Speed Sensor Fouling

Fouling is a constant problem with the paddlewheel speed sensors. I know it is possible to pull the sensor internally while in the water, have water come gushing inside and insert the plastic plug. Then the paddlewheel can be unfouled and later reinserted. I am worried about the amount of sea water that will come into the boat. Can anyone comment on this procedure?

Some water does come in but manageable.

Airmar does supply a rebuild kit. I believe they recommend rebuilding with new paddle wheel every 5 years. They also recommend painting the paddle wheel and housing with water based anti-fouling paint designed for transducers. When not in use for an extended period of time, they also recommend removing the paddle wheel and using the plug.

Please refer to Airmar website for details.

I have done that once. It was "interesting". I was as prepared as I could be, had the plug insert at the ready, towels, bilge pump to auto.......I pulled the sensor assembly out and was immediately mesmerized by the view through the hole. It took me a few seconds to recover, but I inserted the plug, tightened it down and cleaned the paddle wheels. The reverse process went a little smoother.

That said, I was told by an old timer at our club many years ago (and after the above experience) that the best way to keep the little critters from starting families on the paddle wheel was to clean it, then use a Q-tip to put a thin layer of marine trailer bearing grease on it all over the surface. I have been doing that every year and have had no issues with fouling.

More noise than water: I do this a few times a season and take in less than a gallon of water each time. Just make sure you have the plug at hand; mine's on a tether to my wrist so I don't lose it in all the excitement. That said, I did practice while the boat was on the hard over the winter. Good luck.

Michael Luskin
"Turtleheart" IP27-146
Scarsdale, NY

I did try pulling the sensor and installing the plug. A little surprised by the amount of water but it was probably less the 1/2 gallon.

I leave mine out and use the SOG from the GPS. When I race and want to see how much current is affecting me, I stick it in. I may have to try the bearing grease option. The water coming in on older transducers without flapper valves when removing/installing the transducer is alarming at first, but the water entering the boat is minimal.