buckland@ucs.ubc.ca (Tony Buckland) (05/22/91)
From: Tony Buckland <buckland@ucs.ubc.ca> In the debate over whether or not Rodney torpedoed Bismarck, I note the side issue emerging of whether surface-ship-launched torpedos did any damage to Bismarck. Are modern torpedos available in a specialized type for this kind of armor-piercing role, in the same way that tanks carry rounds specifically designed to penetrate the armor of other tanks? I realize that the primary role of attack submarines may be to sink other submarines, but I assume it's also envisioned that they may get to do an old-fashioned assault on surface shipping; so, do they have ammunition specialized for this?
phil@brahms.AMD.COM (Phil Ngai) (05/24/91)
From: phil@brahms.AMD.COM (Phil Ngai) Tony Buckland <buckland@ucs.ubc.ca> writes: >In the debate over whether or not Rodney torpedoed Bismarck, I >note the side issue emerging of whether surface-ship-launched >torpedos did any damage to Bismarck. Are modern torpedos >available in a specialized type for this kind of armor-piercing >role, in the same way that tanks carry rounds specifically >designed to penetrate the armor of other tanks? Actually, battleships don't have armored bottoms for a couple of reasons: 1) their designers realize that water carries the force too well for armor to be effective 2) probably battleships stopped being useful around the time that torpedoes became reasonable effective. -- The media is in the business of distorting people's perception of reality, by emphasising the out of the ordinary.
silber@m.cs.uiuc.edu (Ami A. Silberman) (05/24/91)
From: silber@m.cs.uiuc.edu (Ami A. Silberman) buckland@ucs.ubc.ca (Tony Buckland) writes: >In the debate over whether or not Rodney torpedoed Bismarck, I >note the side issue emerging of whether surface-ship-launched >torpedos did any damage to Bismarck. Are modern torpedos >available in a specialized type for this kind of armor-piercing >role, in the same way that tanks carry rounds specifically >designed to penetrate the armor of other tanks? There are torpedoes specialized for anti-submarine and for anti-shipping roles. I'm not sure why they are incapable of being used in a pinch in both roles. (Most of the US surface launched and helicopter launched torpedoes are designed to take out subs, presumably because you really shouldn't get a DD or heli that close to the enemy.) You don't really need armor piercing torpedoes for several reasons. 1) There are exactly four ships that have enough belt armor to worry about. (The US BBs) 2) When firing at surface ships the idea is to have the torpedo explode near the keel, where armor is thinner. Acoustic homing torpedos tend to impact near the screws. 3) If the ship is compartmentalized, with fuel or coal bunkers, you probably won't be able to penetrate the inner hull anyway. 4) Torpedos rely upon the explosion to cause damage. They aren't going fast enough to make a hole before exploding. HEAT rounds won't work because the purpose is not to make a hole (which HEAT rounds against tanks are supposed to do), but to make a big hole. -- ami silberman - janitor of lunacy silber@cs.uiuc.edu
nik@swindon.ingr.com (Nik Simpson) (05/24/91)
From: nik@swindon.ingr.com (Nik Simpson) buckland@ucs.ubc.ca (Tony Buckland) writes: >In the debate over whether or not Rodney torpedoed Bismarck, I >note the side issue emerging of whether surface-ship-launched >torpedos did any damage to Bismarck. Are modern torpedos >available in a specialized type for this kind of armor-piercing >role, in the same way that tanks carry rounds specifically The workings of a torpedo are very different to an armour piercing shell, shells strike armour at very high velocity and are designed to pierce partially by kinetic enery, torpedoes strike at much lower speeds and work by the power of the explosion. Torpedoes are not intended to pierce armour in the way that a shell is. Torpedoes are most effective when they don't strike the armour at all in fact magnetic fused torpedoes do not strike the ship at all the make use of the fact the water is incompressible and hence the shock wave from the explosion is devastating, they are intended under the keel of the ship. -- Nik Simpson Mail : nik@swindon.ingr.com Systems Consultant (UNIX). Intergraph UK Ltd.
henry@zoo.toronto.edu (Henry Spencer) (05/25/91)
From: henry@zoo.toronto.edu (Henry Spencer) >From: phil@brahms.AMD.COM (Phil Ngai) >Actually, battleships don't have armored bottoms for a couple of reasons: >1) their designers realize that water carries the force too well... >2) probably battleships stopped being useful around the time >that torpedoes became reasonable effective. No, battleships were around and effective for quite a while after torpedoes became workable. Destroyers were invented mostly to keep torpedo boats at a properly respectful distance from the battle fleet; battleships didn't really lose out until submarines and aircraft started delivering torpedoes by routes that were difficult to block completely. As I understand it, the major reason for not armoring the bottom is simply that it adds too much weight. Even a battleship can't be armored everywhere. A waterline belt made sense because that was the most vulnerable area against gunfire and shallow-running torpedoes. Internal armored decks protected the engines from gunfire. And of course the command centers and main turrets were very heavily armored. These ate up the weight budget available for armor pretty much completely. One reason why HMS Dreadnought started a revolution in battleship design by deleting all secondary armament in favor of heavier primary armament was that deleting the weight of the secondary guns made it possible to protect the primary ones better. -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry
freeman@ux1.cso.uiuc.edu (Jay Freeman) (05/25/91)
From: freeman@ux1.cso.uiuc.edu (Jay Freeman) phil@brahms.AMD.COM (Phil Ngai) writes: >Actually, battleships don't have armored bottoms for a couple of reasons: [omitted --CDR] Also: when battleships were being built, all torpedoes were surface running. The Iowa class BB's have 12" belt armor at the waterline, which tapers to about 2" at the keel. -- 73 de Jay, WT9S Internet: freeman@ux1.cso.uiuc.edu Packet: wt9s@n9hhi.il.usa.na
wbt@cbema.att.com (William B Thacker) (05/25/91)
From: wbt@cbema.att.com (William B Thacker) Tony Buckland <buckland@ucs.ubc.ca> writes: >In the debate over whether or not Rodney torpedoed Bismarck, I >note the side issue emerging of whether surface-ship-launched >torpedos did any damage to Bismarck. Are modern torpedos >available in a specialized type for this kind of armor-piercing >role, in the same way that tanks carry rounds specifically >designed to penetrate the armor of other tanks? The short answer is that since there are very few heavily-armored ships around these days, such a torpedo wouldn't be needed. The long answer is that it never was. 8-) A torpedo isn't like an antitank weapon, punching a small hole through an armor plate. Neither is a ship like a tank, filled wall to wall with fragile and/or flammable materials. Ships are subdivided, and have damage control capabilities: make a small hole, and either the crew will plug it somehow or they'll seal off the flooding compartment until the hull can be patched and the water pumped out. Anything really vulnerable, like magazines, will be buried deep within the hull, behind many layers of armor, bulkheads, fuel bunkers, and what have you. A HEAT-type warhead would dissipate long before reaching the magazines, and obviously it would be, er, "unfeasible" to create a high-velocity kinetic torpedo. The whole thing is much cruder than this. The torpedo is designed to explode near (not necessarily in contact with, just "near") the ship's hull. The detonation creates a rapidly-expanding bubble of gas, desparately seeking relief from the water constrains it. Relative to water, which is incompressible, an unarmored ship is like putty; and even a fully armored ship is not much more than caulk, or perhaps spacking compound. Even the most heavily armored ships could not afford to cover the entire hull with armor; in fact, the armored belt typically extended only a meter or so beneath the waterline, leaving most of the outer hull unprotected. It would take such thick armor to defeat a torpedo blast that a ship simply couldn't carry it. As testimony to hydraulics, consider that the most devastating bomb hits against battleships in WWII were usually very near misses, which exploded underwater next to the ship's sides, not those actually hitting the ship. Instead, warship designers use other techniques to foil torpedos. I'm not sure about current practice, but the state of the art in WWII featured a "torpedo defense system" along the hull sides, from the waterline down to the flat bottom. This was composed of an outer shell, forming the watertight boundary of the hull, which would detonate the torpedo. Behind this would be void space, the more the better; sometimes these spaces were used for fuel or water storage, but it was better to leave them air-filled and to provide vents at the tops, to provide relief for the explosion gasses. Next came the torpedo bulkhead, typically 1-3 inches thick; hopefully this would contain the blast. In the event that it didn't, more void spaces (or fluid-filled compartments) backed the torpedo bulkhead, and behind them, when possible, was fitted a thin (about 1") armored "splinter bulkhead", whose job was to stop any fragments (in the event that the torpedo bulkhead was pierced) from flying into the ship's internals, punching holes and reducing the watertight integrity. On battleships in particular, multiple bulkheads of this type were common. The gist of the torpedo defense system is to allow the torpedo to expend its energy battering through a series of steel barriers, all the while bleeding off the pressure topside, until not enough energy remained to damage the ship's vitals. The torpedo defense system itself would flood, of course, but this was relatively harmless. Thus the major factor determining the effectiveness of an anti-torpedo system was depth; how much of the ship's beam (width, for landlubbers) can be used for this purpose? This presents a number of immediate conclusions. First, smaller ships will be more vulnerable, because they are less beamy. In fact, cruisers typically carried only a vestigial anti-torpedo system, while destroyers had none. Second, even battleships must sacrifice the torpedo defense system at the bows and stern when the ship narrows; it was not uncommon for battleships to have the bow or stern virtually blown off by a torpedo blast. Finally, it leads us to... ... what do we do about the ship's bottom ? If an explosion occurs there, there's no place to vent the gases except through the ship. The designer's answer, basically, has been to give up. They use double and even triple bottoms to provide some semblence of protection, but in fact torpedo or mine explosions beneath the ship's flat bottom were and probably remain devastating. In WWII, torpedo detonators were unable to reliable produce such an attack, although mines could; today, I'm sure it can be done routinely. The most likely result of such an attack is a broken keel, which means the ship is very likely to break up (although there are cases of good damage control overcoming even this). -- Bill Thacker AT&T Network Systems - Columbus wbt@cbnews.att.com
div3@midway.uchicago.edu (Dwight Divine IV) (05/29/91)
From: div3@midway.uchicago.edu (Dwight Divine IV)
Please excuse any lapses in net etiquette {I'm sure the moderator will
catch the obvious ones anyway :)}, as this is my first time posting to
this newsgroup, although I have enjoyed it greatly over the last 2 years.
On the subject of torpedos and defenses against them, has anyone tried to
develop an active defense? That is, has anyone tried or successfully deployed
an anti-torpedo torpedo or similar device? I know that tricks such as decoys
are used to attempt to mislead incoming torpedos but I wonder if any more
aggressive tactics have been tried. I would think that a torpedo's active
sonar and high-speed propellers would betray its position fairly exactly.
With that in mind, couldn't a small device be launched from the target vessel
to home in on the torpedo (either actively homing on the torpedo's sonar or
screws or being guided to the torpedo by the launching vessel)?
This has been in the back of my mind for some time--along with the similar
question of why submarines don't mount anti-aircraft weapons to be used
against sub-hunting aircraft. I know that a submarine is built never to be
found in the first place, but it seems silly not to try to provide defenses
just in case.
Thanks to all who reply!
Dwight Divine IV
(All standard disclaimers apply, void where prohibited...)002@pnet16.cts.com (J.W.Cupp Lcdr/Usn) (05/30/91)
From: 002@pnet16.cts.com (J.W.Cupp Lcdr/Usn) Some modern torpedoes are classified as "antiship" ... why exactly they receive this label I'm not sure, but I think it's related to warhead weight. Most of the torpedoes not called "antiship" are known as "lightweight" ... this is critical for air delivery by aircraft with limited lift capacity (such as a destroyer-borne helo). Even as far back as WWII, the technology was sought to be exploited to provide torpedoes which detonate _under_ a ship rather than _against the hull_. The key is the expanding gas bubble, explained previously, rising directly under the keel of the target. This was the source of grief early in the U.S. sub attacks...the sophisticated magnetic exploders didn't work, and many startled targets gratefully watched U.S. torpedoes pass completely underneath them without exploding. U.S. forces shifted tactics to hit rather than pass under while improvement were made. Today, we assume the technology is much more mature. Torpedoes which are primarily intended to sink large surface vessels are planned to dentonate under the keel. This (as already stated) is the same principal in use by influence-activated mines, and it is the main reason why mines are so deadly. -- J. W. Cupp UUCP: humu!nctams1!pnet16!002 Naval Telecommunications Center ARPA: humu!nctams!pnet16!002@nosc.mil Pearl Harbor, Hawaii INET: 002@pnet16.cts.com I am solely and personally responsible for the all of the content of the above post. It is all merely my opinion, and not to be construed as anything else.
norton@manta.nosc.mil (LT Scott A. Norton, USN) (05/31/91)
From: norton@manta.nosc.mil (LT Scott A. Norton, USN) Another reason for not armoring the battleship's bottoms: Plunging fire that penetrates the armored deck will then plunge through the bottom relatively harmlessly. (An internal explosion is much more damaging than a 18-inch hole in the bottom.) Scott Norton <norton@NOSC.MIL>
amichiel@rodan.acs.syr.edu (Allen J Michielsen) (06/01/91)
From: amichiel@rodan.acs.syr.edu (Allen J Michielsen) The design of anti-torpedo-torpedo's is a good idea. But there are some problems associated with them. I hope that my thoughts are complete enough that the big picture can be seen without explaining every word and assumption. Look at the following considerations.... 1. A Typical high-(or medium high)-performance torpedo has a speed that is much higher than submarine. Given typical sub speeds are, say, 30 MPH, that gives the torpedo a intercept speed about 60 (and I believe the mark iv is oficially rated at about 52 knots or something like 56 mph). While you can say that the speed of your anti-torpeo-torpedo device isn't important, and this is true as long as the target-sub is in a advantageous position. However, when the target sub is in a advantageous position, they would be able to launch a torpedo at the hostile sub (and would in this case). In this scenario, the planned hostile would be at extremely close range, more about that later. If the target-sub is NOT at a advantageous position, then the recovery or turn around radius and speed of the intercept torpedo is very important. 2. The precision location of ALL underwater homing devices in weapons is NOT terribly good. A small sub is the size of a football field, and quite loud. The torpedo's are much louder, but with a target size approaching 12 ft long, and 15 in dia, moving at 60 MPH, would be nearly impossible to IMPACT with any reliability. After all, +- 50 ft on a football field sized object @30 MPH is nothing compared to +-8 inches on a 1.5x15 ft object @60 MPH. 3. While precision impact would be nearly impossible (see above), it MAY be enough to use a proximity sensor, and explode as close to the torpedo as possible. Water is a terrible damper, using a explosive projectile weapon would be terribly ruined by the damping effect of the water. Short of that, the force required to damage a torpedo is great. Your best chance would depend on being close enough to yourself (the torpedo's target) for the torpedo to be armed, and activate the warhead in a contect charge. Remember that torpedos are loaded on and off subs from cranes on sub tenders, at sea under any conditions. If you saw this once during 'weather' you'd believe in god. They are dropped, banged, and mistreated in every respect. The outside case is about 1/2 in of steel. I would guess that something approaching a small tactical nuclear device would be needed at 50 ft underwater to destroy a torpedo that was NOT armed. Simply using something like that (an explosion) to 'throw' the torpedo off course and depth would be plenty of defense, at long range. When used at short range, it probably would no more effective than countermeasures, and would add a great deal on confusion. Further, is we made one, our enemy would also. The great confusion this would cause, would greatly increase the chance that the torpedo would turn on it's launcher and destroy 'mommy'. With both sides doing this, then,,,, And if we add more smarts so it can identify it's launcher or be disabled by it's lanucher, we add more counter- intelligence to it, more possibilities of more jamming for it, and most importantly, increase both the weight, size, cost of the weapon, and decrease it's max top speed, effectiveness, reliability. 4. Lastly, there is a myriad of social and economic and political reasons. The use of underwater explosive devices kills all the wildlife for a MASSIVE area. Remember also that EVERY launch tube in a sub is a dangerous place. The force from the water at depth is astronomical. Tube numbers are minimized to reduce this potential danger. Using existing tubes would require reallocation of required torpedo tubes. Current subs are built with a limited weapons stock availability and with certain clas weapons in mind. We can't just add another storage area or elevator handling mech for a new weapon. With multiple different platform weapons, getting the desired weapon in the desired tube is almost a feat byitself depending on man and machine. More different possibilities means more potnetial for error and disaster (think of the 16 in gun incident, and don't always believe what the government wants you to think...). Adding more tubes to new subs would require larger subs, causing a whole new list of different problems.... In the future, I can see this becoming more effective, and believe that eventually, there will such weapons. Increased computer speed and decreased size and power requirements, increased/improved sensor&electronics, along with newer higher powered synthetic explosives will eventually make these defensive tools a reality. The problem is that nothing is stagnent. Along with these steps MAY come something like satellite based MAD, DAD, IRAD, UVRAD or NAAD/NAD sensor systems. If/when some or all of these are functioning, then the effectiveness of the offensive use of submarines becomes zero. When this happens, no offensive or defensive submarine will be needed by either side. (In other words, subs cease to be a option for war, so these anti- torpedo-torpedos aren't needed) Of course, this can't happen overnight, and depends on some pretty finely located assumptions. -- Al. Michielsen, Mechanical & Aerospace Engineering, Syracuse University InterNet: amichiel@rodan.acs.syr.edu amichiel@sunrise.acs.syr.edu Bitnet: AMICHIEL@SUNRISE
tek@pram.CS.UCLA.EDU (Ted Kim) (06/01/91)
From: tek@pram.CS.UCLA.EDU (Ted Kim) div3@midway.uchicago.edu (Dwight Divine IV) writes: >On the subject of torpedos and defenses against them, has anyone tried to >develop an active defense? I have been told in WWII, AA machineguns were sometimes fired at incoming shallow-running torpedoes. Also, there are old rumors that the Soviets might use massed RBU barrages as a last ditch torpedo defense. More recently, the USN has a classified research program in "Surface Ship Torpedo Defense". FY91 Authorization for this program amounts to $53.9M with requests for FY92 at $58.4M and FY93 at $34.1M. (All figures from May 91 USNI Proceedings.) Since it is classified, no public statement (at least that I know of) has been made about what approaches are being studied and whether those methods are active or passive or hard or soft kill. But of course, there is speculation, including induced whirlpools to throw the torpedoes off course and 200 knot anti-torpedoes. >This has been in the back of my mind for some time--along with the similar >question of why submarines don't mount anti-aircraft weapons to be used >against sub-hunting aircraft. There are persistant rumors that certain Soviet submarines have small SAMs (variants of SA-N-5 or SA-N-8) launchable from their periscope masts. Apparently, some variant of UK Blowpipe was also offered in a similar configuration. The rumor mill says Israel equipped some of its subs this way. -- Ted Kim Internet: tek@penzance.cs.ucla.edu UCLA Computer Science Department UUCP: ...!{uunet|ucbvax}!cs.ucla.edu!tek
jb7m+@andrew.cmu.edu (Jon C. R. Bennett) (06/02/91)
From: "Jon C. R. Bennett" <jb7m+@andrew.cmu.edu> div3@midway.uchicago.edu (Dwight Divine IV) writes: > This has been in the back of my mind for some time--along with the similar > question of why submarines don't mount anti-aircraft weapons to be used > against sub-hunting aircraft. I know that a submarine is built never to be > found in the first place, but it seems silly not to try to provide defenses > just in case. Some British subs (dont rember which class) mount a Blowpipe anti-aircraft missile launcher in the sail for just such a reason. The launcher (which is about man sized) has 4 missiles and retracts into the sail when the sub is submerged. jon