May 01, 2020

Open Thread 51

It's once again time for our Open Thread. Talk about whatever you want, even if it's not military/naval related.

I have another documentary recommendation, How to Command a Nuclear Submarine on Amazon Prime. This is a look at the RN's famous Perisher submarine command course, widely known for its difficulty. Four RN and one USN officers are evaluated at the helm of HMS Triumph in a variety of exercises. Overall, it's well-done, although there's nothing groundbreaking in it. It's also narrated by Peter Capaldi, better known as the Twelfth Doctor, which occasionally resulted in me getting confused over what show I was watching.

2018 overhauls are British Battleships in WWII, two more of Jim Pobog's sea stories, the first three parts on main guns, Life Aboard Iowa, and the first part of So You Want to Build a Modern Navy. For 2019, we have my Easter post on the four chaplains, Continuous At Sea Deterrent, the review of Polly Woodside, So You Want to Build a Battleship - Construction Part 3 and Shells Part 3.


  1. May 01, 2020cassander said...

    So in shocking news, it seems like the USN has actually made a reasonable procurement decision and gone with the FREMM design for FFG(X). I remain deeply skeptical of our ability to get them built for less than half the cost of a burke and would prefer a design with more VLS tubes, but of the options on the table this seemed to be the best bet. Anyone else have thoughts?

  2. May 01, 2020bean said...

    My theory is that they hit maximum possible wrongness with the LCS and Zumwalt, so the only place left to go was a sensible decision.

  3. May 01, 2020quanticle said...

    The Wall Street Journal has an article (archive/un-paywalled version) on some of the naval architecture challenges that Carnival faced in building its latest cruise ship, the Mardi Gras.

    I find the design of cruise ships interesting, even though they're the ugliest things afloat, simply because there are so many constraints that have to be satisfied in order to make one successfully.

  4. May 01, 2020bean said...

    Very interesting. The architecture of cruise ships is fascinating, in that they're dealing with problems that you never see anywhere else. I do like to read about them. That said, the comments about growth seem rather ironic given what's happened since then.

  5. May 02, 2020quanticle said...

    The other bit of irony is that even though the ship is named Mardi Gras, it's too large to fit into the port at New Orleans. Whoops.

  6. May 02, 2020echo said...

    I'm a bit confused how the frigates will be cheaper if they have all the same Really Expensive Bits as a Burke. They want a "fleet frigate" that's also cheap enough to "defend convoy ships" (from what? Somali pirates? Iranian air strikes on tankers? A Chinese Bismarck-copy?)

    Isn't this just building a general purpose destroyer and calling it a frigate?

    For most of the missions it sounds like a Legend-class coast guard cutter would work. Although they're also weirdly expensive given their limited capabilities, they're 2/3rds the price not including the x-hundred million in govt-provided Aegis.

  7. May 02, 2020bean said...

    It doesn't necessarily have the same Really Expensive Bits. Yes, it has Aegis, but it's not the same system as the Burkes do. The computers and software are cheap, and the radar and such are different (and presumably cheaper) systems.

  8. May 03, 2020AlexT said...

    “defend convoy ships” from what?

    AIUI, the worst-case assumption (from a naval view point) is a peer-competitor war that doesn't go nuclear. In that case, merchant (and military) traffic will get hit by subs and long-range aircraft. An AEGIS frigate sounds just about right.

  9. May 03, 2020John Schilling said...

    The Block 0 version may be cheaper than a Burke, but I'm skeptical that it will long remain so - there's going to be a lot of pressure to say that our frigate sailors shouldn't get "second rate" ships, and that adding just this one extra capability from the Aegis/Burke menu. Enough iterations, and we're paying 80% of list price for a Burke with half the VLS cells.

    I'd have preferred a "No SPY-1, no Standard missiles, best Evolved Sea Sparrow system you can fit" requirement, and I'd have preferred using that displacement for two full helicopters plus the drones. Instead, I'm stuck hoping they can do better than I have any reason to expect on cost control for this.

  10. May 03, 2020Jade Nekotenshi said...

    I'd argue that yes, this frigate is pretty much a general-purpose destroyer. It's not called a destroyer for the same reason we don't call Flight IIa Burkes cruisers.

    That said, I would have liked to see a non-Aegis version instead. But for now it might be necessary to retain SM-6 capability if only for anti-surface pinch-hitting. Sure, a carrier group would use fighters, but a convoy escort might have a use for something that can cripple a frigate or a surfaced submarine.

  11. May 03, 2020cassander said...

    @john Schilling

    That was my original desire. No big area air defense radar (which is expensive) but a large missile capacity (which is cheap) and the links to let them serve as mini-arsenal ships to nearby burkes, plus lots of space for helos and expansion. That lets them contribute meaningfully and efficiently in both high and low threat environments. But the USN was never going to make that choice.

  12. May 03, 2020Neal said...

    Thanks for that recommendation on the sub documentary Bean. As with so many of these programs the narration is borderline annoyingly overwrought, but I give Capaldi a pass on this as I thought he made a good Doctor and he is known, as an actor, for not taking himself too seriously.

  13. May 04, 2020quanticle said...

    I’d have preferred a “No SPY-1, no Standard missiles, best Evolved Sea Sparrow system you can fit” requirement, and I’d have preferred using that displacement for two full helicopters plus the drones.

    Isn't that what the Littoral Combat Ship was ideally supposed to be? Of course, in reality they tried to make it this modular... thing that really couldn't do any of its assigned tasks well, but I vaguely remember the original concept being a light attack ship that could land special forces and small groups of marines via helicopter and support them in shallow water operations.

  14. May 04, 2020bean said...

    FFG(X) doesn't have SPY-1. These days, other radars give enough performance for Aegis, and it's got something else. As for Standard, that probably comes more or less free, given that they probably have strike-length VLS tubes. AFAIK, all navies that have ESSM-only Aegis ships don't operate Standard.


    The LCS concept was a terrible muddle. Nobody is quite sure what the point was.

  15. May 04, 2020Alexander said...

    I think the LCS 'mothership' idea makes sense, but making it fast enough to race fast attack craft isn't compatible with doing that well. A slower and larger ship could have been cheaper and more capable.

  16. May 11, 2020Commenter said...

    @bean, quanticle, and Alexander:

    First off, hi guys, first time commenter, found the blog not along ago from SSC, and wanted to add some thoughs about LCS.

    From the perspective of the Fleet, starting in the early 00s, it was obvious (although probably never explicitly said, certainly never written down) that the projected environment for LCS was going to be the Persian/Arabian Gulf. The emphasis on FAC/FIAC capability, MIW, and shallow-water ASW (along with the idea of rapid change-out of modules in secure shore-side facilities) begged the question of who fit that threat pattern, with the answer being "Iran", for the most part.*

    Of course, LCS was always building upon previous concepts (eg Streetfighter/Arsenal Ship), and had a large dose of Rumsfeldian "Revolutionary, not Evolutionary" mantra thrown in. Unfortunately, they never could pull off the down-select to narrow down the classes due to someone losing (and thus you have two orphan ships), along with legal problems/lawsuits that would have come from the losing company, so they just continued to acquire more of them (partially because there were already open production lines, and partially domestic politics). Now we have a bunch of them, and we'll figure out what to do with them later.

    However, while they definitely were pitched as replacing the command opportunities of the departed Oliver Hazard Perry FFGs, and taking on the missions the FFGs were doing by the mid-00s, they were never intended for anything like an open-ocean ASW escort that the OHPs were built for. We've tried to use it for various things, since, again, we have it and we can't get rid of it. It might end up being a fairly useful colonial gunboat for showing the flag/TSC and related missions, and useful in less-intensive or threatening areas of operation, but that will be it for awhile.

    Anyway, sorry for the long first post!

    *-given that's what it seemed to be designed for, it's interesting that it's never even been talked about as going to that fleet area.

  17. May 11, 2020bean said...

    No worries about that being long. I'm definitely in favor of detail, as you might have guessed. A lot of the reason I rounded off to "muddle" was because I didn't want to go into that much detail.

  18. May 12, 2020quanticle said...

    I did a bit more reading about the Oliver Hazard Perry-class frigates, and now I have a somewhat better understanding about the relationship between the OHP class, the Littoral Combat Ship, and this new class of frigates that the US Navy is buying.

    From what I've read, it looks like the LCS was supposed to have a swappable mission pack that would allow it to take over the fleet escort role that the OHP class was fulfilling. Indeed, the rationale behind the retirement of the OHP class was that the LCS was coming and that soon we would have a single small ship that could handle:

    • Anti-submarine escort
    • Special forces transport
    • Minesweeping
    • General anti-piracy efforts ("colonial gunboat" to use a term from a different era)

    As it turns out, the LCS wasn't really good at any of these things, and meanwhile, the OHP-class frigates had been mothballed (and, in many cases, actually sent to the scrapyard). Now, the US Navy was looking at a hole in its capabilities, especially given that it was refocusing towards the Indo-Pacific and was going up against forces that could sortie more capable platforms than the outdated destroyers and fast-attack boats that Iran could sortie.

    Given that there isn't really the time, budget or appetite to design yet another new small surface combatant (after the Zumwalt-class and LCS disasters) the US Navy is buying and customizing a decent off-the-shelf frigate, the FREMM. Like cassander, I also have my doubts about whether they'll be able to keep costs down, but who knows? After all, the Virginia-class submarines turned out quite nicely. There's hope yet.

  19. May 12, 2020Suvorov said...

    I was watching a video the other day about railguns, as one does, and it was discussing the Navy's ideal requirements for a railgun system – which obviously haven't been met yet – but included a range of 100+ miles and a barrel life of 1000 rounds.

    That made me think, because it seems to me if you have a 100+ mile range, you're looking at something close to an anti-ship missile system, and you should be happy to take a barrel life of 200 rounds. Sure, it'll drive costs up, but not as much as 200 supersonic anti-ship missiles.

    But then I got to thinking about how many shells you'd need to shoot to get one on target – presumably you could detect and try to dodge incoming rounds, and even if they were traveling at hypersonic speeds, you could start maneuvering when you thought they might be firing at you. I don't really know what the "conversion rate" if you will, between a railgun (or a 5 inch gun) and missiles is – they're pretty dissimilar. How should I be thinking about this? Setting aside the detection problem, is a good railgun going to be killing a destroyer every other shot, or are we looking at a world where railgun-battleships steam around for two hours shooting at each other to little effect?

  20. May 12, 2020quanticle said...

    The other question w.r.t. railguns is the damage that railgun shells do. Is the kinetic + explosive payload of a railgun round similar to that of an anti-ship missile, or will a railgun require more hits to inflict the same amount of damage as, say, a Harpoon?

  21. May 12, 2020bean said...

    First, the railguns are being looked at for land-attack missions more than anti-ship missions (primarily a matter of guidance), so you want a longer barrel life for that.

    Second, the projectiles are pretty small. Not tiny, but IIRC the lethality is more in line with a 6-8" gun than a big ASM. Muzzle energy is on the order of 20-30 lbs of TNT. Energy on impact will be somewhat less. Details of the damage will depend on the exact mechanics of impact, but I'd guess that you're looking at half a dozen or so hits to take a standard destroyer/frigate out of action.

  22. May 12, 2020bean said...

    On accuracy, I don't hold out much hope for it at long ranges. Even if we ignore deliberate maneuver, there's lots of room for error in things that are hard to quantify. Let's say that you're shooting at an FFG(X) (picked because I had the tab open) doing 20 kts, and you get the course wrong by 1 deg. If it takes 55 seconds for the projectile to get there, then a shell that would have hit the centerline of the ship will now impact the outer edge of the hull. That's a fairly small course error, and a lot less than the flight time to maximum range. It would be trivial to fit all ships with a device to make them subtly zig-zag across a couple degrees (they actually did this during WWII to counter submarines), making them much harder to hit with unguided projectiles while not really affecting them in general. In WWII, they dealt with this by firing lots of shells in patterns, but that would require a very different architecture if using railguns.

  23. May 12, 2020Alexander said...

    Guided shells exist - perhaps it would be possible to build one capable of being fired from a railgun and fitted with some sort of seeker (GPS wouldn't be much use against a warship)? I suppose if you put ASMs at one end of the cost spectrum, and unguided shells at the other, a seeking railgun projectile could fall in between.

  24. May 12, 2020Suvorov said...

    Details of the damage will depend on the exact mechanics of impact, but I’d guess that you’re looking at half a dozen or so hits to take a standard destroyer/frigate out of action.

    So, 200 railgun rounds = 40 antiship missiles worth of damage...

    On accuracy, I don’t hold out much hope for it at long ranges.

    ...and maybe half a dozen worth of accuracy? Definitely not, as you say, worth much as an anti-ship weapon, at least not at anti-ship-missile ranges.

    Guided shells exist - perhaps it would be possible to build one capable of being fired from a railgun

    My guess is that it would be more difficult to build a sensor that withstands the heat/acceleration of a railgun than a conventional weapon, since the shell is accelerating faster (probably) and the heat build-up would be spread pretty evenly along the length of the round.

    and fitted with some sort of seeker (GPS wouldn’t be much use against a warship)?

    Maybe radar or radiation homing? I would imagine that the heat of launch and the skin friction/possible inclement weather would be pretty bad for an imaging IR sensor.

  25. May 12, 2020quanticle said...

    My guess is that it would be more difficult to build a sensor that withstands the heat/acceleration of a railgun than a conventional weapon

    Don't forget that the sensor needs electromagnetic shielding as well. The amount of electric current needed to accelerate the projectile (and the strength of the magnetic field it generates) will play merry havoc with any kind of electronics that are exposed on the outside of the projectile.

  26. May 12, 2020bean said...

    You've pretty much worked out the sensor issues the system would face yourselves. You've got limited weight, limited space, limited time, and a lot of Gs. This is not a good combination. Passive radar is the only option I can see that might work, but even that is tricky in a 30-lb projectile that needs to withstand railgun launch.

  27. May 13, 2020Alexander said...

    I hadn't considered the current, and I suppose that's something that existing projectiles don't face. I'd think that high accelerations, velocities and limited space are problems that have already been encountered, though perhaps not all together, or to the extent that a railgun shell would experience. If you couldn't produce any sort of guided railgun ammunition, would they have sufficient advantages over a conventional 5" to outweigh being unable to fire GPS or Laser guided shells?

  28. May 13, 2020AlexT said...

    Don’t forget that the sensor needs electromagnetic shielding as well.

    Couldn't the sensor be located ahead of the conducting portion of the projectile, so it'd be spared the current and most of the EM? Maybe in a fully isolated enclosure that opens or ablates away quickly after launch? Of course, this doesn't help against acceleration, but guided artillery projectiles do exist, so I guess it's not a showstopper, theoretically.

    What I can't understand is how this is superior to a rocket-assisted chemically-propelled round, which would seem to require far less groundbreaking progress. Or is it simply that, if you're going to put high-quality guidance, sensors and propulsion on a round, you might as well give it a serious rocket engine and call it Standard?

  29. May 13, 2020bean said...

    The majority of guided artillery projectiles are GPS guided, and the exceptions I'm aware of are laser-guided. There's a reason for this. These are the types which are easy to make small, light and cheap. Unfortunately, GPS-only is right out for anti-ship railgun projectiles, although it's the system of choice for current railgun studies (which tells us what the planned role is). Laser is somewhat better for maritime targets, but you still need a designator, which isn't always the easiest to arrange when shooting at a hostile warship. Current railgun projectile designs are GPS-guided. And while modern electronics have made other options at least somewhat viable (SDB-II springs to mind) I don't know of any that have made it into artillery shells. And frankly, a railgun is smaller and a tougher environment due to the size, speed, and EM constraints.

    What I can’t understand is how this is superior to a rocket-assisted chemically-propelled round, which would seem to require far less groundbreaking progress.

    You don't need any form of chemical propellant, which saves cost, size and weight. Dealing with energetic chemicals is complicated, expensive, and tricky. With a railgun, you have no need for any of that, so each shot can be cheaper and you can fit a lot more in the magazine.

  30. May 13, 2020AlexT said...

    Thanks, makes sense. So there's little chance of railguns shooting at ships or tanks, much less planes or ballistic missiles (or enemy railgun rounds) in the near-ish future.

    But then, are they really that much better/simpler/cheaper than RAPs, to warrant development of specialized ships to mount them? AIUI, only Zumwalts have enough onboard power for sustained firing.

  31. May 13, 2020bean said...

    Not exactly. Tanks are easy to hit if they're' stationary, which is the case most of the time. And the problem with shooting at ships is that at long range, there's lots of time for errors to build up. But the key there is "at long range". If you're able to actually see the target, the problems go way down and this becomes a viable weapon against moving targets. Ships, yes, but also potentially airplanes (if the target is only seconds away, their ability to maneuver is limited) and even ballistic missiles. Those are actually surprisingly easy to hit, because they don't maneuver, and they're high enough to be easy to see, too.

    As for power, it's a matter of needing to develop the systems for the future, not for today. There have been efforts to get Integrated Electric propulsion on the Flight III Burkes, although they seem to have failed. Whatever follows them definitely will have that.

  32. May 13, 2020redRover said...

    Re the rail gun, does it allow for more uniform acceleration than a traditional gun?

    Obviously it's not going to generate light accelerations the way a rocket or a bomb would, but I wonder if it can generate a more linear acceleration curve than a traditional gunpowder driven projectile. IIRC, from your past writing the incremental benefit of longer barrels is somewhat more velocity, but it's not at all linear, suggesting that projectiles experience peak acceleration over a fairly short distance in the first few calibers.

  33. May 13, 2020bean said...

    I think it does. Yes, guns often are limited by what you can do with powder (a topic I intend to go into more detail on at some point soon) which a railgun doesn't have. I'd guess that you're going to see some dropoff as the projectile moves down the barrel, but it's been a long time since I did railgun physics, so I can't be sure.

  34. May 13, 2020Alexander said...

    What sort of shell sizes are being considered for railgun projectiles? Would the ammunition be particularly lacking capacity, compared to conventional naval guns?

  35. May 13, 2020Lambert said...

    You can't exactly stack up sizes of explosive shells vs railgun projectiles next to each other, since at mach 8 or so, an object has as much energy as the same mass of TNT.

    How fast does a thing have to go before the heating begins to ionise the air it hits? Any plasma around the projectile would interfere with radar guidance or radio control.

  36. May 13, 2020bean said...

    As Lambert says, you're going to have kinetic energy in the projectile that almost equals its weight in TNT. This is great for poking holes in things, but somewhat less effective at area damage. AIUI, the plan for that is to fragment the shell shortly before impact, spreading out the damage. So you're not too worried about capacity. The values I've seen for shell weight are in the 30-40 lb range.


    I can't recall the plasma threshold offhand, but this feels borderline.

  37. May 13, 2020Lambert said...

    Wait, will Whipple shields start turning up everywhere as a counter? I suppose spaced armour is already a thing but it'll be much more of a problem when you don't get to fuse the projectile to blow up after it's gone through the outer layer.

  38. May 14, 2020Alexander said...

    I assume a proximity fuse would still be an option? Or would we be going back to time fuses for fragmentation?

  39. May 14, 2020AlexT said...

    If you’re able to actually see the target, the problems go way down and this becomes a viable weapon against moving targets.

    Even at longer range, against a ship, the target needs to maneuver to dodge. So they need to direct power to the propellers, instead of their own railguns. And they would need to perform evasive maneuvers, with lots of turning, instead of actually going somewhere. Suppressing fire, as it were.

    Other railguns should be able to act as point defense. If the round is shot to pieces, the fragments would aerobrake even if they're on the right trajectory. Maybe a low(ish)-velocity guided round for point defense, since half the velocity means 4x the rate of fire for the same power consumption, as well as an easier ride for sensitive electronics.

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