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Mounting height for T8

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  • Mounting height for T8

    I am installing a T8 as a kicker on a Grady-White 228. I know the general rule of thumb is to install an outboard so the cavitation plate is even with the bottom of the hull. However, the manufacturer of the *****ing motor mount suggests the motor be mounted where the plate is 6" under the water surface. I have some interference problems and would like to mount the motor a little higher. Any suggestions on minimum depth on an istallation like this?

  • #2
    If the engine is not deep enough, you risk overheating it as the water pick ups are not low enough.

    Have you tried the adjustable motor brackets?

    TMD

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    • #3
      Typically with motors that push boats to planing speeds, for best performance, the motor is mounted such that the Anti-Ventilation plate is even with to as much as an inch or two above the water flowline (hull bottom) where the motor is mounted on the transom. The reason for that is that the higher the motor is mounted, limited by the prop's ability to get purchase, the less drag you have, and the water cooling pickups are all below the AV plate. If you are using your T8 for a kicker, you are not going to plane with it, so there will be cooling water all over the place almost no matter what height you set it at. The issue that does evolve in setting a kicker too high is that the bite of the prop if it is above the bottom of the boat, is not in clear water so performance suffers, and it suffers even worse in reverse; the thrust of the prop would then be short circuited by the transom.

      If your AV plate is about even with the hull bottom at the location where the kicker is mounted, you will be OK in all regards, no matter how far below the water line that happens to be.

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      • #4
        p.s.

        You'll love that T8 if you decide to go that way - I put one on my BW Outrage 22 and I couldn't be happier.

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        • #5
          Hi Kingfish! Thanks for the come back. I think my T8 may be less effected by it's heigth relative to the transom than most boats due to the type of mount used. I am using an extended mount similar to that used by Grady on the main 225hp 4 stroke Yamaha. This mount places the mounting point for the T8 30" back from the transom. Incidentaly, I am installing a Nautamatic Marine TR-1 fully programable wireless autopilot on the T8. I should be a great help when *****ing big water.

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          • #6
            There is a rough rule of the thumb (again, on planing boats) that for every 10" of setback, you can raise everything another inch. 30" back = 3" higher, everything else being equal.

            I like your idea of the remote control - I have my T8 rigged just like a twin to my Evinrude 225, with full helm control for everything: throttle, shift, ignition, steering, gauges etc. Once I install my SportPilot Plus autopilot, I'll be in the clover too....

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            • #7
              That will be a nice rig. I to will be able to control from the helm. I am replacing the origonal single control with a dual setup. However, once the T8 is in gear, I will control it with either the programable wired or wireless control of the autopilot. Thanks a lot for your input.

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