May 24, 2024

Open Thread 157

It's time once again for our regular Open Thread. Talk about whatever you want, so long as it isn't culture war.

Overhauls are Millennium Challenge 2002, Auxiliaries Part 1, FFG(X), Tomahawk Part 1, Tomahawk Part 2 and for 2023 Drydocks and my review of RTW3.


  1. May 25, 2024muddywaters said...

    Silly idea: it might be rather easy to make a torpedo fly.

    Torpedoes have a lot of power for their size, as being small and fast in a medium as dense as water is difficult. For example, the US Mk14 (1938) weighs ~1.5 tons and produces ~250kW in its high-speed setting. Airplanes have been lifting more weight on less power since they reached that weight in the 1910s, so relatively primitive wings would be sufficient. (For ~100 knots, so they would need to be quite large wings: think Predator, not Tomahawk. Better wings might allow ~150 knots.)

    The propellers would need to be larger than normal to be effective in air. (A normal torpedo propeller in air is not only bad at producing thrust, but has little enough resistance that the engine may overspeed to the point of shedding turbine blades.) The engine water injection (that gives them the name "steam torpedo") comes from an internal tank, not the surrounding water (possibly to avoid having salt in it, possibly because pressurizing the whole system was mechanically simpler than a pump), so would still work out of water. However, lack of cooling might be a problem.

    Larger tail surfaces connected to the existing control system (heading gyro for yaw, pressure sensor for pitch) would work to at least some extent. This part would be easier with a 3-axis control torpedo such as the Japanese Type 91. I think a normal 2-axis system theoretically can be enough to be stable, i.e. to not roll over and crash, but it might be difficult to get right.

    This would not be a practical weapon. Barely enough control to not outright crash is very much not enough control to have a useful level of accuracy. (In particular, the depth/altitude control would be far less precise out of water, so it wouldn't fly into the side of its target like a normal torpedo, but fly at a much greater height then descend when it ran out of fuel, so could miss in two dimensions like a bomb or shell.) The range would be ~10-15km (i.e. less than a shell), and the slow speed would allow it to be dodged or shot down.

  2. May 25, 2024bean said...

    That's an interesting point. I'm pretty sure that the critical issue is going to be cooling, but beyond that, as you mention, there wasn't much reason for it, and I'm pretty sure that a gasoline engine was easier and more powerful, so at this point, we're into reinventing the cruise missile. But reinventing the cruise missile out of a torpedo is hilarious, while reinventing it and calling it a drone and pretending it's new is boring.

  3. May 26, 2024Hugh Fisher said...

    Go for a flying fish design, that alternates underwater and flying phases! It would, uh, skip over torpedo nets? Confuse defensive combat systems: Torpedo! No, missile! No, torpedo! ...

  4. May 26, 2024muddywaters said...

    @bean: Not so much more power as ~30x more range, because torpedoes carried their own air and that seriously reduced their fuel capacity. (A torpedo engine had a turbine but no compressor, which made it easier to construct than a proper gas turbine but incapable of using outside air.)

    And yes, purpose-designed cruise missiles did exist and would have been a better option (though given their lack of use, probably still not a good option: control/accuracy, and vulnerability to AA, would still be issues).

    @Hugh Fisher: there was at least one actual attempt at a missile/torpedo that would have used the same engine in air and water, but it was cancelled.

  5. May 27, 2024EngineOfCreation said...

    Terribly sorry for the multicomment in the other thread, but the comment system here is rather outdated and imho in need of replacement.

  6. May 27, 2024bean said...

    Yeah, that happens occasionally. Not a big deal, and I've fixed the typo.

  7. May 28, 2024Kit said...

    Suppose one put a 30 year old ship up against a new build ship. So that might be a Arleigh Burke Flight II against the Arleigh Burke build today. Or the very first Scorpene submarine vs the newest French Scorpene.

    How would the older ship do? Or suppose it was 2 of the older ships vs 1 of the newer ship?

    You're a fleet designer. Would you rather have 2 of the older ships (not upgraded) or one of the newer ships?

    P.S. There are not many ship classes that have been in production for 30 years!

    P.P.S. I'm super aware this is an open ended question heavily dependent on scads of things.

  8. May 28, 2024muddywaters said...

    That's going to depend on whether "no upgrades" includes "no replacing the aircraft / missiles": a Nimitz with F-14s and A-6s is obviously weaker than the same Nimitz with F/A-18E/Fs. (If your intent is "nothing expensive", it probably should: a carrier's air wing costs ~50% as much as the ship and a full load of missiles for a Burke ~20%.)

    (30-year-old Burkes are Is, not IIs, and Scorpène isn't 30 years old yet. Some others that were in production for 30+ years: Nimitz, and if they count as the same, Kuznetsov/Shandong.)

  9. May 28, 2024Kit said...

    No upgrades. No new missiles or aircraft. As shipped in 1994.

    Now answer the dang question! :-)

  10. May 29, 2024muddywaters said...

    Then I'd expect the newer ship to have a big advantage, both for carriers and for missile ships, but that's very much a guess.

    In particular, I don't know whether who detects who first is mostly determined by sensor quality (strong advantage to the newer ship), physical limits such as the horizon (both detect each other at nearly the same time), or who happens to send their search helicopter to the right place (mostly luck).

    Some of these classes had explicitly anti-ship missiles on the older version and not the newer version, which would help the older ship to some extent, but plausibly not by much. (Current SAMs can be used against surface targets, and while not optimized for that, are plausibly more than enough against 1990s defences.)

    (I'm assuming here that this is a basically normal war and not a surprise drop through a time portal, i.e. both sides (a) are generally alert and (b) know that same class no longer means friendly, so you get a normal battle and not a close-range surprise, but (c) don't know to expect an opponent like themselves and not e.g. a submarine, so don't get to optimize their missile loadout or search protocol for that.)

  11. May 30, 2024bean said...

    Hmmm. I might try this out in CMO. I think I'd put my money on the new one, but not by a huge amount.

  12. May 30, 2024Kit said...

    I've also been thinking about 50 year old ships. Back then all they had was semi-active radar homing missiles, so the number of targets you could target waaaas limited to the number of illuminators you had. Which was often 2. TWO.

    So you could target 2 things at once. What was the plan? Didn't they envision a large pile of incoming bombers/missiles things?

    I understand why they had this limitation (because 1970s technology). But how did they understand the battle would happen? And did they have any technique so that multiple ships in a fleet could coordinate their targetting (i.e. spreadit around)?

    Given this type of equipment, and a competent enemy, how do you win?

  13. May 31, 2024Kit said...

    I did find this page, which was super helpful. Now I'm sure the 1974 boats are doomed!

    I'm still interested in what people think.

  14. May 31, 2024bean said...

    What was the plan? Didn’t they envision a large pile of incoming bombers/missiles things?

    Usually, yes, but there really wasn't an option, and some long-range air defense is better than none. (Also note that work on concepts for dealing with saturation started almost as soon as the 3T was in service, but it took a long time to get to the fleet for various reasons.)

    But how did they understand the battle would happen?

    Hopefully, the fleet's fighters would take care of a lot of the incoming bombers, and the SAMs would only have to deal with leakers.

    And did they have any technique so that multiple ships in a fleet could coordinate their targetting (i.e. spreadit around)?

    Yes. Link 11/NTDS, which I've written up under the ICNW tag.

  15. May 31, 2024bean said...

    Right. Two 1994 DDG-51s vs one 2024 DDG 125. Ships were set up about 70 nm apart, and sent towards each other, then told to shoot at each other. I am letting the AI handle the actual fighting.

    The old ships got off the first salvo with their Harpoons, although this might have been because I had it set up to not use SAMs in surface-to-surface mode until after they'd launched. When I made that switch, Lucas fired off SM-6s immediately. For reasons I can't understand, Lucas didn't shoot down many of the Harpoons and took a reasonable amount of damage (seriously, there were loads of ESSMs still in the VLS, although her EW suite lured a lot of them off) but she won the day, as the older ships had poor ECM and no answer to the SM-6s.

    I then tried a second time, setting DDG-125 to fire manually at the Harpoons, and got the clean sweep you'd expect. I also looked at what was going on with the older ships, and the problem is that pre-ESSM, they don't really have a good answer for short-range shots from something as fast as SM-6. It looks like SM-6 is too close for the SM-2s to engage by the time the OODA loop runs.

    In this particular case at least, clear win for the newer ship.

  16. June 01, 2024Kit said...

    you're my hero! Thanks

  17. June 01, 2024Neal said...

    I wonder what his excuse/defense is? Seems as if Admiral Burke is in a bit of trouble.

  18. June 01, 2024muddywaters said...

    That makes sense: taking too long to react to missiles (or airplanes) was a very real problem for older SAM systems. (The 1991 first "successful" interception was on a missile that had already missed the ship it was aimed at, though it does still make sense to destroy such missiles as a potential hazard to ships further away.)

    (They also might malfunction or simply miss even if they did react in time. However, the alternatives were guns (probably even worse) or nothing. As already noted, a defence doesn't have to be perfect to be worth having: using more missiles costs resources the enemy might not have.)

  19. June 01, 2024bean said...

    I wonder what his excuse/defense is? Seems as if Admiral Burke is in a bit of trouble.

    If recent events are anything to go by, "NCIS framed me" is looking pretty good.

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