, the aircraft needs a considerable run up to the jump. This tends to reduce the size of the parking area. Also, the ski jump can only be used by one aircraft at a time so the launch rate is actually quite slow. What these factors tend to mean is that teh ski jump configuration is best suited to an environment where a trickle of aircraft constantly available is required. So, the operational modes of the two ships are quite different.
This is largely mythological I fear. The weather advantage of the ski-jump is something the RN like to crow about but a lot of it is that they simply allow operations in worse weather than the USN do. In the crunch, the weather handling capabilities of the CVNs are much greater than those of the small carriers.
Again, it's more complicated that that. The problem with big carriers is that, beacuse of their ability to launch major formations of aircraft, they do just that. They swamp the battlefield with aircraft so for the troops ashore, its either feast or famine, hige numbers of aircraft overhead screaming for targets or none at all. The STOVL carriers give a constant thin stream of aircraft. The big problem is that the latter works fine when there is no opposition; if there is opposition, that thin stream of aircraft can get destroyed in detail. Again, we come back to operational modes and how, if there are big deck amphibious ships available, the owning Navy doesn' even consider ski-jumps

This is all true; a lot depends on size and analysis is complicated by the fact that ski-jump carriers are smaller than cat-and-wire designs. I don't doubt that as size shrinks, cat-and-wire becomes less attractive and ski-jump more so. The ski-jump allows fixed wing aircraft operations on hulls that wouldn't normally permit it at all using cat-and-wire. There is a point where ski-jump carriers become more operationally effective than cat-and-wire. Where that point is is a matter of debate. Personally, I put it at around 35,000-40,000 tons (meaning CdG was right on the borderline). That debate is complicated by the fact that nobody has built a large ski-jump carrier so QE2 is right on the borderline.

I have to disagree on the recovery rate. Recovering by vertical landing is slow. What distorts this is that normally cat-and-wire carriers operate far below their maximum available rate for safety reasons. The comparisons are normally made between a cat-and-wire carrier at its normal safe speed and a ski-jump carrier at maximum speed. The same applies to launches by the way. Another factor to consider is that Royal Navy ship handling in general is far superior to that of the U.S. Navy. RN officers are simply much better trained (at every level of their professional development) than their U.S. equivalents. This means that they are happier to do things in conditions that are considered preclusive by the U.S.
It's a combination of training and safety factors. The gap is between what cat-and-wire can do and what it normally does. Again, the RN will do things in weather conditions that the USN will not consider. It's a training issue, not a technical one.
Experience tends to be there's a lot of design art thrown in here but the main change point comes at around 35,000 tons. This was the big lesson with Lexington and Saratoga, they could run and operate aircraft in much worse conditions than the smaller carriers. Hence the US predeliction for big carriers. There is another big jump at around 65,000 tons. Oddly, QE2 is over both size humps so she should be in the area where cat-and-wire give big benefits.
In which case; why build a big carrier? The only point of building carriersthis size is to carry and operate lareg airgroups capable of flattening the opposition. For the kind of trickle operations you''re suggesting, the RN would have been better off with five 25,000 ton enlarged Invincibles. That would also solve the LPH problem.

Stuart, how much did experience with operating from Foch and Clemenceau influence the French choice of cat and wires for Charles de Gaulle?

I don't think the French actually made a choice; they never considered anything other than cats and wires. To do so would have meant them scrapping Rafale-M and buying Sea Harriers. After a decade of ridiculing the Sea Harrier and everything it stood for, that simply was not an option. Anyway, Dassault would not have stood for it.

Clemenceau and Foch were basically 27C Essexes with all that implies. They were just about OK for the generation of aircraft they had to handle but that's all. So, I don't think the French really used the experience from them at all.