March 23, 2018

Why do we need so many ships?

The following came out of an SSC conversation with Le Maistre Chat. I've rewritten both sides to make it flow better, but I've done my best to preserve the core of the discussion.


Five carriers and other ships moored at Norfolk Naval Base (click for larger version)]

Le Maistre Chat: Explain to me why the Navy needs as many ships as the next 17 powers combined when the British Empire maintained hegemony of the seas with a 2-power standard. I’ll start decommissioning while you talk.

bean: I'd better talk fast then. There's two major aspects to it.

The first is the changing nature and use of sea power. In 1889, when the two-power standard was established, battleships had little use beyond controlling the sea. While this was and is a vital role, and it also meant they could land troops ashore, they didn't have anything like the ability to influence events ashore that we do today. A US carrier group (CVBG) is more powerful than the vast majority of national air forces, which means that we can take on most countries with a mobile force that we don't need diplomatic permission or existing bases to deploy. So the carriers allow us to trade off land forces and land-based air forces.

The second is geography. Britain was nicely positioned so that it was astride the lines that the potential enemies had to take to get to the open ocean. So they could essentially keep their ships at home, then send their entire force to face down the enemy whenever he came out. Even this started to fray fairly quickly. The US was essentially assumed to be neutralized diplomatically, and when the Russians got a foothold in the Far East, the British abandoned their "splendid isolation" and signed the Anglo-Japanese Alliance.

Obviously, the US can't keep our carriers at home like that. We have to deploy them, and because we need to keep them functional and crewed, it takes about three carriers to keep one forward-deployed. We don't have an empire to base them in, we need to give them time in the yards and most importantly, if we keep our crews away from home for more than 6 months at a time, they won't reenlist. So the size of the fleet is set not by the considerations of total war, but by the need to sustain deployments long-term, and what we can afford to support.

Le Maistre Chat: So we need 3-4 carriers for each one that’s out doing our bidding. How many do we need out doing our bidding? Surely no less than 3, so that puts the floor at 9 battle groups.

bean: Which is quite close to the current force structure, where we have 10, although they're trying to go back up to 12.

Le Maistre Chat: But what about the Wasp class ships? With F-35s replacing the Harriers, why do we need two complete fleets of aircraft carriers, one CVNs and another for the Marines? Billion for billion, which of these navies is going to be more efficient at ruling the oceans and providing our ground troops with air support we don’t have to ask permission for? And then there's the America class, which sacrificed the well deck because being more of an aircraft carrier was considered more relevant to the Marines than storming beaches.

bean: The LHDs and LHAs have a very different mission from the CVNs. First, we need to separate strike missions from supporting ground troops. The CVN is set up to run strike missions, and there are a lot of times when national policy doesn't need troops on the ground, it just needs to blow up something important to someone else. The recent Libya intervention is only the latest in a very long line of these kind of missions. The F-35B is going to be a lot better than the Harrier at that, but STOVL imposes a lot of limits on the aircraft, not least payload, and the CVN comes with the capability to do basically everything a land-based air force can do.

The other aspect is that the Wasps and Americas are not designed as aircraft carriers. Their primary mission is to move troops ashore. This has had a big impact on the design. America, which I've been aboard, has big corridors for loaded Marines, and lots of vehicle storage. Not to mention that they can only carry about two sorties worth of weapons for a notional fighter group, and not that much more in terms of aviation fuel. So they're not as good as aviation ships as you'd think. The Harrier/F-35B capability is a nice bonus, but it's not what the ships are for. If it was, they'd have ski jumps. And they've actually reversed course and given the third and following units of the America class well decks.

Le Maistre Chat: I still can’t fathom what mission we need 6 battle groups deployed for.

So the CVNs are for giving our ground troops anywhere in the world air support without having to ask permission for bases, and the amphibious assault carriers are for supporting our group troops on the coast? The problem with those missions is, as soon as our troops invade a Third World country, their fighting men take off uniforms and attack us with Kalashnikovs, IEDs, and man-portable missiles while looking like civilians, and our troops lose.

It looks like we have this unfathomably large and expensive Navy for the purpose of supporting an Army and Marines who don’t know how to win a war unless we fight a Great Power and they throw their industrial capacity at ours while politely not using their nukes even if we win (and that’s the only kind of war we know how to win) and occupy their capital.

bean: Not at all. The CVNs are for strike missions more than air support. Any large-scale ground operation will almost certainly need nearby land bases. The deployed LHDs/LHAs and other amphibious ships give us the ability to put a reinforced battalion ashore anywhere there's water on short notice. That may be for an invasion, it may be for disaster relief, or it may be because we need to get our embassy out of the middle of a revolution. In a lot of cases, this is an important capability, because getting a basing agreement implies political commitments on our part, too. The freedom from those, in cases where we don't need to be on the ground forever, is valuable. In fact, the initial invasion of Afghanistan is quite a good case of amphibious forces being used this way.

Ultimately, the Navy is set up to retain control of the sea and project power ashore, in the form of either missiles or Marines, pretty much anywhere. This is independent of the Army. Back before WWII, Marines (and not just ours) were the chosen force for colonial wars because they didn't carry the diplomatic repercussions of deploying the army. As we scale back our land commitments in the Middle East, that's probably going to be the case again.

Our current fleet strength is set by a balance between what we'd like to have and what we can afford to support. Part of being global hegemon is being able to project our will all the time and on short notice. Our current fleet is built to do just this, without breaking the bank or leaving us too weak to protect ourselves, and it's sustainable over the long term.

Comments

  1. March 23, 2018RedRover said...

    Bean,

    Interesting conversation. A few questions spring to mind:

    1. In a real war, are there any estimates what operational tempo could be sustained, relative to the current ~1/3? I imagine, like most things, it depends on your assumptions, but would 1/2 be a good estimate? What do they see as attrition from the enemy?

    2. Related to the above, has the carrier force looked into a blue/gold type thing the way the SSBNs operate? Obviously this would increase manning and personnel costs, but it would also increase utilization of the assets and maybe decrease procurement costs, depending on how much time they need to train on the actual ship versus what can be done on shore/at home. I'm sure they have, but I wonder what the reason against it is.

    3. I also have some jumbled thoughts on the LHA vs CVN thing. CVNs are obviously more capable, but also more expensive (20 F-35Bs on a $3B platform with ~1k crew versus 65+* F-35Cs/F/A-18s on a $10B platform with 2500 crew). The ability to have dispersed credible air support (i.e. you can afford two or three LHAs for the price of one CVN, so you can have credible force in two or three times as many places) seems valuable in theory, and also helps with attrition in battle (because each ship sunk represents a loss of only twenty F-35s instead of 60), but I'm not sure how useful that is in practice. Having the greater absolute capability of the CVN may outweigh the dispersion advantages of the LHA, or it may not.

    Also, while the humanitarian aid, embassy evacuation, etc, stuff is nice (and important), it doesn't seem like those are critical enough that they should weigh on procurement and operations decisions, if for no other reasons than the ability to offload a lot of that to the MSC**, or in the alternative to buy more LPDs.

    I kind of agree with Le Maistre that LHAs (and indeed the whole amphibious fleet) have a fairly narrow range of utility, as they're overbuilt for marginally contested operations, like the African interventions that France has undertaken, but most credible enemies (China, Russia?, Iran??, NK??????) are strong enough that they would likely make an opposed amphibious landing untenable, or at least very costly compared to a traditional land invasion where the US has time to build up its forces and its logistical tail. Given their low cost compared to the blue water fleet, it's probably still worthwhile. I think it's at least worth considering the idea that we would be better off with more CVNs for strikes, supporting covert teams, and putting the all around fear of your favorite deity into upstart leaders; and shifting the amphibious fleet more towards LPDs or MSC ships to reflect the unlikehood of having seriously contested landings going forwards. (And let's be honest, if it were seriously contested, you would have a carrier group or two to support the amphibious group, which reduces the importance of having a native LHA capability, at least to me, given how many more sorties a carrier can generate per day relative to an LHA.)

    I suppose the LHAs also have value as small carriers in the CVE tradition, but given the rest of their design (welldecks, etc), and the lack of E-2/C-2 capability, I'm not sure how useful they would actually be for that, except as a stopgap.

    To be clear, I think LHAs make sense, and given how the rest of the force is structured they seem cheap for the abilities they have, but at the same time I wonder if we shouldn't at least think about how useful those capabilities will be in the future.

    As I said, a bit jumbled : )

    *The specs for the Ford class are 90+ aircraft, but this includes the various support aircraft (C-2, E-2, MH-60, etc), and also the Navy is only buying 480 F-35Cs and has about 500 Super Hornets. Taking out aircraft for training, maintenance, attrition, and so on, 65 seems a decent estimate.

    **MSC already operate the hospital ships and could conceivably operate a "disaster relief ship" that would be optimized for that role, if built to commercial standards.

  2. March 23, 2018RedRover said...

    In editing the above, I deleted one thing which seems important, but hard to quantify: a credible amphibious force forces an enemy to hold some of their forces in reserve to counter that threat, even if the main invasion is from another direction, as was the case in both Iraq wars. This has value, but I'm not sure how much.

    Also, I think we're generally better off with an over-capacity military that doesn't do much except train, rather than a slightly under capacity one that leaves us wanting, so I'm not opposed to a large or expensive Navy (or DoD) by any means. However, if we're going to spend the money, we might as well get the most utility out of it as we can.

    (Flipping the above on its head, would we be better off with more CVE type carriers than the current whiz bang CVNs? These would still be dedicated aviation platforms, with proper catapults and arresting gear, but by having more and cheaper units, they could be in more places with a reduced operational tempo. This would obviously be disadvantageous in an all out war, but for peacekeeping/the President is concerned about the situation type things, a CVE off Liberia or Myanmar is probably as effective as a CVN.)

  3. March 23, 2018bean said...

    In a real war, are there any estimates what operational tempo could be sustained, relative to the current ~1/3? I imagine, like most things, it depends on your assumptions, but would 1/2 be a good estimate? What do they see as attrition from the enemy?

    Depends on what you mean by “in a real war”. If we somehow end up in a long-term conventional war with China, I’d say that we’d probably do about 2/3, disregarding combat damage. But that’s a really unlikely scenario. If we had to push it for a couple years, 1/2 might be feasible in a slightly less frantic scenario. Attrition is anyone’s guess.

    Related to the above, has the carrier force looked into a blue/gold type thing the way the SSBNs operate? Obviously this would increase manning and personnel costs, but it would also increase utilization of the assets and maybe decrease procurement costs, depending on how much time they need to train on the actual ship versus what can be done on shore/at home. I’m sure they have, but I wonder what the reason against it is.

    There’s a couple of aspects. First, keep in mind that SSBNs are fairly lightly crewed, and have shorter deployments, so manpower costs make up a lower fraction of total costs. Second, they don’t have quite the same workup requirements that carriers do. I know that sounds weird, but fighting an SSBN is really easy compared to fighting a carrier. You do your best not to get detected, then come close to the surface and fire your missiles where you’re told to. A carrier is much, much harder to use effectively. The typical 18-month deployment cycle runs 6 months of yard/leave/rest, 6 months of training, and 6 months of deployment. Going to Blue/Gold might shave a few months of yard off, and maybe the more frequent deployments could cut training a bit, but you’re doubling manpower to get a fairly minor improvement in utilization.

    Having the greater absolute capability of the CVN may outweigh the dispersion advantages of the LHA, or it may not.

    I’m strongly of the opinion that it does. LHAs are not designed to be little CVNs. They don’t have the ammo or fuel capacity to do so, nor do they have the maintenance and C3I facilities to support strike operations. Also, they’re usually full of transport helicopters.

    Also, while the humanitarian aid, embassy evacuation, etc, stuff is nice (and important), it doesn’t seem like those are critical enough that they should weigh on procurement and operations decisions, if for no other reasons than the ability to offload a lot of that to the MSC**, or in the alternative to buy more LPDs.

    Note that humanitarian aid and embassy evacuations are very different things. Yes, a humanitarian aid ship is possible, and some countries, mostly in Europe, have looked at that sort of thing. But they tend to come out looking more than a little like amphibious ships. My point there, though, was that amphibious forces have more capabilities than just storming the beaches of Normandy. The ability to put American boots on the ground on short notice and with the capability to handle most problems is really powerful. If all we want to do is disaster relief, we can do it more cheaply, but it's included with amphibious capability.

    LPDs are useful, but not perfect. They don’t have the aviation capability necessary for modern amphibious warfare. Everyone with any serious amphibious capability has an LPH or LHA.

    I suppose the LHAs also have value as small carriers in the CVE tradition, but given the rest of their design (welldecks, etc), and the lack of E-2/C-2 capability, I’m not sure how useful they would actually be for that, except as a stopgap.

    You’re still looking at it wrong. Note that there’s no V in LHA, but there is an H. They are designed to take troops and move them ashore via helicopters. The fact that we can stick a few rather poor strike fighters aboard to provide minimal strike capability to the commander of a landing force does not make them carriers. They are designed around helicopter operations. A typical LHA/LHD carries a dozen V-22s, a dozen other helicopters and 4 Harriers. This is a pretty good breakdown of what sort of job it’s expected to do.

    To be clear, I think LHAs make sense, and given how the rest of the force is structured they seem cheap for the abilities they have, but at the same time I wonder if we shouldn’t at least think about how useful those capabilities will be in the future.

    But those capabilities are vital for even medium amphibious assault work. A CVN doesn’t normally deploy with a bunch of cargo helicopters, and when we’ve tried to use them as LPHs, we’ve had all sorts of trouble. An LHA is designed to carry troops and move them into helicopters easily. A CVN is not. It’s a bad idea to berth a squad of Marines three decks and 500 ft of corridor away from their platoon sergeant, but you have no choice. They will get into trouble. And those corridors are not designed for men in combat gear, either, so loading the helicopters will take a lot longer.

  4. March 23, 2018bean said...

    Also, I think we’re generally better off with an over-capacity military that doesn’t do much except train, rather than a slightly under capacity one that leaves us wanting, so I’m not opposed to a large or expensive Navy (or DoD) by any means. However, if we’re going to spend the money, we might as well get the most utility out of it as we can.

    Agreed. I just don't think the amphibious capability is a waste.

    Flipping the above on its head, would we be better off with more CVE type carriers than the current whiz bang CVNs? These would still be dedicated aviation platforms, with proper catapults and arresting gear, but by having more and cheaper units, they could be in more places with a reduced operational tempo. This would obviously be disadvantageous in an all out war, but for peacekeeping/the President is concerned about the situation type things, a CVE off Liberia or Myanmar is probably as effective as a CVN.

    Absolutely not. For several reasons, the idea of a small, cheap carrier is a terrible one. The problem is that the nature of aircraft and shipboard aviation has changed radically since WWII. Back then, for a lot of missions, you basically just needed a flat piece of deck to fly off of. The British put flight decks on some merchant ships, and used them. Nothing else, and it worked OK. Today, that's not going to work at all. Modern aircraft are much more sophisticated, which means higher support requirements. If you want to use them well, you also need good (and expensive) command and control facilities. If I wanted to build a ship with half the fighter capability of a CVN, it would be a lot more than half the size and cost. For instance, let's say I want to be able to keep up one E-2 and two SH-60s at all times. That means I need four and eight onboard respectively, unless I'm willing to sacrifice a major chunk of capability. C3I and maintenance is going to be 90% of a full CVN instead of 50%. And so on and so forth. So now I'm paying 80+% of the full price for half the airframes where I need them. Why is that a good idea?

  5. March 23, 2018RedRover said...

    If I wanted to build a ship with half the fighter capability of a CVN, it would be a lot more than half the size and cost. For instance, let’s say I want to be able to keep up one E-2 and two SH-60s at all times. That means I need four and eight onboard respectively, unless I’m willing to sacrifice a major chunk of capability. C3I and maintenance is going to be 90% of a full CVN instead of 50%. And so on and so forth. So now I’m paying 80+% of the full price for half the airframes where I need them. Why is that a good idea?

    It's probably not, because as you say, the cost of providing half the strike capacity (in terms of bombs on heads) doesn't scale linearly in terms of the back end and support capacity. (By size do you mean tonnage or length? I assume tonnage?)

    What I've picked up from reading here and elsewhere, as well as interacting with you, is that usually things are the way they are for a reason, and the DoD has a lot of smart people thinking about these things. I'm not convinced that they always make the best decisions, for reasons of domestic politics, inertia, and fighting the last war, but it's interesting to see where my thinking falls apart.

  6. March 23, 2018bean said...

    It’s probably not, because as you say, the cost of providing half the strike capacity (in terms of bombs on heads) doesn’t scale linearly in terms of the back end and support capacity.

    Exactly.

    (By size do you mean tonnage or length? I assume tonnage?)

    Either works, although tonnage is the relevant metric here.

    What I’ve picked up from reading here and elsewhere, as well as interacting with you, is that usually things are the way they are for a reason, and the DoD has a lot of smart people thinking about these things.

    This is exactly the thesis I've been trying to get over in my columns on modern procurement and policy. The DoD may be wrong, but it's wrong for a reason. And it's right more often than you'd think.

    I’m not convinced that they always make the best decisions, for reasons of domestic politics, inertia, and fighting the last war, but it’s interesting to see where my thinking falls apart.

    Anyone who tells you that the DoD always makes the best decisions should be referred to Scott Alexander for treatment. But it's usually understandable why they make the decisions they do, and more often than not, they're right.

  7. March 23, 2018Andrew Hunter said...

    It’s a bad idea to berth a squad of Marines three decks and 500 ft of corridor away from their platoon sergeant, but you have no choice. They will get into trouble.

    Uh, are you basically telling me LPA's are set up so NCOs can play RA on the men but CVNs are not? And that marines can't be left unsupervised, while seamen can?

    (I mean, I'd believe it, but just checking.)

  8. March 23, 2018bean said...

    Uh, are you basically telling me LPA’s are set up so NCOs can play RA on the men but CVNs are not?

    Sort of. Keep in mind that your typical junior enlisted is a 19-year-old male. Yes, the NCOs bear more than a passing resemblance to RAs, and naval architects take this into consideration when they're planning berthing and living spaces. But a carrier's designers plan for the typical naval crew, not for a bunch of extra marines, so the marines have to be shoehorned in wherever there's space.

    And that marines can’t be left unsupervised, while seamen can?

    Not exactly. Idle hands are the devil's workshop. Sailors are generally kept pretty busy. Amphibious ships are designed with the facilities to keep marines entertained. Carriers aren't, and it's made worse when the marines are scattered about the ship. It's probably possible to design a dual LPH/CV, and I think the British have done so with the Queen Elizabeth, but it's not what we have now.

  9. March 24, 2018Tony Zbaraschuk said...

    One might also wish to consider new generations of aircraft - a larger carrier can more easily be adapted to a new generation of planes of different sizes. (Not as much of an issue as it was in the 1940's, considering the long procurement cycle, but still an issue.)

  10. March 24, 2018bean said...

    I'm not sure how much weight we should put on that. On one hand, yes. Midway and her sisters were unable to carry F-14s, which was a real limitation before the Hornet showed up. On the other hand, aircraft size seems to have plateaued. That said, a small carrier is a terrible idea, because the cost/capability ratio is much worse than a CVN.

  11. March 25, 2018Inky said...

    Going in another direction, does it makes sense to make LHA bigger and nuclear-powered, but less ships of the same class? Or does the scale factor work differently here?

    On an unrelated note, why does navy need dedicated command ships? Isn't carrier more suitable to this role, and, more importantly, better defended?

  12. March 25, 2018bean said...

    Going in another direction, does it makes sense to make LHA bigger and nuclear-powered, but less ships of the same class? Or does the scale factor work differently here?

    The scaling is different. There's less overhead to the aviation side of amphibious operations. Most of the aircraft are relatively simple, and you don't need the same kind of C3I facilities. And you don't have E-2s or ASW helicopters.

    There's a couple other factors. First, there is a need for numbers. We need about as many LHAs/LHDs as we need carriers, and cutting numbers causes problems there. Second, there is definitely a low-level thought in the USN to make sure that the LHAs are separate from the carriers. I've heard that this was one of the reasons that LHA-8 got a well deck. The conversation we've had here also happens in Congress, and I'd estimate the IQ here is higher. Third, nuclear construction is hard and expensive, and it might be really expensive to expand it to be able to support amphibious ships.

    On an unrelated note, why does navy need dedicated command ships? Isn’t carrier more suitable to this role, and, more importantly, better defended?

    Not really. Modern naval command systems are phenomenally complex, to the point where even a carrier can't accommodate them without penalties. You need lots of space for people and computers, and even carriers aren't infinitely big. Note that the LCCs are mostly kept in port, and not sent out with the fleet, too.

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