Autohelm ST50 Plus Tridata

[Agriman]

The speed and log indicators stopped working. I assume the paddlewheel has been blocked with debris. Is this an easy dismantle and clean while in the water? I have a "plug" chained to the transducer but am concerned with needing O-rings or other parts while trying to re-place. Anyone done this with success?

Thanks

[km1125]

Even if you didn't have the o-rings, there wouldn't likely be a lot of leakage if you get the plug back in there while you're inspecting/cleaning the wheel. You should have plenty of time to work with it while the plug is in there. If the plug has o-rings on it, that should seal tightly. You can swab some Teflon grease or other lubricant on it prior to pulling the wheel out, so that it slides in easily.

[Viper]

Ya I agree with km. The thru-hull likely has a check valve in it that will close when you pull the transducer out. It's not completely water tight but keeps most of the water from coming in for the time it takes you to insert the plug. Proving the plug still has o-rings on it, it'll be water tight and can stay that way indefinitely until you service or replace the transducer. As km said, lubricate the o-rings before re-installing the unit.

[Agriman]

Thanks for the encouragement, I am concerned as to how easy the thing will come apart after 22 years.

[km1125]

Legitimate concern about trying to get it apart. Wiggle it around gently as you're pulling.. there might be enough spring in the O-rings to loosen up any debris that might have worked it's way in there which would resist attempts to pull it out.