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Wake-homing torpedoes...

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  • Wake-homing torpedoes...

    How do they function, as in, by what means/sensors are they able to home-in on a ships wake? I ran a Google search but didn't find any satisfactory descriptions or explanations.
    The black flag is raised: Ban them all... Let the Admin sort them out.

    I know I'm going to have the last word... I have powers of deletion and lock.

  • #2
    This stuff is russian know-how. Used for long-range 650mm torpedoes.
    After the big ship passes, water changes it's properties for a long time. Torpedo tests water and knows that it crossed a "wake", it turns back. Crosses it again and continues to do that until it is close to the ship. No accoustic countermeasures can help against this.

    p.s. At least one person was put in jail for publishing basic physical principles used in this system in 2001.

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    • #3
      Originally posted by lurker
      This stuff is russian know-how. Used for long-range 650mm torpedoes.
      After the big ship passes, water changes it's properties for a long time. Torpedo tests water and knows that it crossed a "wake", it turns back. Crosses it again and continues to do that until it is close to the ship. No accoustic countermeasures can help against this.

      p.s. At least one person was put in jail for publishing basic physical principles used in this system in 2001.
      Very interesting. I can even imagine how they managed to identify which direction to turn based on that track!

      Was that guy Mr. Endmong Poupe? I remember one former american NAVY had been jailed for buying info on torpedos.... but then released by Putin as a sign of good will.

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      • #4
        Originally posted by Garry
        Very interesting. I can even imagine how they managed to identify which direction to turn based on that track!

        Was that guy Mr. Endmong Poupe? I remember one former american NAVY had been jailed for buying info on torpedos.... but then released by Putin as a sign of good will.
        No. It was Sutyagin, he got 15 years. About the wake-homing look here, item 2) b)

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        • #5
          Wake Homing

          Originally posted by lurker View Post
          This stuff is russian know-how. Used for long-range 650mm torpedoes.
          After the big ship passes, water changes it's properties for a long time. Torpedo tests water and knows that it crossed a "wake", it turns back. Crosses it again and continues to do that until it is close to the ship. No accoustic countermeasures can help against this.

          p.s. At least one person was put in jail for publishing basic physical principles used in this system in 2001.
          Found this thread randomly in a google search and thought I'd fill it in a bit.

          The technology is widely understood and exported now adays. The torpedo runs shallow with a high frequency sonar facing towards the surface and it looks for the bubble trail produced by a ship. Ships naturally suck air down under their hull as they move forward, often cavitate with their screws, and on top of that US warships for a long time have employed Praire/Masker noise reducing systems that create even more bubbles in their wake (look at pics of US ships underway during exercises and you'll an nearly white trail behind them). This bubble trail is what the high freq sonar looks for, the same way an active sonar torpedo will detect a bubbling noise maker - the sonar wave reflects off the bubble curtain due to the density change between the water and the air. There isn't a way to effectively hide your wake other than stopping and waiting for it to disburse. Ship size, speed, blade design, and operation of bubbling noise suppression systems will alter the size and duration of the wake.

          The torpedo has to be set with an activation range (it will ignore all wakes until active) and also needs a setting to decide the turn angle when it finishes crossing the wake - it doesn't know if it should go left or right when it finds the wake, it only knows that there *is* a wake. If the turn angle is set incorrectly, it will proceed in the opposite direction of the ship down the wake. Evasive maneuvers also can cause this to occur by either pulling a 180 degree turn in the direction of the fish or crossing your own wake. If the torpedo successfully follows the wake in the right direction, it crossing back over the wake until it leaves it, then doubles back and crosses in the opposite direction, zig-zagging up the wake to the ship propper where it will generally magnetically and acoustically fuse underneath the tail end of the ship.

          I'm not aware of any system that can decoy a wake homer; for instance I don't believe 'nixie' is effective. However an escorting ship can act as live bait. The USN also has now deployed an anti-wake homing torpedo torpedo that presumably follows own wake backwards to make intercept; so far this has only been installed on a half dozen carriers and is not viewed as 100% effective in testing. I have heard anecdotally that US CVs employ devices for magnifying the width of their wake and that this has the effect of using up the torpedoes energy. Also while the wake sensor may be hard to fool, the trigger mechanism would use some kind of magnetic or acoustic (more likely both) firing that potentially be made to go off prematurely with a towed decoy.

          To the best of my knowledge the first torpedo that used this was the Russian Type 53 going back to the '60s. This was a 533mm/21" fish. The Type 65 was the industrial sized version using the same guidance mechanism first introduced in the Victor III class which is much longer ranged and has a bigger bang. The Russians have continued to upgrade the design over the years to the current version that uses Otto II fuel like the US mk48. The Chinese have copied them extensively and it is claimed that their Tu-6 torp is a copy of an older mk48 that also is equipped with wake homing as a guidance (presumably in addition to passive or active sonar).

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