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Electronics upgrade

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    Electronics upgrade

    Mates, I have just upgraded my electronics, Broadband Radar, NSS7 evo2 MFD, and Autopilot. I'm having a problem with the choice of tranducer.
    I had the Totalscan from Simrad, had the boat hauled and to my dismay, there was no place to place the skimmer style transducer on the Transom.
    Can anyone suggest a type of shoot Thru Hull or Thru Hull transducer that will be compatible with this setup? Much appreciated in advance.

    They offer many compatible transducers with that unit.
    look into their forward scanning sonar,
    provides a maximum forward view of eight times your current depth,
    Joon, Kathy, Jaden & Tristan
    Uniflite 42 AC, DD 671N
    93 3058 sold
    92 2855 (day boat)
    91 Fourwinns 205 (lake boat)
    Longbranch WA
    Life is Good


      The high resolution StructureScan imaging (downscan and sidescan) needs the longer Totalscan transducer. It's actually multiple transducers spaced along its length, and uses the slight difference in sound arrival times at each individual transducer to generate the high-res image. (Like a phased array radar if you know what those are.) If you use a regular thru-hull or in-hull transducer, you'll lose StructureScan (455/800 kHz) and only get the regular sonar and CHIRP (83/200 kHz, down only). If you're not into fishing, this may be acceptable. Airmar produces most of the high-end transducers used by Navico, Garmin, Hummingbird, and Furono. The exact model depends on your typical water depth (how many Watts of power you want), how narrow or wide a beam you want, angle at which you're going to mount it, what frequencies you want, if you want CHIRP, and how much you're willing to pay.

      But since you paid extra for a Totalscan trannsducer, I assume you want to retain StructureScan. Navico offers a thru-hull version (with fairing), but it has to be mounted low enough to "see" sideways past the keel of your boat (i.e. close to the centerline). It's also StructureScan-only (455/800 kHz), so you still have to buy a second 83/200 kHz transducer (and I believe the recommendation is to mount them within 1 ft of each other). The whole point of the Totalscan skimmer transducer is that it combines both of these into one unit.

      A few people have mounted the Totalscan skimmer transducer pointed forward, mounted on the transom but running underneath the hull instead of trailing behind it. The only real challenge is figuring out a way to make it sit horizontally on the angled hull bottom, and low enough to "see" sideways past the keel. One person modified a thru-hull transducer fairing. Another built up a layer of filler material and reinforced it with epoxy I think (can't find the link for this one).

      There's a setting in the MFD to reverse the direction of the Structurescan image if you mount it pointing forward. So left/right and forward/back will be correct. The main drawback of mounting it pointing forward is that it's vulnerable to a debris strike. The skimmer mounted backwards is designed to kick up and out of the way when struck by debris. If you mount it pointing forward, you lose that protection (it would kick down and be torn off by the debris). I considered a fairing and a Transducer Shield or just a rubber deflector, but decided to try it mounted backwards before throwing a lot more money at the problem. I lose a bit of the shallow angle image to port due to the shadow of the sterndrive. But it worked a lot better than I expected when first eyeballing it, and I've decided to justrun it that way.


      The only real advantage of a thru-hull or below-hull (pointed forward) setup would be a clean sonar image at higher speeds.
      1994 2556, 350 MAG MPI Horizon, Bravo 2


        Thanks roughryder, and a tip of the hat to you Solandri, quite a bit of info!!


          I know Garmin makes a fairing you can adapt to a transom mount transducer, it depends on the shape of the transducer.
          I am using 3 transom mount transducers and this spring will use 3 of the fairing to mount then under the hull.
          They do work quite well in the wet keel of my 3870 though.
          Pat says: DO-IT-RIGHT THE FIRST TIME!

          Bayliner 3870 "ALASKA33)
          Twin 350 GM power
          Located in Seward, AK
          Retired marine surveyor