Just to add to this thread, I was shocked on the build up on my propeller from last year. The coral worm build up is shown in the first photo.
In Chichester Marina they recommend
You have to sand the propeller first after usual wash off, the manufacturer recommends 80 grit using a sander, but I found it was best using manual sanding. In the UK the distributor says not to use acetone to wash down the prop.
You then apply one coat of primer, followed by two of top coat.
I Will monitor how it looks over the season.