NOT SO SWEET SOUNDS

My newly installed stereo system works great out on the water until I turn on the autopilot. Then every time the pilot makes a course correction, I hear a grinding noise on the stereo, at any volume level. Is there a cure?
Stan Panek, Dana Point, CA

Gordon West Replies

Autopilot drive motors are very noisy! Assuming the music is coming in from your MP3 device, the autopilot noise is likely coming in through the stereo amplifier power lead. Power lead filters are available from your NMEA authorized marine electronics dealer, as well as from all automobile stereo installation stores. A 10-amp filter will work fine on your stereo, but you may need a 20-amp filter to clean up the noise close to the autopilot drive motor. If the filters help, but doesn’t completely stop the noise, you may need to run your stereo system and its associated amplifier on a separate 12-volt battery with its own independent solar charging system.