why Soviet frogman rifle shorter range in deeper water?

Discussion in 'All Things Boats & Boating' started by Squidly-Diddly, Feb 16, 2018.

  1. SamSam
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    SamSam Senior Member

    Select fire up to 10 rounds a second and a range of 100 ft. That sounds like it would work much better than a spear gun for fishing....I wonder if these things would be legal for everyday use? It's hard to see why not, considering what it's ok to do here already.
     
  2. SamSam
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    SamSam Senior Member

  3. daiquiri
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    daiquiri Engineering and Design

    Don't know, perhaps Russians are not interested in selling it to civilians?
     
  4. Squidly-Diddly
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    Squidly-Diddly Senior Member

    If viscosity basically DOUBLES only 10 meters down, how are fairly high speed navy subs and torpedoes effected at 100, 200 or 300 meters?

    How big a component of overall drag is viscosity?

    I never heard any scuba divers mention it was harder to swim 10 or 20 meters down.

    As far as I can tell, things like clouds of silt stirred up look just the same at 30 meters down as they do in 12" of water.

    Yeah, I know sub to sub combat is mostly about being quiet instead of being fast, but that brings up yet another issue...how does greater viscosity effect the 'noise' created by screw-prop and rest of sub moving through water?
     
  5. philSweet
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    philSweet Senior Member

    Check your math. 1.1 MPa is 100 meters. Doubling would need 100,000 meters depth.
     
  6. Angélique
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    Angélique aka Angel (only by name)

    Off topic here, but since the OP brought it up a bit, some nowaday fast stealth from subs for Naval surface vessels . . .

    Wanting stealth from submarines is often one of the reasons to equip new Naval surface craft with water jets instead of props, which also makes them faster, and more fuel efficient at high speeds . . .

    See for this: Naval TechnologyFeb. 4, 2009 - Analysis - Waterjets Propel Sweden’s Visby to Success
    See stealth from subs also: Naval TechnologyFeb. 13, 2014 - Analysis - A class in stealth – the world’s best navy corvettes

    The Swedish fibers & plastics Visby-class corvettes, with their water jets, also apparently have proved themselves to be very capable in ice when handled right...

    See for this a recent Naval ice chat in the thread: Planning a workboat buildpost #16 - 17 - 18

    For a trapped in ice high-strength steel hull, also with water jet propulsion, see the thread: Real Ocean Newspost #46
     
    Last edited: Feb 23, 2018

  7. gonzo
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    gonzo Senior Member

    Where do you get the data that viscosity doubles 10 meters down?
     
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