6 ms·

Soviet Underwater Firearms

79 points by vinnyglennon 11y ago

evan_ 11y ago
These are cool but I wonder if they actually see a lot of use in the wild. SCUBA diver fighting shows up in James Bond a lot but I have to imagine in real life it's more efficient to just cut an enemy diver's air hoses or wait for them to surface and shoot them while they're taking their equipment off.
- mattmanser 11y ago
  How are you going to cut their airhose when they're shooting you with an underwater assault rifle? And if you can get close enough to accurately cut the airhose, why not just stab them in the heart?
  - maaku 11y ago
    > And if you can get close enough to accurately cut the airhose, why not just stab them in the heart? Because the hose is easier, but your first point applies.
    - Symmetry 11y ago
      It's not going to be easy getting a knife through a rib cage and it must be hard to get leverage underwater.
- privong 11y ago
  > These are cool but I wonder if they actually see a lot of use in the wild. I wonder if a FOIA request to the Department of Defense requesting "information about any underwater combat engagements between frogmen and/or divers" would result in anything useful?
  - EthanHeilman 11y ago
    You might want to look into the story of Lionel Crabb, an SAS frogman suspected of being killed while performing espionage against a soviet warship. https://en.wikipedia.org/wiki/Lionel_Crabb https://en.wikipedia.org/wiki/Lionel_Crabb
    - chrisseaton 11y ago
      Where did you get the SAS part from?
      - dazc 11y ago
        Special Force: The Untold Story of 22nd Special Air Service Regiment (SAS) https://books.google.co.uk/books?id=CJ73AgAAQBAJ&pg=PA289&lpg=PA289&dq=Lionel+Crabb+sas&source=bl&ots=CIRoH0rLJ9&sig=r0zEuYM3QzYq4TMeDCBz-A-UMaQ&hl=en&sa=X&ved=0ahUKEwiD2pCEg_jKAhXHbBoKHZSwB-8Q6AEIQTAE#v=onepage&q=Lionel%20Crabb%20sas&f=false https://books.google.co.uk/books?id=CJ73AgAAQBAJ&pg=PA289&lp...
        chrisseaton 11y ago
        That doesn't say that he was in the SAS. It just has his name and SAS in the same paragraph. It says that in the past MI6 needed a person with military skills do something, as was the case with Crabb, so they decided to start cross-training SAS people to do that in the future. Neither the Wikipedia article nor this endnote says that Crabb was SAS.
        dazc 11y ago
        I was just hazarding a guess at the question: "Where did you get the SAS part from?"
    - arethuza 11y ago
      Probably more relevant to look at the UK SBS rather than the SAS.
    - 11y ago
- gaius 11y ago
  Ever tried cutting a hose? They're tough, have to be.
  - kika 11y ago
    Yep. There are knives good at this. I have this one: http://www.amazon.com/gp/product/B000FLTP0A http://www.amazon.com/gp/product/B000FLTP0A
    - gaius 11y ago
      Nice. My titanium Halcyon struggles with it, but I guess that wasn't a use case they had in mind!
- ryanlol 11y ago
  That's significantly harder than shooting them, and they aren't going to not use guns just because you aren't.
Kenan 11y ago
Ah, I recognize these from Depth (http://www.depthgame.com/guide/?command=diver http://www.depthgame.com/guide/?command=diver). Didn't know they were real-life firearms.
- ethbro 11y ago
  That day when you find XCom: Terror from the Deep items were actually built by the Soviets? Apparently that's a Monday. http://strategywiki.org/wiki/X-COM:_Terror_from_the_Deep/Equipment http://strategywiki.org/wiki/X-COM:_Terror_from_the_Deep/Equ...
willvarfar 11y ago
Underwater guns are still being developed and marketed. Here's a description of a modern supercavitating Norwegian one: http://www.hisutton.com/Special%20Forces%20diver%20technoloy%20-%20DSG%20Supercavitating%20Ammunition.html http://www.hisutton.com/Special%20Forces%20diver%20technoloy... (The book that website promotes is a good buy if you are into this kind of thing.)
- steve19 11y ago
  No, that is a underwater round, not an underwater gun. Most guns can be used underwater, but range is limited. The bullet in that round extends range from normal rifles. It has the added advantage of being able to be used in air as well (for "over the beach" assaults). But you are right, they are still developing them. Russia unveiled a new one a couple of years ago (I don't have a link on hand)
  - darklajid 11y ago
    The article has pictures and details of a Russian weapon that was new in 2013..
deleted 11y ago
[deleted]
FLTexcalibur 11y ago
Re: the last gun in the article: > The rifle’s effective firing range underwater is about 25 meters at a depth of 30 meters and 18 meters at a depth of 20 meters, according to Russia Today. Earlier in the article they associate an increase in depth with a lessened range, but with this one it's the reverse? Is that a typo or a nuance of the technology?
- rosser 11y ago
  I'm only guessing, but it's probably a nuance of the technology. The earlier weapons used cavitation created by the dart's blunt tip to stabilize it and give it range below the surface. The last gun uses a gas bubble to create a supercavitation [1] effect, which based on my quick skimming of the linked Wiki article, seems to be more effective at greater depth. Anyone with a more thorough (read: any) understanding of fluid dynamics is encouraged to correct or expand this. [1] https://en.wikipedia.org/wiki/Supercavitation https://en.wikipedia.org/wiki/Supercavitation
  - semi-extrinsic 11y ago
    Ok, let's try: boiling and (super)cavitation are two sides of the same thing. A liquid will turn to vapor (boil) when a physical property of the liquid called "vapor pressure" becomes greater than the actual pressure. When you normally boil water, you increase the temperature of the water, which increases the water property "vapor pressure" until it becomes equal to atmospheric pressure at 100 C. Or if you are at Mt. Everest, where the pressure is lower, water boils at 71 C. When cavitation occurs, the opposite is done: you lower pressure until you reach the vapor pressure of the liquid at the current temperature. In supercavitation, you create a shockwave in front of the bullet/torpedo/propeller which raises and then lowers pressure such that the water boils/cavitates. Why is this good? Because it lets you put most of the velocity difference between the bullet and the water inside a gas layer. This gas layer has much less resistance to velocity differences than water. Running in water is much harder than running in air, right? So far so good. So what happens when a supercavitating bullet is fired at greater depth? The pressure is higher, so it's harder to create cavitation, because you have to lower the pressure more to get to the vapor pressure. Why is that good? Doesn't it reduce the nice gas layer? Yes, it does. My guess is that it also reduces the length of the cavitation bubble behind the bullet, and that reduction in drag is bigger than the increase in drag from a thinner gas layer. In the older guns, the trailing gas bubble is much shorter because of the projectile shape, and the reduced bubble length at greater depth causes part of the projectile to be outside the bubble, increasing resistance. You could probably put some decent numerical estimates up by spending an afternoon with White's Viscous Fluid Flow and a steam table.
jemfinch 11y ago
Defense in depth.
dh997 11y ago
Nato has also had the H&K P11 since the 70's. https://en.wikipedia.org/wiki/Heckler_%26_Koch_P11 https://en.wikipedia.org/wiki/Heckler_%26_Koch_P11
- darklajid 11y ago
  That weapon is mentioned and linked in the article already though, no?
dsfyu404ed 11y ago
"fall apart and sink" is a pretty mild way of describing what happens when a rifle round hits water....

79 points by vinnyglennon 11y ago

evan_ 11y ago

These are cool but I wonder if they actually see a lot of use in the wild. SCUBA diver fighting shows up in James Bond a lot but I have to imagine in real life it's more efficient to just cut an enemy diver's air hoses or wait for them to surface and shoot them while they're taking their equipment off.

mattmanser 11y ago
How are you going to cut their airhose when they're shooting you with an underwater assault rifle? And if you can get close enough to accurately cut the airhose, why not just stab them in the heart?
- maaku 11y ago
  > And if you can get close enough to accurately cut the airhose, why not just stab them in the heart? Because the hose is easier, but your first point applies.
  - Symmetry 11y ago
    It's not going to be easy getting a knife through a rib cage and it must be hard to get leverage underwater.
privong 11y ago
> These are cool but I wonder if they actually see a lot of use in the wild. I wonder if a FOIA request to the Department of Defense requesting "information about any underwater combat engagements between frogmen and/or divers" would result in anything useful?
- EthanHeilman 11y ago
  You might want to look into the story of Lionel Crabb, an SAS frogman suspected of being killed while performing espionage against a soviet warship. https://en.wikipedia.org/wiki/Lionel_Crabb https://en.wikipedia.org/wiki/Lionel_Crabb
  - chrisseaton 11y ago
    Where did you get the SAS part from?
    - dazc 11y ago
      Special Force: The Untold Story of 22nd Special Air Service Regiment (SAS) https://books.google.co.uk/books?id=CJ73AgAAQBAJ&pg=PA289&lpg=PA289&dq=Lionel+Crabb+sas&source=bl&ots=CIRoH0rLJ9&sig=r0zEuYM3QzYq4TMeDCBz-A-UMaQ&hl=en&sa=X&ved=0ahUKEwiD2pCEg_jKAhXHbBoKHZSwB-8Q6AEIQTAE#v=onepage&q=Lionel%20Crabb%20sas&f=false https://books.google.co.uk/books?id=CJ73AgAAQBAJ&pg=PA289&lp...
      - chrisseaton 11y ago
        That doesn't say that he was in the SAS. It just has his name and SAS in the same paragraph. It says that in the past MI6 needed a person with military skills do something, as was the case with Crabb, so they decided to start cross-training SAS people to do that in the future. Neither the Wikipedia article nor this endnote says that Crabb was SAS.
        dazc 11y ago
        I was just hazarding a guess at the question: "Where did you get the SAS part from?"
  - arethuza 11y ago
    Probably more relevant to look at the UK SBS rather than the SAS.
  - 11y ago
gaius 11y ago
Ever tried cutting a hose? They're tough, have to be.
- kika 11y ago
  Yep. There are knives good at this. I have this one: http://www.amazon.com/gp/product/B000FLTP0A http://www.amazon.com/gp/product/B000FLTP0A
  - gaius 11y ago
    Nice. My titanium Halcyon struggles with it, but I guess that wasn't a use case they had in mind!
ryanlol 11y ago
That's significantly harder than shooting them, and they aren't going to not use guns just because you aren't.

Kenan 11y ago

Ah, I recognize these from Depth (http://www.depthgame.com/guide/?command=diver http://www.depthgame.com/guide/?command=diver). Didn't know they were real-life firearms.

ethbro 11y ago
That day when you find XCom: Terror from the Deep items were actually built by the Soviets? Apparently that's a Monday. http://strategywiki.org/wiki/X-COM:_Terror_from_the_Deep/Equipment http://strategywiki.org/wiki/X-COM:_Terror_from_the_Deep/Equ...

willvarfar 11y ago

Underwater guns are still being developed and marketed. Here's a description of a modern supercavitating Norwegian one: http://www.hisutton.com/Special%20Forces%20diver%20technoloy%20-%20DSG%20Supercavitating%20Ammunition.html http://www.hisutton.com/Special%20Forces%20diver%20technoloy... (The book that website promotes is a good buy if you are into this kind of thing.)

steve19 11y ago
No, that is a underwater round, not an underwater gun. Most guns can be used underwater, but range is limited. The bullet in that round extends range from normal rifles. It has the added advantage of being able to be used in air as well (for "over the beach" assaults). But you are right, they are still developing them. Russia unveiled a new one a couple of years ago (I don't have a link on hand)
- darklajid 11y ago
  The article has pictures and details of a Russian weapon that was new in 2013..

deleted 11y ago

[deleted]

FLTexcalibur 11y ago

Re: the last gun in the article: > The rifle’s effective firing range underwater is about 25 meters at a depth of 30 meters and 18 meters at a depth of 20 meters, according to Russia Today. Earlier in the article they associate an increase in depth with a lessened range, but with this one it's the reverse? Is that a typo or a nuance of the technology?

rosser 11y ago
I'm only guessing, but it's probably a nuance of the technology. The earlier weapons used cavitation created by the dart's blunt tip to stabilize it and give it range below the surface. The last gun uses a gas bubble to create a supercavitation [1] effect, which based on my quick skimming of the linked Wiki article, seems to be more effective at greater depth. Anyone with a more thorough (read: any) understanding of fluid dynamics is encouraged to correct or expand this. [1] https://en.wikipedia.org/wiki/Supercavitation https://en.wikipedia.org/wiki/Supercavitation
- semi-extrinsic 11y ago
  Ok, let's try: boiling and (super)cavitation are two sides of the same thing. A liquid will turn to vapor (boil) when a physical property of the liquid called "vapor pressure" becomes greater than the actual pressure. When you normally boil water, you increase the temperature of the water, which increases the water property "vapor pressure" until it becomes equal to atmospheric pressure at 100 C. Or if you are at Mt. Everest, where the pressure is lower, water boils at 71 C. When cavitation occurs, the opposite is done: you lower pressure until you reach the vapor pressure of the liquid at the current temperature. In supercavitation, you create a shockwave in front of the bullet/torpedo/propeller which raises and then lowers pressure such that the water boils/cavitates. Why is this good? Because it lets you put most of the velocity difference between the bullet and the water inside a gas layer. This gas layer has much less resistance to velocity differences than water. Running in water is much harder than running in air, right? So far so good. So what happens when a supercavitating bullet is fired at greater depth? The pressure is higher, so it's harder to create cavitation, because you have to lower the pressure more to get to the vapor pressure. Why is that good? Doesn't it reduce the nice gas layer? Yes, it does. My guess is that it also reduces the length of the cavitation bubble behind the bullet, and that reduction in drag is bigger than the increase in drag from a thinner gas layer. In the older guns, the trailing gas bubble is much shorter because of the projectile shape, and the reduced bubble length at greater depth causes part of the projectile to be outside the bubble, increasing resistance. You could probably put some decent numerical estimates up by spending an afternoon with White's Viscous Fluid Flow and a steam table.

jemfinch 11y ago

Defense in depth.

dh997 11y ago

Nato has also had the H&K P11 since the 70's. https://en.wikipedia.org/wiki/Heckler_%26_Koch_P11 https://en.wikipedia.org/wiki/Heckler_%26_Koch_P11

darklajid 11y ago
That weapon is mentioned and linked in the article already though, no?

dsfyu404ed 11y ago

"fall apart and sink" is a pretty mild way of describing what happens when a rifle round hits water....