Comment by sandworm101 | Hacker News Reader

Comment by sandworm101 | Hacker News Reader

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Take EVERYTHING in that article with a giant tub of salt. The specifics of torpedo combat are some of the most closely guarded military secrets.

Take the following: "These high-torque, permanent magnet electric motor torpedoes ramp up to speed in under a second. They go from sitting in a torpedo tube to 50 knots in a near-instant because they don’t have the mechanical lag and inertia thermal torpedoes must overcome during startup. "

So much of that is totally wrong. The torpedo has nothing to do with how it gets out of the tube. Its propulsor (not a propeller) wont work from the back of a torpedo tube. Starting it up in the tube, INSIDE the sub, sounds horribly dangerous. The torp is ejected by force from the sub and then starts its engine. Electric or thermal, it's doing 50+ whether it wants to or not. Once out of the tube, further acceleration potential is limited by depth/pressure. All torps have more than enough torque to start cavitating their propulsor in shallow water. To continue to automotive analogy, it doesn't matter whether your car is electric or turbine powered, acceleration is limited by how much power your tires can handle before spinning.

https://www.youtube.com/watch?v=PjoholiW1ho

And this is why you don't want that engine running prior to the torp leaving the tube.

https://www.youtube.com/watch?v=KoElLaLcfOc

More wrong stuff...

"It is best if the weapon detonates within a meter of the hull, but a contact detonation can have devastating effects against even the largest warships."

Torpedoes targeting ships definitely do not want to hit anywhere near the hull. They explode well beneath the target, tens of meters below. They don't try to directly damage the target. Their explosives create a large void of gas, a hole, under the ship. The ship then cracks in half as it 'falls' into the hole. Whether this technique is also used against submarines, with much stronger hulls, is likely classified.

https://www.youtube.com/watch?v=S6zQ0wBvh18

The Russian VA-111 Shkval torpedo explodes on impact, but then again, it's traveling underwater at 370km/h

Trivia: I'm pretty sure that shkval in Russian means heavy, stormy rain.

"squall"

shriek

But this would mean the ship also breaks when hit by two normal sea waves with the right spacing between them.

Yes. All large ships have a theoretical wave size that will snap them in half. The bigger the ship the larger this wave, mostly beyond possible.

True. The explanation given is wrong.

Proximity detonation breaks the ship from the force the gas bubble directs upwards.

There are going to be two effects. The first is a very large upward moment directly beneath the ship at the point of explosion, followed soon after by a downward moment when the explosion void is filled by the water and everything around it is pulled inwards to fill the vacuum.

The upward hit should actually be easier for a ship to resist because there is only air above the ship and it is “relatively” easy to lift the ship out of the water and into the air, but the downward pull means the ship is going to be pulled against the water and that will not move out of the way as easily or as quickly as the air. The second effect is what leads to the most damage.

The way I was taught this is that the strongest force and impulse (integral of a force over the time interval) is upwards after the explosion. The ship is already structurally destroyed at this point. Nothing works even if the ship does not immediately sink. When the ship falls donwards is when the keel breaks, hull breaks and water gets in. Any subsequent oscillation can cause more damage.

I know this is actually very important and interesting in the context of understanding how to build better ships/torpedoes, but I'm just imagining two seamen clinging to debris arguing on the exact mechanics by which the torpedo blew up their ship.

Clearly the solution is to have hinges in the middle of the keel.

That is a thing. Google "articulated tug barge".

Yeah, this explanation doesn't seem right. I suspect there is a strong component of direct damage to the hull involved.

It is pretty common for ships to have sections of it suspended in air in high seas.

Very tangential question.

I can think of only a handful of targets that the US might want to shoot at. (I realize there might be a ton, and this is my lack of imagination). The handful I can think of, almost all of them seem like they're in the supply chain to actually build the torpedos. I'm pretty skeptical of the depth of the US stockpile.

To put it another way, if there was a war so bad, the US reinstituted the draft, would these tools still be relevant? The US industrial base is mighty, and could certainly retool to meet whatever need arises, but that'll take years.

Really seems neat, but after you've taken your 20 or 50 or whatever shots, how do you resupply? Seems like you'd need special coatings or shelf stable chemicals or a hundred other things to make the super fancy weapon.

it sure _seems_ like (although I have no fucking clue, so I'm asking) the super fancy weapons are available for a few weeks if things get real bad.

_edit_ realized I didn't actually ask a question. Can the US actually build these things from, like, minerals? It's a big country, we have them. The industrial base doesn't seem tuned for actually doing that though.

_further edit_ I'm a very silly person. it seems like the only must have is a plausible second strike capability. It's great to be able to protect the free flow of oil, or defend the Kurds from chemical weapons. Hell, one of the most American things I can think of is protecting yankee clippers for safe trade. It's part of the Marine's Hymn. but clearing pirates from the shores of Tripoli isn't absolutely vital. I'd sort of thought that subs jobs in the modern world was making sure that if the US can't play, no one else can either, with moderately sized nuclear weapons. Again, I'm a very silly person. The question with the further edit is, do subs have an essential job beyond second strike cabability?

> if there was a war so bad, the US reinstituted the draft

US has something better than the draft: poverty. As long as there's a large enough pool of young people without options, there's no problem. A draft generally can only be minimally discriminatory for PR reasons, so poverty as enlistment incentive works much better.

Though, talking about US military running out of manpower is a far, far fetch, isn't? It surpasses or is extremely competitive with any other military by any measure [0][1].

According to Blind Man's Bluff, which covers submarine warfare during the cold war from the US perspective, right up to the nineties, atomic subs had 3 main roles: espionage and intelligence gathering, preserving second strike ability, shadowing enemy subs to have a chance of thwarting their strikes in case of crisis. What submarine warfare was during the cold war, right up to the end, was largely defined by the technical superiority of US subs, especially their ability to remain undetected. By the collapse of USSR, Soviet subs were about to catch up in terms of essential technology. I would be intrigued to learn what sub warfare is like now.

[0] https://en.wikipedia.org/wiki/List_of_countries_by_number_of...

[1] https://en.wikipedia.org/wiki/List_of_countries_by_military_...

Currently most military recruits come from the middle classes. Youths in poverty typically fail to meet enlistment standards due to health problems, low standardized test scores, criminal record, drug use, etc. Of course there are many exceptions but that's the general rule.

https://surface.syr.edu/cgi/viewcontent.cgi?article=1002&con...

Excerpt from DISCUSSION AND CONCLUSION:

> An important predictor to military service in the general population is family income. Those with lower family income are more likely to join the military than those with higher family income. Thus the military may indeed be a career option for those for whom there are few better opportunities.

People aren't going to sign up to get killed for that kind of money. That's why they had to be drafted in the Vietnam era.

And that's also why minimum-wage restaurant workers are going on strike in the coronavirus era.

A draft is good if the rich kids are in it too, that usually makes policy makers more sober.

Now that we have a volunteer army, there are differences between how the wars of today are fought compared to the Viet Nam war. The Viet Nam war had literally an order of magnitude more deaths than our current wars. Having a volunteer force means the soldiers have to treated better and paid more than a draftee. These wars have been a waste of lives and money but things would have been much worse if there were millions of draftees serving in the middle east and Afghanistan. Having a volunteer force in the 1960s would have meant that if the Viet Nam war would have been fought, there would have been with a lot more concern for the loss of life of the solders - it likely wouldn't have been fought anything like it was fought.

The USA should use this opportunity to step back and re-think whether registering for the draft is needed in this age. The whole draft registration program is simply a waste of millions of dollars a year.

I don't (off the top of my head) remember my sources for claims about poverty being a mechanism for manning the US military, so I won't push the point. I'll leave it at saying that I wish you were right.

You're definitely right that it's a recruiting pressure - that and the free college and the path to naturalisation. But that only holds as long as the casualties are relatively low. And the ~4k dead and ~30k wounded of Iraq was relatively low compared to the ~58k dead of Vietnam. It's not clear what kind of non-nuclear war would bring that level of dead again, but I reckon restarting the Korean war would do it.

The US industrial base was mighty, but these days it's a very pale shadow of what it was. Rampant cost cutting, outsourcing, and lack of protecting domestic production has absolutely devastated US manufacturing. There's still lots of design work that goes on, but almost all the actual manufacturing takes place elsewhere. What little is actually "made" in the US is almost entirely assembled from raw components that are themselves manufactured outside the US.

> Rampant cost cutting, outsourcing, and lack of protecting domestic production has absolutely devastated US manufacturing.

This is utterly false thing that you learn if only read news articles. The value and quantity of manufacturing is now the highest it has ever been in the US.

What has declined is the number of workers and the share of GDP. This applies to almost all OECD countries. As economies change from industrial to post-industrial, the share of manufacturing declines naturally because manufacturing productivity increases.

Agriculture is something like 3% of the GDP, yet developed countries produce more agricultural products than they did when 90% of the economy was agriculture. The same thing is happening to manufacturing.

> This is utterly false thing that you learn if only read news articles. The value and quantity of manufacturing is now the highest it has ever been in the US.

I've seen it first hand. I've talked with people that have been impacted by it. I've also seen the corporate slight of hand that tries to disguise it. Components manufactured in China, shipped to Mexico for assembly, then shipped to the US to have some decorative panels and stickers slapped on so they can put a "made in USA" sticker on the side.

Go grab virtually anything from around your house (excluding food) and it's more likely than not that that thing was manufactured in whole or in part outside the US. That didn't used to be the case. Coming out of WW2 it was rare for people to own non-domestically produced goods.

This isn't a case of US manufacturing just being so ridiculously efficient that you just don't need many companies making things. That might hold water if most goods were still manufactured in the US, but they aren't. Cars are about the only manufactured consumer good still made in the US, and even they are quite often assembled in Mexico. Pretty much any electronic device is made in China.

Here's a case study, Ikea which is a very popular furniture manufacturer (among other things) mostly assembles their products in Mexico and China. They do have some US manufacturing, but that's largely because they acquired rights to some large swaths of woodland and it makes sense to process and assemble that on site.

To be clear, you mentioned agriculture, and yes, the US does have a thriving agriculture sector, but agriculture isn't manufacturing.

The US screwed up badly when it let basic manufacturing get outsourced. When the factories making screws and transistors are all based in other countries, eventually all the other factories are going to follow them.

> I've seen it first hand.

You can't quantify manufacturing by looking around. What you see is cheap consumer products with low value added.

If you follow value chains for products manufactured in China, you quickly notice China imports high value added manufacturing products from other countries (including the US) then assembles them with cheap workforce and adds cheap components.

> Go grab virtually anything from around your house

Manufacturing can be for goods that you don't find in your house?

If you look at the German mittelstand there's a lot of businesses that make stuff for some unknown-to-the-public industrial niche.

I'm guessing the US also has a bunch of those.

>Manufacturing can be for goods that you don't find in your house?

>If you look at the German mittelstand there's a lot of businesses that make stuff for some unknown-to-the-public industrial niche.

>I'm guessing the US also has a bunch of those.

And that is exactly why he said "from your house". Home goods lend themselves very, very well to outsourcing because low initial cost is such a key design criteria and they tend to have a density and packaging requirements that make them convenient to ship. If you browse through the McMaster or Grainger catalogs you'll find that a huge number of things (maybe not a majority but likely the largest minority) are made in the US and the rest are made all over the world.

You’re talking about cheap consumer products that will always be made cheaply.

No one is going to make a consumer product like they used to. Take power tools and kitchen appliances for example. They don’t have to be make entirely of metal when plastic will do just fine for home use.

Like Germany we want to keep high quality manufacturing at home.

According to wikipedia the US stockpile of Mark 48s is over 1000, and the current manufacturer is building about 50 a year, which certainly seems like enough for a little bit. Most military manufacturing happens in country or in an allied country, and there are people in the military devoted to making sure the supply chain for this stuff is healthy, and making sure there is room for surge if needed. As for overseas needs, it's hard to imagine a scenario where the US Navy is unable to defend American convoys in the Atlantic (linking them to manufacturing and raw materials in South America, Europe and Africa) at least not in the first year of the conflict.

Of course in a total war scenario things start to change. When it's truly nation against nation in a global conflict every part of society needs to be re-tooled into a giant war machine. In WW2 the US told General Motors how many cars they were allowed to make a week, because they needed steel for tanks. I imagine any facility capable of making electronics in the US and Europe today would be re-tooled to make the chips for Mark 48s, AIM-120s, SM-2s, etc.

EDIT: Oh, and in a total war scenario, submarines are essential weapons. Remember, a total war isn't just army against army, it's also economy against economy. If you can deny your opponent access to the resources it needs you can win the conflict, and that means you need submarines to sink enemy supply convoys. This would certainly come up in a hypothetical Sino-American conflict. The overwhelming majority of Chinese imports and exports come through ports. The port of Shanghai alone gets more tonnage of supplies in and out in a month than all land routes in and out of China COMBINED get in a year.

> To put it another way, if there was a war so bad, the US reinstituted the draft, would these tools still be relevant?

The drafted people would all go to factories and boatyards to build thousands of new submarines. Each submarine would likely have no people on board, and be fully remote control.

The age old problem of "you can't hide while sending and receiving data, so you can't make a drone sub" has been solved by using below-noise-floor gold codes, so without the coding key, nobody can even tell a transmission is going on.

I'm a cryptographer, so I'm inherently curious about secret communication. It just so happens that I'm also very curious about radios, satellite communications, etc.

Do you have a link that provides more information on these "below-noise-floor gold codes"? I tried googling, but I haven't found much technical information that I trust is entirely truthful or relevant.

The principle is that if your ally has a receive antenna with a gain of X, and you use a modulation scheme with a coding gain of Y, and you transmit strong enough that your signal can be received by your ally with a snr margin of Z, then as long as your enemy doesn't have a receive antenna with gain > X+Y-Z, they can't detect your signal from the noise.

Since Y can be increased arbitaraly (at the cost of channel data capacity), it's always possible to transmit some information to your ally without your enemy seeing a transmission, it might just be a few bits per second, but theres a lot you can do with a few bits per second in warfare.

One needs to make sure that the above holds true for all possible frequency windows and time windows, so no carrier waves or high power sync pulses!

I believe the implementation is much harder than the theory - just one crystal oscillator or PLL anywhere in your radio hardware will leak some of that frequency into the output, and since the bandwidth of a crystal oscillator is super low (obviously an ideal oscillator has zero bandwidth), even a tiny leak is detectable by an enemy.

http://www.wirelesscommunication.nl/reference/chaptr05/cdma/... is relevant. How the noise floor comes into it I'm less sure, and am not about to wade through information theory textbooks on my lunchbreak.

http://pages.hmc.edu/harris/class/e11/lect7.pdf

No doubt that's what the end of the war would look like. But war is, generally speaking, a kind of work on the field. That kind of work isn't currently done by robots.

I have read the comms channels underwater are low to very low bit rate. If true, a remote controlled sub seems unrealistic.

Also a remote control sub would be continually sending data back which surely is tantamount to continually yelling "I'm here! I'm here!", so I don't really buy the RC sub theory yet. (edit: I don't buy your suggestion that it's possible to hide that. You just need to emit too much power and you can't hide that).

Correct, you can’t remote control a submerged submarine, you get maybe a few characters per minute rate of transmission. There are a few ELF stations throughout the world, the US, Russia and India all having some.

Some more info: https://en.wikipedia.org/wiki/Extremely_low_frequency which has my favorite quote. “ ... few nations have built naval ELF transmitters to communicate with their submarines while submerged. China has recently constructed the world's largest ELF facility roughly the size of New York City in order to communicate with its submarine forces without having them to surface. ...”

The antenna needed for these transmissions requires a lot of land.

Point a laser straight up at your satellite.

That's not true. I was working on a system to do (not on subs, but the techniques are applicable) that a few years ago. With a big enough array, anything is possible, see the entire field of radio-astronomy. This includes sparse arrays, as long as you have good enough time sync to do coherent integration.

Apparently, there are things called "swim out" torpedoes?

https://www.reddit.com/r/submarines/comments/at5nt4/silent_l...

https://www.youtube.com/watch?v=YbeQmfXE0ws - discussed in this video (from in the parent article)

Those are sometimes called "stealth" torps. They run quiet, and slow, so they don't want the noisy launch procedure. But they also don't do 50 knots. On the other end of the scale there are the rocket torpedoes, really missiles that fly underwater at speeds over 200 knots. You might hear them coming but won't be able to do much about them.

https://en.wikipedia.org/wiki/VA-111_Shkval

And there are even anti-aircraft torpedoes in development. They are a total gamechanger.

https://en.wikipedia.org/wiki/IDAS_(missile)

Actually, latter versions of the Mark 48 will do this, running at variable speed. Slow launch, creep towards the target, and dogleg even, then run up to 50+ knots once it's close enough to be heard. With wire guidance, the sub could essentially drive the torpedo to where they wanted it before violent speed and maneuvering would likely cut the wires.

This was depicted somewhat famously in the book Red Storm Rising. By all accounts it was accurate.

Shkval is a really special case and not the supertorpedo some made it out to be. It's a countermeasure really, and it's range is far too short to use against other submarines. It's a last resort weapon, when someone's already found you.

IDAS seems really fascinating to me though, like the "Stinger SAM mast" concepts I'd sometimes hear about. IDAS seems more practical and safe to me though. Coming up to periscope depth to take a potshot at a helo sounds like a risky maneuver to me. IDAS would give better options.

Manpad-type missiles like the British Blowpipe have been mounted on submarine masks.

A major threat to a submarine is all the helicopters and patrol aircraft with their dipping sonars etc. There are some really great pics taken from periscopes of opposition helicopters during the cold war. Nothing you'd want to see in a hot war neither.

It seems good to throw a little missile at the helicopter you've just spotted approaching, to give them something to evade and worry about as you make your escape?

A helo would have to be much more careful if it thought it might be shot at by a missile, so some deterrence effect. OTOH if you shot at it and missed it would active dip right on top of you and then launch some LWTs, and you'd be blasted.

If they could leave an autonomous missile pod floating just below the surface, with a submarine-like ESM mast, that would be more interesting. You couldn't get in dip range to verify subsurface contacts without being in MANPAD (BOTPAD?) range. Really the same idea as autonomous mines, which have a magnificent power of area denial.

The current tactical solution to people taking potshots at helicopters is flying in pairs. Whoever gets shot at evades. Whoever doesn't get shot at shoots at wherever the shot came from. The Navy doesn't use this tactic much because the ocean is relatively free of people hiding in apartment buildings and bushes with RPGs but they could quickly adopt it if needed at the expense of effectively halving the size of their helicopter fleet.

I think if I just dodged a short range missile launched from the mast of a submarine, I’d drop a torpedo immediately to force the sub to dive.

There are now wire-guided AA-missiles that are launched from torpedo tubes while the sub is underwater.

Come on, everyone who has played Dangerous Waters enough knows that the best defence against maritime patrol aircraft is for the captain to boldly surface the boat and take the pesky plane down with a shoulder-launched missile ;)

You are over-analyzing. There is nothing in the sentence you quote that says if the torpedo was launched or swam out etc. Nothing in the sentence you quote even qualified how long "near instant" was. Etc.

You are also saying you know more about this subject than the sub vet who wrote the article...?

Author is known as Jive Turkey on YouTube, and he knows his stuff.

https://www.youtube.com/channel/UC9bMgCQyFNaMPsK9GtzM5dQ

"Aaron Amick is a retired U.S. Navy submarine sonarman. He served in both Atlantic and Pacific Oceans on 688 Los Angles Class Fast Attack and Ohio class ballistic missile submarines. He has published two audiobooks on Cold War-era submarines, Akula SSN Project 971 Sub Brief and USS Nautilus SSN-571 Sub Brief."

I dunno, the author's bio suggests that he knows that he's talking about.

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