From: Alan and Carmel Brain <aebrain@w...>
Date: Thu, 09 Dec 1999 12:38:09 +1000
Subject: Re: [OT]Naval Warfare the case for the BB
Since no-one has complained about the OT-ness, and several people have asked to be CC'd on this thread, I'll continue on the newsgroup. Should anyone object in future, I'll move it to e-mail, and no offense will be taken. My thanks for everyone's indulgence, and I'll make it as On-Topic as I can. > Imre A. Szabo wrote: > I personally don't like Tomahawks on Iowa's specifically because they Minor nit-pick: yes they are, about 6" worth, plus blow-out panels. But that's not much in comparison to the belt. The secondary 5", now they're not armoured. > There have been several capital ships (BB's and BC's) ...and also the newly-fitted Unrotated Projectiles (anti-aircraft rockets) were stored in crates in companionways near the 4" magazine due to lack of space. Exactly what caused the Hood to go Boom is still not clear: I favour an 8" from the Prinz Eugen starting a fire aft of X turret myself, (based on testimony of a neighbour who was one of the 3 survivors), but it could have been a 15". > There was no armor protection there. Um. Yes there was, in the magazine proper. The Ready-Use ammunition was another matter, and this is what you're referring to, right? For lurkers, it's usual for unarmoured guns to have the majority of their ammunition stowed (relatively) safely in the magazines, but a few shells nearby in unarmoured storage that can be used quickly while shells are being laboriously transferred up from the mags. > If you can't protect a highly dangerous item, don't mount it on a BB. Or use blow-out panels. Agree with a minor caveat. > > May I recommend > Sounds, I'll have to check it out. Also wrote excellent books on Submarine design and development, and Naval Radars. Available through the USNI. I've used his books extensively in my professional career. Siegfried Breyer is of course THE authority on German Battleships, and battleships generally come to think of it. > Sure, the carrier can take it where it has armor, but unless your Two separate points here. First, you don't have a lot of choice when it comes to the trajectory of the missiles. Sea Skimmers, unless they "pop up" as in the Otomat or Harpoon 1B model, will hit the side. Period. The "pop up" manouvre was designed to cause more damage, by a steep climb followed by a dive just before inpact, to go through the relatively thin deck armour of most targets and explode in the vitals. It was generally abandoned when it was found that this made the sea-skimmer much easier to hit by the CiWS of the time (ie 23mm and 30mm), and when ships stopped having much side armour. An AS-6 KINGFISH OTOH comes in from 25,000m, at hypersonic speed (FASTER than a 16" by a long way) in an 80' dive. That's nearly vertical. Doesn't matter if you shoot away the white-hot wings etc if you do it at much less than 10,000m, as it's only a few seconds before impact (it slows quite a bit as it hits the thicker atmosphere, but is still going way over 500m/sec) Worst thing is that if you set off the warhead, it will scatter half-tonne chunks of airframe in a shotgun pattern that may well be more damaging than a near-miss in the sea. Should such a beastie hit the side of the ship, one that's well-armoured, it's unlikely that the fuse will go off when it hits, as it's such a glancing blow. It will go off when it hits the water a few milliseconds later though. Same effect as a torpedo hit _not_ under the keel, can easily cause seperation of armour belt from the main structure of the ship, multiple leaks etc, and the shock could break ankles, KO equipment and unseat turrets from their rings. But all in all, far less dangerous than a hit on the deck. Secondly, a note about Deck Armour. Most ships (CVs excluded) have deck armour that's in layers. This is partially for stability reasons, don't want too much weight up too high. But also because of the way plunging fire works. Bombs and shells don't hit very fast. The terminal velocity of a 16" shell is barely above Mach 1, 300 m/sec, and bombs are often only 200 m/sec. This means that, given the way the warheads work, you want to: a) Slow the warhead down so it doesn't go deep (if small) b) Initiate the fuse quick-smart so the hypersonic chunks of ironmongery it will generate don't get too deep. c) Have a secondary layer to catch most of the splinters as soon as possible d) have a tertiary layer that will then stop the remaining large chunks that have gotten through c) That's why in WW2, a typical ship would have: a) A "burster" deck, thick enough to cause fuse initiation b) A "splinter" deck, which would catch the pesky splinters that cut fuel lines, disable electrical systems, kill people etc c) A "main" deck that would maybe catch the football-sized chunks that made it through. This works pretty well vs most warheads. Incendiary warheads, delayed-action warheads, and AP warheads which go through burster and splinter before going off can all defeat it to some degree, but nothing's perfect. In order to physically stop a big warhead (or crashing/landing aircraft), you need a very thick layer indeed. The CVs have this, the BBs don't. And can't because of metacentric height if they're to have adequate armour for the citadel. > The flight decks aren't going to stop plunging fire very well. To You're right, a 16" AP or SAP shell would probably go through, mainly because of the momentum rather than speed. They actually hit quite slowly compared to some hi-diving missiles. > There is no reason why can't have a massive number of mini-attenas the Antennae = EMP vulnerabilities. Call em lightning rods. > > Though only 2 operational, as the relevant magazine would be flooded Not at all. Wait long enough to see that the flames are only coming from the turret, and it's too late if they're not. I know of no ship commander who wouldn't immediately order the flooding of the mag in this case. Usually such orders are superfluous, as the local gun or magazine commander has already done it. Often this means that they die. > For 6 hours the ship won't be able to provide ground support, if the Same as a torpedo hit not under the keel. A bit of a crap shoot. > Use multiple electric propulsars and you don't have the shaft problem. News to me... the only propulsors I know of on large ships are the ones on the FFG-7s (auxiliary steering). They're radically underpowered for the job. AFAIK no ship over 2500 tonnes has propulsors as its main drive. Now pump jets are another matter. The UK "Trafalger" class subs have em, for stealth reasons. I know not about the Seawolf and Centurions. But these are just as susceptible to shock. Also, remember that the USN at one stage used turbo-electric powerplants on some of its Battleships. In this case, the steam turbines drove a dynamo that produced current for electric motors connected to the relatively short shafts. Saved a lot of weight in the Gearbox, a geat success. Until the first battle vs the IJN, where after exactly one shell that didn't even penetrate caused myriads of minor leaks, 100 kv MegaAmp arcs that welded machinery together, melted bus bars, and burnt many sailors. The ship was KO'd for several years, and took months to get back to a place it could be repaired. Had the weather been anything other than unseasonably calm, with many safe anchorages along the way during bad weather, she would have been lost. > If the Bismarck had been a KGV or Iowa, then it would have probably Towed to port from mid-Atlantic during the winter? See below. > > A 100,000 tonne ship in littoral waters that has its propulsion KO'd > With 200 nm guns why would you go closer then 100 nm to the shore if If you're practicing indiscriminate bombardment of an area, you're right. A big gun firing many cheap low-tech shells is a great idea, low risk. The barrel life will be short at this range, but even then you should be able to get 100 shells off between changes, and a new barrel will cost no more than an attack aircraft (and way less than the pilot's training). Of course then there's the cost of the dockyard, the shipwrights, cranes etc. but that's a once-only payment. But if you want the fabled 10m accuracy possible with NGFS under the right circumstances, forget it. And the rounds will take far too long to get to the target anyway if it's moving. Even a 16" at 30,000m - 15 nm - took well over 50 secs from Bang to Boom. Had to, muzzle velocity is about 1000 m/sec, it arrives nearly subsonic (400 m/sec), and has to travel through an arc rather than a straight line. The only reason it takes such little time is that much of the trajectory is in very thin air - it's on the way down it really hits a wall. Of course you can boost the range via Base-bleed and RAP (whichj extend the dwell time at high altitude, so a little goes a very long way). And improve accuracy by having terminal guidance. What was that about "cheap"? Because unlike bombs, these have to take 100g+ accelerations with rates of onset of 10000g/sec. This is quite doable - heck, proximity fuses did this in 1942 - but not cheap OR not reliable. Frankly, the helo or Ground attack aircraft 5 minutes away that can seek its own target sounds a heck of a lot better than a shell 10 minutes away that can't. Unless you can re-target in flight (and possibly get jammed, and what was that about "cheap" again?) > > There's a very good case for a new Monitor, > I said I wanted a modernized BB I suspect we differ less than it appears. I'd go for the Arsenal Ship myself. But that's maybe because I was involved in some of the design study work for it, where all the above was considered. Re NGFS, my