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Monday, June 10, 2024

Deadly Fish

Gotta get closer to shore, the Captain thought.  They were already dangerously, recklessly close with only a few feet of water under the keel but safety – and surprise – lay to the starboard, landward side of the ship, not the open ocean to port even though every sailor’s instinct told him to veer off and make for open water. 
 
A few whispered commands and more than a few discrete, disbelieving looks from the immediate crew and the ship inched closer to shore.
 
If any ship could carry out this mission, the Captain knew, it was this one.  The ship was a Fletcher II class destroyer – a true destroyer, not some unholy, underarmed, unarmored, cruiser size ship that was designated a destroyer to keep Congress from asking inconvenient questions.  This was a ship built to fight and kill.  The ship was designed with maximum radar, IR, and acoustic stealth to be as nearly invisible as was possible.  It mounted four 5” guns, dozens of CIWS and SeaRAM mounts, and a main battery of 10x 650 mm torpedoes in two quintuple, centerline, rapid reload launchers, one midships and one nearer the stern to provide separation in the event of battle damage.
 
Right now, the ship, and her five squadron mates were on their way to knock out the southern Chinese invasion fleet that, along with a middle and northern fleet, had been attacking Taiwan at three separate sites for the last five weeks.  The Taiwan forces had managed to absorb the initial assaults at great cost but were losing as the Chinese continued to pour reserve forces and supplies into the assaults.  Something had to give.
 
The preferred method of attack against the invasion fleet had been the anti-ship cruise missile but US stocks (and Chinese stocks!) had been quickly depleted in the first three weeks and had proven largely ineffective against the Chinese version of Aegis.  The US had believed in the effectiveness of their own Aegis system so it should have come as no surprise to US planners that the Chinese version (copied and improved from Aegis) would also be effective.  Yes, there had been several Chinese ships of various types sunk or knocked out of the fight but the Chinese pre-war numerical advantage and close proximity to the assault had allowed them to absorb the hits with almost no operational impact.
 
The US had targeted the amphibious and supply ships which, in hindsight, had been a mistake as it exposed the attacking cruise missiles to the full depth of the escort’s protective anti-air defensive layer.  Relatively few of the thousands of missiles launched over the weeks had gotten through.  The Navy’s Tomahawk Block V, while lauded by Navy leadership pre-war, was still, essentially, 1980’s technology with a few added enhancements mostly related to networking and remote communications which had no actual combat value.  It was, for all practical purposes, the 1980’s Tomahawk Anti-Ship Missile (TASM).  While the range was impressive at 1000 miles, the missile lacked the supersonic speed, terminal maneuverability, and on-board countermeasures to successfully penetrate the Chinese Aegis defenses.  Range without lethality was pointless, as the Navy had found out the hard way.
 
The Navy’s air-launched Long Range Anti-Ship Missile (LRASM) had had greater success but the Navy had unwisely cancelled production in anticipation of a Next Generation LRASM (NG-LRASM) and, thus, inventories were very small and the missiles were depleted in the first two weeks.
 
Thus, it was that the Fletcher II class squadron found itself skimming the southern shore of Taiwan, literally hugging the coast to blend their already minimal radar signatures with the returns from the land as they proceeded single file at 30+ knots with just 50 m bow to stern separation between ships.  This was insane sailing by any peacetime standard but was now the preferred tactic for this mission.  Only by getting lost in the land’s radar and acoustic clutter could the ships hope to survive long enough to reach their launch point.
 
The destroyers had broken off from escorting a resupply convoy as it pulled into Hualien during the early evening as darkness was descending.  Hualien was a major port on the central, east coast which was protected by mountains and had become a natural convoy destination.  It was 170 miles from Hualien to the southern tip of Taiwan – around five and a half hours sailing at the destroyer’s best speed.  The Chinese had seen convoys come (some badly battered, some largely untouched) and go from Hualien repeatedly and one more convoy went unremarked by Chinese infiltrators watching from the heights.  The appearance or disappearance of a handful of escort destroyers didn’t attract the attention of the Chinese army infiltrators who didn’t really know or care about naval matters.  The destroyers were just ships going about their convoy escort duties as they had done dozens of times before. 
 
Map of Taiwan
 

Now, the destroyer squadron rounded the southern tip of the island, just seventy or so miles to the Chinese invasion fleet.  Another five miles and the squadron reached the launch point.  Every additional mile from this point on significantly increased the risk of detection.
 
One after another, the destroyers pivoted away from the shore to unmask their centerline torpedo launchers and began the launch, rapid reload, launch cycle.  Each ship carried 40 torpedoes and the squadron launched a total of 240 torpedoes in under ten minutes before reversing course to had back the way they had come, their mission complete.
 
Southern Tip of Taiwan


As the wave of torpedoes approached the invasion fleet at their 30 kt cruising speed, they stayed near the shore where the surf noise helped mask their motor noise.  At around five miles, however, the torpedoes spread out along a ten mile front perpendicular to the shore.  This set up a ten mile wide sweep through the invasion fleet’s location.
 
At this point, the outlying fleet escorts began to pick up the acoustic signatures of the approaching torpedoes and, after a few more minutes of indecisiveness, confirmed the detection of the torpedoes and sounded the alarm.  The ships that were moving began to turn away and scatter to the north while those that were stopped or anchored began, frantically, to get underway.  Ironically, the initial reaction of the outer ships, which was to turn away from the threat, wound up bringing them closer to the main amphibious fleet and had the effect of concentrating the targets for the torpedoes.
 
With so little warning, there was no hope of escape as the torpedoes accelerated to their terminal attack speed of 60 kts.  The torpedoes began sensing individual targets and their simplistic programming resulted in them locking onto the nearest valid target, often multiple torpedoes per target.  The torpedo designers had purposely omitted any attempt at sophisticated target discrimination, acoustic imaging, networked smart allocation of targets, or any other worthless action that contributed nothing but cost to the torpedo.  These torpedoes were ‘dumb’.  They would go after the first target they saw that met some basic criteria.  This meant inefficient allocation of weapons but the designers realized that the solution to that was numbers.  If you could put enough weapons in the water, it didn’t matter how inefficient they were.  These torpedoes were the equivalent of area bombardment.  They would attack any target and amongst a Chinese invasion fleet, any target was a good target.
 
The Chinese ships frantically fled, twisting and turning to avoid the incoming torpedoes.  There were a few collisions and many near misses but, ultimately, it did no good.  A ship might evade one torpedo but the seeming endless wave of torpedoes ensured that another torpedo would lock on.  The first torpedoes began impacting and explosions and fires began dotting the sea.  The wave of torpedoes continued on.  Inevitably, by pure chance, some ships escaped being targeted and survived but the southern flank of the invasion fleet was devastated and disrupted.
 
The wave front of torpedoes continued on, passing through the escorts and impacting the largely motionless amphibious ships.  Ship after ship took hits, ripping the guts out of the invasion.  By the time the torpedoes passed through the center of the fleet and began approaching the northern escorts, there were few torpedoes left but even those few managed to completely disrupt the escorts, causing them to flee further north.
 
With the Chinese invasion fleet broken and the carefully networked Aegis-like air defense completely disrupted, a carefully timed B-2/21 bomber force, heavily supported by electronic warfare aircraft and led by an F-22 fighter sweep, hit the surviving ships of the invasion fleet with a barrage of various close range air dropped weapons.  This kind of close attack couldn’t have succeeded if the escort force was still intact, networked, and integrated.  The destroyers, however, had seen to that threat.  As the bombers and fighters pulled off their attack and headed home, the Chinese southern invasion fleet had, for all practical purposes, ceased to exist, providing some badly needed relief to the Taiwan defenders and allowing the defensive forces to concentrate on the middle and northern invasion sites.
 
 
 
 
_______________________
 
The Torpedo

Don’t believe the torpedo described in the story could exist?  Consider these range specifications for real torpedoes.
 
 
US Mk48 Torpedo
Range: 
38 km (24 mi; 21 nmi) at 55 kts
50 km (31 mi; 27 nmi) at 40 kts
 
Type 65 Soviet 650 mm Torpedo
Range:
50 km (31 miles) at 50 kts
100 km (62 miles) at 30 kts
 
Is it that big a leap to believe the torpedo described in this story could exist?
 
Story Torpedo
Range: 
137 km (85 miles; 74 nmi) at 30 kts with 60 kt terminal attack speed
 

 
Story Aspects
 
This story demonstrates, among several other things, the value of a very basic weapon.  The imagined torpedoes have been designed with none of the wire guidance, multi-mode seeker, acoustic imaging, etc. that drives up cost, consumes internal volume, increases production complexity which decreases production rates, requires complex software, and adds little combat capability improvements.  Thus, the internal volume savings can be devoted to additional fuel and/or a larger warhead.
 
Simpler, easier to produce, cheaper, and just as lethal – what’s not to like?

  
The story also demonstrates the value of an optimized, specialized weapon system, the destroyer, whose sole primary purpose was anti-surface/torpedo.  A multi-function ship with just a few torpedoes could never hope to achieve the kind of wholesale, efficient destruction described in this story.  The entire navy wouldn’t be composed of these ships, of course.  It would just be one or two squadrons worth.  The rest of the fleet would be a mix of various other ships, each with their own specialization.  This gives the operation planner a menu of specialized ships to choose from instead of being forced to use just one ship type which isn’t optimized for any one function (hi, Burke!).
 
 
Yet another aspect of the story is that it Illustrates the profligate expenditure of weapons (many readers will be shocked by the number of torpedoes used, having completely forgotten what real missions require in a true war) which is  characteristic of every real war in history and totally absent from every pre-war plan in history.
 
 
Missions
 
Additional mission examples for a torpedo destroyer might include:
 
  • Sinking merchant ships in a blockade scenario, something that the current Navy surface ships would have a very difficult time doing.
  • Launching specialized recon torpedoes (USV) for recon of harbors, shorelines, chokepoint passages, etc.
  • Land attack using torpedoes with suitable fuzing against docks, dry docks, shoreline facilities, etc.
  • Destruction of causeways being used to unload ships
  • Anti-ship attack from over the horizon using with the aid of spotter UAVs
  • Convoy escort
 
 
Fun Facts:
 
From Wiki:
  • The torpedo inventory of the U.S. Navy in 2001 was 1,046 Mk-48 torpedoes.
  • In 2017 Lockheed's production was approximately 50 per year.
  • Mk48 production ended in 1996.  Production restarted in 2016 with initial deliveries in 2022, as best I can tell.
 
Disclaimer:  As always (and always ignored!), this is not intended to be a true combat simulation.  It is intended to illustrate some concepts in a more readable - and hopefully enjoyable - format.

53 comments:

  1. I might add a detail to the story: at 30 knots, the destroyers will have significant bow waves, which will show on radar. Going slower, or just telling the ships not to proceed in a neatly dressed formation, but speed up and slow down a bit independently, to avoid someone noticing the consistently regularly spaced returns, might add verisimilitude.

    However, selling this kind of weapon system to the Navy and politicians might be hard. There's a lot of "Hollywood thinking" in the US, which would think of a *single* torpedo-armed ship or submarine needing to attack several separate targets, and thus actually needing torpedoes that will share out the targets. Massed launches aren't nearly so appealing to the Hollywood mindset, but they're necessary for semi-dumb torpedoes to be effective at long range.

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    1. " destroyers will have significant bow waves, which will show on radar."

      Maybe, maybe not. The purpose of sailing against the shore was to lose any radar return in the clutter of land. Can a surface search radar distinguish a bow wave from a wave breaking on shore against a background of land clutter? I doubt it but I don't know. If someone ran an actual test and decided that a slower speed would be better, that's fine. That really wasn't the point of the story.

      By the way, every additional minute in enemy controlled or contested waters due to going slower increases the chance of detection so it's a risk either way.

      You also noted the distances involved, right? It required several hours sailing at speed to get into launch position while still dark. Slowing puts the group into daylight and the odds on being detected increase substantially. While the amount of ambient light doesn't affect radar, it certainly does affect direct visual detection by observers on land, at sea, or afloat. In an EMCON environment, which war is, visual observation takes on increased importance.

      All in all, I'm happy with the tactical choice I made for the story although, as I say, if someone wants to get a destroyer and a radar source and conduct some tests, I'm open to modifying my thoughts.

      Now, with that out of the way, do you have any thoughts on the larger issues raised in the post such as weapons, ship design, force structure, operational planning, inventories, invasion scenarios, etc.? There's a lot of good material for discussion here. Give me some thoughts.

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    2. So, a question. Would this scenario be fundamentally better if the torpedos were carried by submarines? Better being the ship being much harder to be detected? I'm assuming that we can build a submarine that could carry and launch 40+ torpedos. If that's true, at least for this scenario - what benefit is there to use a surface ship?

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    3. "Would this scenario be fundamentally better if the torpedos were carried by submarines? ... I'm assuming that we can build a submarine that could carry and launch 40+ torpedos."

      The current Virginia class and the preceding Los Angeles class carries 25 torpedoes. 40+ would be a major increase and necessitate a major redesign of submarines.

      It would require ten subs to generate the requisite weapons and trying to operate ten subs in a restricted area is not tactically wise due to the blue-on-blue issue. Each sub would have to assume that any sub detected was an enemy but they would be hesitant to act because it would likely be a friend.

      Subs require deeper water than up against the shore and, the further out to sea, the better the chance of detection, especially of ten subs clustered in one area.

      A single sub would be a good choice (no blue-on-blue issue) but a single sub can't do the level of damage required.

      So, no, subs would not be a better choice.

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    4. A sub could launch that many torpedoes if the navy would simply develop the VLT (Vertically Launched Torpedo) launcher. Most of the basic work has already been done for Ballistic and Cruise missiles. I've always wondered what kind of performance you could get out of a torpedo the size of a Trident.

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    5. "if the navy would simply develop the VLT (Vertically Launched Torpedo)"

      What would be the point or benefit? Underwater, horizontal or vertical makes no difference.

      The issue is magazine size, not launcher. Current subs carry 25 torpedoes. Expanding the sub to 40 would require lengthening the sub - undesirable unless there were a compelling reason.

      Normally, a sub on war patrol would be lucky to encounter even a few targets. Forty torpedoes seems excessive. By the time you've expended 25 torpedoes, you're probably more than due to return to base!

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  2. This attack presupposes a number of details that enable it to happen

    1) The Chinese have no perimeter patrols or defenses of any kind, including air patrols, picket ships such as corvettes or FACs, or highly capable air defense ships such as Luyang DDGs

    2) There are no defending escorts with acoustic countermeasures that are defined to defeat modern incredibly intelligent homing torpedoes that would draw these simplistic torpedoes with no difficulty.

    3) Tying into point 1, the Chinese do not possess a radar of sufficient quality to pick out a multi-thousand ton ship moving at 30-knots from background clutter. Even a Raymarine radar that you can purchase for a sports fisherman is capable of distinguishing stationary clutter from moving targets.

    4) Less of an assumption, but more a limitation. These torpedoes launched at such ranges will be useful only against a stationary target. You can’t datalink targeting corrections to a torpedo at such ranges and in the two hours it takes these torpedoes to arrive at their target, a lot can happen. Therefore they are only useful in one specific scenario

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  3. 1) The Chinese have no perimeter patrols or defenses of any kind, including air patrols, picket ships such as corvettes or FACs, or highly capable air defense ships such as Luyang DDGs

    2) There are no defending escorts with acoustic countermeasures that are defined to defeat modern incredibly intelligent homing torpedoes that would draw these simplistic torpedoes with no difficulty.

    3) Tying into point 1, the Chinese do not possess a radar of sufficient quality to pick out a multi-thousand ton ship moving at 30-knots from background clutter. Even a Raymarine radar that you can purchase for a sports fisherman is capable of distinguishing stationary clutter from moving targets.

    4) Moving at 30 knots you’re absolutely blind to any submarine that happens to be lurking about and are going to be an utterly massive acoustic target. Again tying into point 1, that there appears to be virtually no defenses for the Chinese invasion fleet

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  4. "This attack presupposes a number of details that enable it to happen"

    Of course it does!

    You'll note from the map that the destroyers are shielded from detection on the opposite side of Taiwan for all but the final few miles after they round the southern tip of the island so Chinese ship sensors would have little or no opportunity to detect them. Airborne detection is a possibility although trying to pick out a max stealth (you caught that description in the story, right?) ship (think Visby) that is merged with the shore would be a challenge and that is further rendered unlikely by the fact that the air over the invasion fleet is vigorously contested by the US so it's not as if dozens of Chinese search aircraft are leisurely flying over the area.

    The sheer number of torpedoes renders any ship countermeasures irrelevant. They may decoy one or two but any of dozens of others will get them. The number of torpedoes was one of the discussion points of the post. Perhaps you'd care to discuss that?

    "Moving at 30 knots you’re absolutely blind to any submarine"

    Everything's a risk in war. That said, that's why the destroyers were tucked up against the shore. Trying to pick out an acoustic signature against shore noises, surf, bottom flow noise, etc. is a very difficult challenge.

    "These torpedoes launched at such ranges will be useful only against a stationary target."

    No. The premise was that simplistic weapons can compensate for the absence of networking and advanced guidance through sheer numbers. Again, this was a highlighted discussion point.

    All in all, you comment is very poor quality. You simply noted the conditions of the scenario without any discussion of the various premise points.

    You also appear to have failed to note the disclaimer that the story is not intended as a detailed combat simulation but just as a more entertaining way to illustrate various concepts.

    I encourage you to comment again but with the intent of furthering the discussion and adding some helpful information or insights.

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    1. First, sorry for two comments, I didn't see my first one post.

      But, regarding detection, I did catch the "max stealth" description, but there are absolutely no long range forces? Forces in the South China Sea are completely reduced? There are no SAGs or carrier groups in the seaward side of Taiwan? There are not FACs or corvettes patrolling even ten or twenty nm distant from the invasion fleet?

      Secondly, I think you are dramatically underestimating the effectiveness of modern acoustic countermeasures, which are designed to defeat homing torpedoes which are extremely discriminatory. It won't be one or two torpedoes being pulled off by a decoy, it will be dozens. We've had eighty years to develop homing torpedoes and we spent eighty years developing countermeasures for them.

      I also continue to see how these torpedoes are suitable against a non-stationary target. When your torpedoes have a run-to-engagement of two hours, any change in the target's bearing rate or range rate upsets your targeting solution and your weapon enables in the completely wrong spot.

      You say that your point is that numbers trumps sophistication. The problem is, the sophisticated weapon can be used for multiple roles and therefore only one type is required. Your proposed simple weapon has far less capability and flexibility and therefore represents a much higher cost-per-effectiveness achieved, even if the cost-per-unit is lower.

      "Hugging the shore" is not a viable tactic anymore. Not to mention that moving at 30-knots in shoal water would make any professional mariner piss themselves, but modern AESA radars are able to pick out ground-based targets out of ground-clutter such as the APY-7 and the APY-10.

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    2. "I didn't see my first one post."

      It went to the site's spam folder. That's a rare but persistent on-going problem that affects around 2% of the comments. I have little control over the blog mechanics so there's nothing I can do about it. That's the flip side of the blog being free. I check the spam folder several times a day and transfer the legitimate comments to the publish folder as soon as I see them.

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    3. "There are no SAGs or carrier groups in the seaward side of Taiwan?"

      I assume you're referring to the eastern side and, no, there would be no Chinese naval forces there. That side of the island would be controlled by the US Navy and Air Force. The western side would be controlled by China. Taiwan would be the prize in the middle. This is utterly predictable. Neither side will be able to operate naval forces in the other side's waters.

      "I think you are dramatically underestimating the effectiveness of modern acoustic countermeasures"

      I study this stuff relentlessly and nothing I've come across suggests very effective torpedo countermeasures. Circumstantial proof is that the Navy, several years ago, authorized an urgent anti-torpedo torpedo defensive system. They considered the need so urgent (for whatever reason) that they installed a developmental system on a deploying carrier. The system, despite lofty claims of stunning success in design and development, failed utterly in service. The system was deleted after a brief period. The implication is that the Navy does NOT believe that they have any effective countermeasures. This agrees with everything I've come across. If you have information and data that demonstrates significant torpedo countermeasure success, please share it. If not, I'll stick with my extensive readings and study which says our countermeasures are not very effective.

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    4. "When your torpedoes have a run-to-engagement of two hours, any change in the target's bearing rate or range rate upsets your targeting solution"

      Wow! You didn't get the attack concept at all. NONE of the torpedoes were given a specific target. It was a wave front of torpedoes and they would go after any target they came across when they got to the general area. With hundreds of torpedoes spread across the area, there was no need for individual targeting.

      ""Hugging the shore" is not a viable tactic anymore."

      Since you missed the attack concept, I'm going to guess that you missed the maximum stealth part, too. This would be a 'better-than-Visby' stealth ship, against the shore, on the far side of an island/mountains for most of the journey. That is about as close to zero chance of detection as I can imagine.

      If you have radar detection data relative to Visby level stealth against a shore background, on the opposite side of an island, please share it. If you don't (and obviously you don't), then you're just speculating, as am I (although, in my case, it's semi-informed via study). You're welcome to your opinion as long as you present as speculation rather than fact.
      Again, if

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    5. "moving at 30-knots in shoal water would make any professional mariner piss themselves"

      Have you ever studied wartime missions? They're all risky as hell. War is one big risk! Fortune favors the bold. You make your own luck. Etc.

      You seem to want to debate the story scenario. Since it's made up, there's not really anything to debate. You can accept it and learn from it or not. If you don't care for the post, simply ignore it and move on. Trying to debate things for which you have no definitive information is pointless and tedious. I've given you far more time than is warranted.

      Have a good day.

      Delete
  5. Yet another great post advocating single purpose platforms!! I truly think separating the ships disciplines in the future is a key to a bigger fleet and a reinvigorated shipbuilding industry. The story is a neat paralell to my thoughts on torpedoes being one of the best defensive measures for Taiwan. Elsewhere, I suggested that with a probable lack of air superiority over Taiwan, and the Strait being a very poor place for subs to operate, that shore/sea based missiles wouldn't be very survivable or able to stop an invasion fleet. But, l think maybe shoreline "forts", with subsurface torpedo tubes and large magazines might offer a better defense. With limited ability to maneuver or use any countermeasures against them, it seems as if torp-spammimg enemy fleet would be rather successful. The Oscarborg fortress' success was certainly an inspiration for that idea...

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    1. "l think maybe shoreline "forts", with subsurface torpedo tubes"

      The only drawback is that such a defensive facility would be well known and a fixed target which would be unlikely to survive the first minutes of an assault. Now, if you limit the number of torpedoes to, say, half a dozen or so and built hundreds of these facilities, that might be viable and somewhat survivable through sheer numbers. But, again, they'd be well known and located. To an enemy with sufficient firepower, which China certainly has, fixed targets are not survivable. What do you think?

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    2. Coastal Defence Truck mounted ASROC.
      The rocket in this case, is to get the anti-ship torpedo from shore to open water, not near the target, so a pretty dumb
      rocket that fly's to a point and drops the torpedo.

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    3. I've often thought that there is a definite tendency for peacetime militaries to produce general purpose designs. While specialist are more common during war time.

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    4. "While specialist are more common during war time."

      What does that tell you about the wisdom of our peacetime developments?

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    5. Id lean towards hardened installations rather than mobile launchers. I don't think anything above ground, mobile or not, will have a useful life expectancy. Maybe we are in an era where defense is always overcome by the offense (??) Can you pour enough concrete to survive?? Maybe the forts need to be more ambitious, and slightly offshore, using the sea as protection(?) Thatd certainly make them more difficult and expensive but I really believe that torps, not missiles, are the counter to an invasion. It will come only after Chinese air superiority is established and a decent amount of above-ground threats are eliminated. It's just finding the largely survivable way to house the torps thats the question. It doesnt have to be forts, maybe not even manned installations. Maybe some kind of containerized CAPTOR-like system, dropped offshore, maybe with shore control, maybe fully automatic(??) is more viable. And maybe its a combination of both??
      Apologies though, didnt mean to get so off track/post!!

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    6. "Id lean towards hardened installations"

      Bear in mind that Taiwan has some 450 miles of shoreline on the western side of the island. Where along there would you place installations? Trying to defend the entire shore would really dilute the defensive effort. Can we predict the invasion location(s)? That would certainly be helpful since we could just put defensive emplacements there and save a lot of time and resources.

      Does this change your thinking?

      "Maybe some kind of containerized CAPTOR-like system, dropped offshore,"

      Rather than that, just heavily mine your own waters during peacetime. Of course, there are some practical difficulties with that but if you think you're going to be invaded, you can deal with the difficulties.

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    7. "Can we predict the invasion location(s)?"
      I havent really analyzed that in depth- but I did read somwhere (will try and recall the paper) that there were only a half dozen (?) truly suitable sites, so based on my poor second hand recollection , Id say yes. So we can focus down significantly from the whole length of coastline. Considering the effort the Chinese have put into having military-capable Ro-Ro ships (among others), clearly port seizure is part of their menu. Now of course, even assuming the accuracy of just a half dozen viable targets, the effort of basing a defense of each around torpedo installations, as well as procuring hundreds and hundreds of torpedoes, isnt a small or cheap exercise. But Im not convinced that any above ground missile-based defense has a snowballs chance in conparison.
      Now mines are a potentially simpler and cheaper option. But theres some large drawbacks. First, Im not sure its even legal vs international law. Also, the paths thru the fields would be rapidly discernible by watching military and civilian traffic. And never mind the issues of when civilians stray and get killed. Yes all those issues are small vs being invaded, but during peacetime theyre pretty major, and enough to likely eliminate it as an option. Also, I dont think there will be more than a day or so notice before war begins, if that- not enough time to lay the fields, and any platforms attempting it would likely be attacked, destroyed, or at least dissuaded, since the Chinese will own the skies, as well as the Strait itself.
      Now am I making some mistakes or poor assumptions here that lead me to believe this? I AM generally ignoring any potential assistance from other countries including the US, but I am assuming there will be little to no meaningful assistance for at least a few days, if not longer...

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    8. "Can we predict the invasion location(s)?"
      ... Id say yes."

      Correct! Just as Germany was able to successfully narrow the D-Day assault to one of two locations, we can reliably predict China's invasion locations. I don't know what they are because I lack detailed knowledge about the many factors that go into site selection but that doesn't mean that the US and Taiwan militaries don't know the likely spot(s).

      "dont think there will be more than a day or so notice before war begins"

      You are almost certainly incorrect about this. EVERY war has a run up to war with troops, supplies, etc. being moved to staging areas as threats and fake diplomacy is undertaken. I can't think of any surprise war in history.

      Think about it. For a true surprise, no-warning war, the attacker would be starting with only their normal distribution of assets, meaning that they would not have overwhelming force available. That's not how you want to start a war. China will give us plenty of warning. Whether we take advantage of that warning and run up period is another question.

      We're in the run up phase, now, by the way. China is building their forces, exercising directly against Taiwan, shaping the battlefield, etc. and we're pretty much ignoring it.

      We'll know the assault is imminent when they start moving masses of troops to ports opposite Taiwan and start collecting all their 'merchant' ships to those same ports. We'll know when their air force starts relocating to bases closer to Taiwan. We'll know when they embark on a massive maintenance surge to get all their ships and aircraft ready. And so on. The coming of war is easy to spot. What to do about it is the challenge. We did nothing (well, nothing right) to prepare for Pearl Harbor despite a several year run up and knowing almost to the day when and how Japan would attack.

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    9. "We did nothing (well, nothing right) to prepare for Pearl Harbor despite a several year run up and knowing almost to the day when and how Japan would attack."

      Indeed... moving the Pacific Fleet from San Diego to Pearl Harbor in May of 1940 put the fleet on a plater for the Japanese. But that aside there were some actions taken at the time that we could learn from and implement today. Such as the Two Ocean Naval Act of 1940 (not that we have the industrial base to mimic the actual BUILDING of a fleet of the size required). Putting a man like George Marshall in charge (at least of the Army) and the wholesale firing of senior officers making way for the Eisenhower's and Patton's. So we need a Navy equivalent in 2024 of Marshall to clean house. But for some reason we refuse to learn from our past.

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    10. "we need a Navy equivalent in 2024 of Marshall"

      He is probably doing something in commerce, having decided that the Navy was too attached to its illusions. Meanwhile, the Navy is probably sure they have people of that quality already.

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  6. "Don’t believe the torpedo described in the story could exist?"

    Actually, I do. I was aware of 650 mm torpedoes. But I recently was considering what a new 533 mm (21-inch) torpedo for the Navy's surface fleet would be like. I haven't been thinking ambitiously enough. Aw, shucks!

    But seriously, this is an interesting, thought-provoking article.

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    1. "thought-provoking article."

      And that's what this kind of writing is intended to do: provoke thought about larger issues. So many people want to argue the exact specifications of the imagined torpedo or debate the acoustic/radar signature of the imagined destroyers instead of considering and discussing the larger concepts, as suggested at the end of the post. Whether my hypothetical scenario could actually happen or whether my imagined torpedo and destroyer could actually exist and function the way I described is almost immaterial. The larger issue is the overall weapons selection, force structure, tactical and operational planning, China War Plan Orange thinking, and so on. To those people, I would say, forget that I ever wrote anything specific and just go think and comment about the larger issues. The specifics were just a way to make the concepts easier to grasp and more entertaining to read (I hope!)

      Good on you for getting it!

      Delete
  7. Excellent scenario I think these posts are great. In world war 2 destroyer squadrons frequently launched volleys of torpedoes at range, in ambush or otherwise, and normally did minimal damage. Do you think modern technology would improve or worsen the results of this tactic?

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    1. These are semi-smart torpedoes: they home on sound sources. Presumably they can be told to wait for a specified time before starting to do that. They also need to recognise other torpedoes of the same type and not home on those, or this attack would be an expensive fiasco.

      Delete
    2. "normally did minimal damage."

      The Japanese Long Lance torpedo volleys certainly did major damage, sinking or badly damaging many ships. The US torpedoes had far less success in terms of sinkings/damage.

      However, sinking/damaging is not the sole extent of a successful torpedo attack. ALL torpedo attacks, by any side, cause tremendous disruption to the defender's battle line and situational awareness. Ships lost their carefully rehearsed, mutually supporting positional relationships as the scattered independently. The scattering resulted in doubts about potential target identification and caused hesitation in opening fire which gave the attacker an added advantage. Scattering ships got in each other's way, masking their fire or, in some documented cases, wound up receiving friendly fire in the confusion.

      As evidenced repeatedly around Guadalcanal, a calm, orderly, synchronized, controlled battle line would, in an instant, turn into a confused mess of chaos and uncertainty. Read the Guadalcanal naval battle accounts and you'll instantly understand the true and full impact of a torpedo attack.

      "Do you think modern technology would improve or worsen"

      Modern wake and acoustic homing torpedoes are a very difficult weapon to counter and torpedoes will be much more effective. Torpedo countermeasures have languished.

      The challenge for attackers is to achieve the position (meaning close enough range) to launch torpedoes. The US Navy can't even envision themselves or an enemy getting into torpedo range. They believe naval combat will be fought with missiles at hundreds of miles. Of course, they also believed dogfights were a thing of the past and that was wrong (and still is!) so I put no stock in whatever the Navy believes. I've repeatedly demonstrated how slightly unconventional tactics can completely invalidate our assumptions.

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    3. "These are semi-smart torpedoes"

      They are MINIMALLY SMART. As you know, one of my overarching themes on the blog is that our weapons (and ships and planes and everything) should be JUST smart enough to accomplish their function AND NO MORE. If we can accomplish that without fancy electronics and complex software, that's ideal. If we need some degree of intelligence then it must the MINIMAL amount not the maximum that we can imagine (which is exactly the flawed approach we use to design systems today and which inexorably leads to runaway costs, poor performance, poor readiness, poor production rates, and protracted schedules).

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    4. An alternative for closer range work would be inertial guided super-cavitating torpedoes (100+ knots).

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    5. "super-cavitating torpedoes"

      Likely more expensive and harder to produce with little or no gain in combat effectiveness.

      Delete
    6. "Of course, they also believed dogfights were a thing of the past and that was wrong (and still is!)"

      If we're referring to Vietnam, that was the Air Force, not the Navy, compounded by the issue that USAF at the time subcribed to the Universal Pilot theory: the idea that every pilot is just a cog in the machine, a human control interface, and can therefore be retrained to pilot a fighter or bomber at will. We know how that turned out.

      It's interesting to note that in the same period of time, with essentially the same aircraft type and the same missiles, Navy F-4 squadrons had higher kill rates and accuracy with the Sidewinder missile compared to their Air Force counterparts.

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    7. "that was the Air Force, not the Navy"

      No, the Navy absolutely bought into the 'end of the dogfight era'. As evidence, the Navy adopted the F-4 Phantom which had no internal gun on any of its models (B, N, J, S).

      The Air Force added an internal gun on the F-4E.

      Delete
  8. A couple additional thoughts on submarines:

    (1) Vertical launch. "What would be the point or benefit? Underwater, horizontal or vertical makes no difference."

    One major difference is that vertical launch (at least as implemented on US submarines) allows much faster firing, since you don't have to be constantly reloading torpedo tubes.

    (2) Magazine depth. The Virginia Block 5 will be able to vertically launch 40 Tomahawk sized objects. Obviously somewhat fewer of your 65 cm torpedoes, but since the torpedoes haven't been designed yet, maybe we could live with 21 inch? Obviously this does not eliminate the problem of requiring multiple submarines and coordinating among them. On the other hand, if any of the Ohio SSGNs are still in service during this war, they can vertically launch 154 Tomahawk sized objects (basically the same size as the Mark 48 Torpedo). Is that enough for one ship to do this attack? If not, possibly with some creativity we could double the 154 by stacking two torpedoes in each vertical tube. The D5 missile (which is what the ships were designed to launch) is about 45 feet long, but torpedoes tend to be about half or less of that.

    (3) Although much of the Taiwan Strait is a bit shallow for submarines, there is very deep water off the Southwestern part of the island, which would be very suitable for submarines.

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    1. "vertical launch (at least as implemented on US submarines)"

      I'm unaware of any vertical torpedo launch capability on US subs. Are you just speculating or do you know of something?

      "allows much faster firing"

      I'm not sure that's true. My vague understanding is that vertical launch on subs requires a somewhat extended launch cycle. In other words, you can't simply launch simultaneously or even one every second. I don't know what the launch cycle time period is and I may be completely wrong.

      On the other hand, a surface ship, horizontal ejection sequence from two separate sets of launchers ought to be capable of rapid fire and, of course, the imaginary destroyers were given rapid reload capability as mentioned in the post.

      "Obviously somewhat fewer of your 65 cm torpedoes,"

      I'm not sure a VPM individual tube can fit a 650 mm (25.6" diam). Also, remember that everything is 'all up rounds' today so that would further increase the diameter requirement. Maybe you can find some information on this?

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    2. "I'm unaware of any vertical torpedo launch capability on US subs."

      You're correct. There isn't one NOW. I was actually referring to the comment earlier from the guy who said we ought to complete it. Remember, your "Fletcher 2" ship and 65cm torpedo don't exist either, so as long as we're fantasizing, we get to fantasize about other things too.

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    3. "My vague understanding is that vertical launch on subs requires a somewhat extended launch cycle"

      Well, I haven't found data on how rapidly the launches can be done, and it's probably classified anyway. There is this article in National Interest:

      https://nationalinterest.org/blog/the-buzz/the-navy-has-one-submarine-could-drop-154-tomahawks-missiles-23529

      which states that the SSGNs have 154 Tomahawks, "all of which can be ripple-fired from underwater in the space of six minutes"

      This document, which is a thesis from the Naval Postgraduate School, is from the early "oughts" and addresses the question of how to incorporate the SSGNs into the system of allocating missile firing to different "firing units" (ships) during a strike:

      https://apps.dtic.mil/sti/tr/pdf/ADA407619.pdf

      This states that a minimum of 20 seconds (subject to change) is required between missile launches "to allow seawater to fill the empty canister after a missile is launched, and to
      allow any debris from the missile launch to drift clear of the missile tube so that it does not
      interfere with subsequent launches and missile muzzle hatch operations."

      So, more conservative than the National Interest article.

      I will mention, though, that given your comments in other contexts that large salvos of missiles will be required in any combat against a peer competitor, if our SSGNs are incapable of producing that it would be a major limitation.

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    4. "I'm not sure a VPM individual tube can fit a 650 mm (25.6" diam)"

      Well, there may be a miscommunication here. The VPM consists of four tubes, each of which can hold 7 Tomahawks. Or probably 7 Mark 48's, which I believe are pretty much the same diameter as Tomahawks since both can be fired from normal torpedo tubes. Then there's an internal structure to subdivide it into smaller sections for the individual tomahawks. Obviously, to handle a larger torpedo that individual structure would need to be modified, just as it will need to be modified for the upcoming hypersonic missile or any other weapon. That's one reason I suggested that, if you could live with a 21 inch torpedo it might be a little simpler.

      However, modifying the internal structure of the VPM is surely less of a major change than designing and building an entire new class of ship! So there's that.

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    5. "Allows much faster firing". One last comment on that. Note that when I said this, I wasn't comparing it your your Fletcher 2's launchers. I was comparing the VLS to firing 40 torpedoes out of the torpedo tubes on the submarine. It seems sort of self-evident that the statement is true in that case, since reloading a torpedo tube on a submarine is not a super fast process.

      Delete
    6. "we get to fantasize about other things too."

      That's fair!

      Delete
    7. "minimum of 20 seconds"

      That's in line with my vague understanding. Unlike a surface ship VLS where the air clears almost instantaneously, water takes some time to settle and clear. So, perhaps 2-3 launches per minute.

      "large salvos of missiles will be required in any combat against a peer competitor, if our SSGNs are incapable of producing that it would be a major limitation."

      I see no practical problem. Via the magic of waypoints and programmable routes, a relatively drawn out launch can still easily result in simultaneous time on target.

      Delete
    8. "VPM consists of four tubes, each of which can hold 7 Tomahawks"

      You've got it. My guesstimate is that each of the four tubes might be able to hold 3x 650 mm torpedoes depending on the actual dimensions of an all up round which will be larger than 650 mm. So, for a Virginia class sub, that would be around 12 torpedoes in the VPM. Without actual dimensions, just speculation.

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    9. The Mk 48 torpedoes are 20 feet long. The Type 65 torpedoes are longer at 30 feet and weigh about 8,800 pounds. The Virginia-class are 34 feet in diameter.

      I don't see how a Type 65-like torpedo would fit in a VPM missile tube.

      Delete
  9. 650mm torpedoes would be nice to have, but would it be possible to double the fuel tank capacity and improve engine / propeller efficiency (possibly already done) of our existing 533mm torpedoes to provide the necessary range increase?

    Otto Fuel II is around 1,100btu/lb or 11,275btu/gallon, according to this online patent document:
    https://patents.google.com/patent/US6032460A/en

    If the Mk48 fuel tank's capacity is 0.45m^3 (533mmDx2mL), then it holds 554.4kg or 394kWh of fuel (Otto Fuel II is 1,232kg/m^3). An old Janes doc, maybe incorrect, estimated Mk48 ADCAP range at 40kts to be 31 miles. That equates to burning 33,608.2btu/min or 30.55lbs/min or 9,850Wh/min, about 591kW of power. With a 33% thermally efficient piston engine, that implies about 264hp, I think?

    The WWII Japanese Type 92, very similar in weight / size to the current Mk48 Mod 7, was powered by a 95hp electric motor and achieved 30 knots.

    Let's say we needed 18.33lb/min to achieve 30knots. Our tank gives us 66 minutes of run time, or 37.95 miles of range. That means our fuel tank volume needs to increase by 2.24X (a bit over 1m^3) to give us 85 miles. Our increased capacity fuel tank would be 4.6m long. We're testing composite Otto fuel tanks, so perhaps dry weight could remain similar to the original steel tank.

    The entire weapon is only 5.8m long, so that's not achievable without a reduction in electronics volume. Maybe the weapon's length could increase by 1.2m, sufficient volume for the warhead and motor, but the guidance package still needs to shrink. UK's Spearfish is 7m long, so maybe this could work. It has some horrifically toxic propellants, but nets a 40% improvement in energy density over Otto Fuel II. It still can't cover the distance required, but it's powered by a small turbine for high power output, and efficiency suffers a lot with small turbines.

    650mm would make this task trivially easy (cheap), requiring no special fuels or construction methods. Fielding proper super heavy weight torpedoes for long range ship killing looks pretty reasonable to me.

    kbd512

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  10. I really liked this post, which offers a great example of the potential value of both specialized platforms and employing low cost weapons at volume.

    For those who are skeptical, as a former naval officer I can tell you that if someone fired 100+ torpedoes into a fleet like this it's going to cause some hurt. I don't need to know anything more about the torpedoes or the countermeasures. At some point, numbers like that will simply overwhelm the system. At the bare minimum it will cause all sorts of operational havoc for some period of time, which might be a good enough tactical result for the attack to be considered a success. I think that was the point being made here.

    Now...I also agree with the commenters who challenge if these ships could get in a position to make this attack as described. Your responses seem to boil down to "didn't I say these were undetectable ships operating undetectably?" I don't think that's realistic and I agree with those who have pointed out a variety of challenges that would likely have to be addressed for this sort of operation to be successful (For the record, I think they could be, I just don't think 100% reliance on stealth and passive measures would be sufficient.)

    Since there's no way to know who is right short of going out and running a Fletcher along the beach at flank speed and painting it with a bunch of radars -- which sounds awesome, by the way -- maybe everyone could give a little on that issue! Warfighting is pretty hard.

    Having said all that: great post. Lots to think about.

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    1. "challenges that would likely have to be addressed ... I think they could be"

      Excellent! Now, take a stab at describing some ways that detection could be avoided. One of the problems I see with today's Navy (you didn't say what era you're from!) is that there is little emphasis on tactics to over come problems instead of pure dependence on technology.

      "operating undetectably"

      Bear in mind that my scenario depends not only on radar stealth to reach launch position but all the other aspects of combat. For example, the scenario is a Chinese invasion of Taiwan with the US resisting. With that in mind, Taiwan becomes a Guadalcanal of ships, missiles, and aircraft from both sides being constantly fed into the meat grinder. Both sides personnel are exhausted, alarms (both real and false) are continuous which causes alarm fatigue and people pay less attention, minor radar contacts (which is what a stealth ship would appear as) around the periphery won't be pursued as intensely (if at all) as high priority incoming attacks, there will literally be thousands of contact reports and only the very highest can be actively pursued, confusion reigns as it does in any real combat setting, and so on. Combined with the ultimate in stealth and the island of Taiwan between the ships and the invasion fleet for most of the way, the odds of detection are low. I stand by my assessment.

      "no way to know who is right short of going out and running a Fletcher along the beach at flank speed and painting it with a bunch of radars"

      This is why I keep saying we should be running realistic field exercises and tests - so we know what works and what doesn't. Can you see that destroyer tucked up against the shore or not? I've probably put more thought into this than the Navy has!

      "Lots to think about."

      And THAT'S the purpose of the post - to get people to think about force structure, ship design, weapon selection and utilization, innovative tactics, and so on.

      Maybe you'd like to offer some thoughts based on your service experience? That would be invaluable.

      Good comment!

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    2. "Lots to think about."

      Forget about my scenario and solution. If you were the US commander and tasked with opening up the southern flank of a Chinese invasion fleet, how would you go about it? If you can't do it with existing platforms and weapons, what imaginary assets would you need to accomplish the task? You saw one of my possible solutions - what's yours? This is how we developed War Plan Orange prior to WWII. We should be doing the same for China, now, while we have the time.

      What would you do?

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  11. How many torpedoes could you stuff into a purpose built shipping container?

    If you had a small cargo ship carrying containers you could potentially launch an awful lot of torpedoes very quickly.

    Or leave them somewhere that they could be launched. Potentially semi buried in shallow water somewhere and operated by a small contingent of marines?

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    1. "small cargo ship carrying containers you could potentially launch an awful lot of torpedoes very quickly."

      Do you really think an enemy is going to allow an unidentified cargo ship to get anywhere near them? In war, EVERY ship that isn't positively ID'ed as friendly will be sunk.

      "buried in shallow water somewhere"

      That's called a mine.

      "operated by a small contingent of marines"

      Where will this small contingent get their targeting data?
      How will the targeting data get transmitted to these torpedoes?
      How will they provide guidance for torpedoes?

      You need to think this stuff through!

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    2. How long are the range of these torpedoes?

      I'm an infantry soldier who does not pretend to know a great deal of sea warfare theory, concepts or practise, but if a destroyer can get close enough to launch torpedoes why wouldn't a small coaster boat with two or three containers on the deck?

      "one more convoy went unremarked by Chinese infiltrators watching from the heights"

      I've seen some pretty busy areas where such a ship would simply disappear into the background of general shipping, I understand Taiwan and surrouding areas is one of the busiest sea lanes in the world.

      A semi-submerged "wrecked container" could release torpedoes with, again, infantry soldier, don't pretend to know a great deal about naval matters, some basic compass bearing heading and their own active sensors. What's the range of torpedo active and passive sonar? Could you just fire them in the general direction of passing ships and let them guide their own way? Don't know how well that'd work, but you'd only need Mk 1 eyeball and a fire control.

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    3. "why wouldn't a small coaster boat "

      If you're infantry, think mission execution! Reread the scenario and note the distances and times. The destroyers had to travel from their starting point to the launch point in darkness. A small, 'coaster' doesn't have the speed to do that and would wind up sailing in daylight when the risk goes way up. The mission had to be executed QUICKLY and during darkness to avoid the most common sensor, the eyeball.

      "I've seen some pretty busy areas where such a ship would simply disappear into the background of general shipping"

      You have ... but it was during peacetime. In war, there will be NO civilian traffic anywhere near a war zone because both sides will be sinking anything they can't positively ID as friendly. A single civilian boat will stand out like a sore thumb and be sunk instantly.

      Consider the example of the Houthis and the Red Sea. Most civilian traffic has re-routed and that's not even a high level war zone.

      "you'd only need Mk 1 eyeball and a fire control."

      The range of the Mk 1 is around 8 miles at sea level. That's not a useful range.

      How do you program a torpedo in a box?
      How does the torpedo get out of the box?
      How do the pile of torpedoes in the box know which one(s) should launch?

      This is the kind of idea that may seem appealing at first glance but with a tiny bit of understanding becomes instantly not feasible.

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