Whistling Sail Drive

[ElEm30]

My 120S saildrive had the seals and diaphragm changed Apr 2014. A noise has developed between 1200rpm aand 1400rpmin forward. Sounds similar to a circular saw through wood although not as loud. Thought it was cavitation at first. No sound when on pontoon and driving forward. No sound with yacht on the hard and running in gear through the revs. Have read that it might be the prop 'whistling' through a build up of antifoul and the trailing edges having become out of shape/bevelled consequently the prop is not balanced. Anyone any ideas or suggestions please? Have an old prop I could try but of course lift in and out expensive.

 

[philip_stevens]

The whistling is due to the trailing edge. You are probably correct in blaming a buildup of fouling.

I was on a containership (many moons ago) that had severe whistling at certain revs. The remedy was to grind some edge off of the trailing edge. This was done by erecting an underwater biome over the prop. Air-tools were used to grind the metal off, and consequently, the whistling stopped.

 

[ElEm30]

whistling saildrive

The whistling is due to the trailing edge. You are probably correct in blaming a buildup of fouling.

I was on a containership (many moons ago) that had severe whistling at certain revs. The remedy was to grind some edge off of the trailing edge. This was done by erecting an underwater biome over the prop. Air-tools were used to grind the metal off, and consequently, the whistling stopped.

Thanks Philip
I'll clean the prop down to the original finish, use spray-on antifoul,
and keep fingers crossed when I launch next year.