Switched the wire topping lift
to a small diameter Dyneema
line. Fist time we got any wind, had this obnoxious bass hum. Looked all over the boat for a day or two without being able to locate it. Happened to tug on the boom and the sound changed pitch
. The Dyneema
line makes a good guitar string. Will replace the very small diameter line with 3/16" line one of these days to see if that eliminates the hum. Fortunately, the wind has to be blowing 10k or more and the topping lift taut for it to sing so no problem sailing.