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Probably a stupid question

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  • Probably a stupid question

    I have and old Lowrance X15 paper graph that I'm comfortable using. I realize this is not a side scan sonar and probably no where near the same creature.
    That said can a person aim the transducer for one of these units side ways? and get any kind of reasonable image?
    I live along the banks of the Mississippi river, the water here is not deep 0 to 40 ft tops. There is a sunken boat I would like to search for come warmer weather. With shallow water and a 60 degree cone on the Lowrance it makes for a very narrow grid pattern. I know in most places I would have to literally run over the sunken boat to see any noticable image. The survivors from the boat leave one looking in a pretty large area. So I need to widden the search grid.
    If I'm able to hang my transducer down in the water and keep it pointed to the side. Is it unreal to think I might be able to cover a larger area with my old unit?
    This is just a hobby for me and kind of a one time search of this type. So investing in a true side scan wouldn't really be practical.

    Any input would be greatly appreciated.

    Mac
    "Never Forget Which Way Is Up!"

  • #2
    Not a stupid question.

    That's exactly what the first sidescan sonars were.

    You've got what you need; why not give it a try? Mount the xducer on some sort of a towfish to get away from the rocking motion which moves the beam around too much. Even the 25 feet or so of cable on most transducers is enough to de-couple the fish from most boat motion. My first homebuilt was a transducer stuck on a 2 x 4 with a plywood vertical fin to make it go staight and a lead weight to hold it more or less level. Tow it past known submerged objects and see what kind of image you get. Grayline off. Paper speed fast. Boat speed slow.

    Investment: nearly free but for your time. Results: A meaningful learning experience; time spent on the water; maybe a wreck found.

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    • #3
      Thanks Dan
      What is the best way to tow a fish? Make it heavy and run it off a davit? or just tow behind the boat off a corner tie out?
      As for building a tow fish I have a pretty decent supply of tools and I'm fairly handy at fabricating things. Is it best to have a tow fish be real heavy? or just enough to sink it?
      I'm going to be running this off a 14ft fishing boat so I'm pretty limited in some ways.

      Mac
      "Never Forget Which Way Is Up!"

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      • #4
        Not a stupid question.

        Mac,

        The best way to tow a towfish is from a dedicated research vessel with a professional crew and air-conditioned control van. Lacking that, you want to find a happy medium - heavy & slow enough to get down a ways to minimize surface clutter while still having a catenary curve in the cable to de-couple the fish from the heave of the tow vessel. Don't bother with a davit unless you've got plenty of cable. In the minimalistic configuration I suggested, I'd tie off the cable at the gunwale as close to the fishfinder as possible - just watch where the cable trails so you don't get it into the prop when you turn or speed up. Don't kink the cable - use a cable grip or a couple of hitches with a soft bungee cord.

        Hope this helps.

        -Dan

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        • #5
          Dan
          Thanks again
          This will be a pretty low tec operation compared to what I think most on this site do. I think I will give it a try how ever just because that is the way I'am. Like you said I really got nothing to loose, and plenty I can learn.
          I like a little adventure so what the heck.

          Mac
          "Never Forget Which Way Is Up!"

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