Originally Posted by jgeissinger
If you used bottom paint on the paddle wheel, you painted it with paint containing metal. The transducer won't read the signal from the paddle wheel. Assuming you can pull it from inside of the boat, clean it of all paint and spin it by hand while someone watches the gauge.
I paint my RM paddle wheel (which is made by Airmar) with copper bottom paint using a q-tip and make sure the paddle wheel has clearance on the sides so it spins freely. I've been doing this for 23 years on various boats and never had a problem unless there is fouling from growth or a transient bit of seaweed while underway.
The RM/Airmar paddle wheel is a cast with a magnetic material--rather like some kitchen magnets use. There is no way metallic bottom paint will interfere with the sensor. At least in salt water, the bottom paint is absolutely necessary if you want the speedo to work all season.