Hello I’m a new member, but I saw what you were saying of the prop fouling I had this on my last boat in Med waters and friend told me to try Lanolin? So I got a big tub from the chemist and plastered it on. It seems that as the sheep have this to protect them then I thought it might work. It is really really thick like tar. Now I thought with the prop it would wash off it did but in about 5 months into my season as I was checking it with a mask. I have to say I use it all the time now but it is a bit had to find. Anyway might help as a usual fix.