I am also curious about Barnacle stop. Seems
Like it's easy to apply. I am getting the houseboat out of the water this week for cleaning and may try to treat drives, props, and intakes with this stuff.
I was also considering doing this to our outdrives and intakes next winter, but I haven't used it yet. From what I've found, Barnacle Stop is just capsaicin (the component that makes chili peppers hot) infused wax that prevent the mussels from attaching. Last time out at Bullfrog, I noticed that the docks and their support cables didn't seem to have much visible mussel growth and I'm wondering if that has anything to do with a protective film of algae preventing mussel adhesion? It also could be that the mussels just hadn't moved in yet and it will be worse this summer.
If this product is just relying on preventing adhesion of the mussels, I'm not entirely sure if the capsaicin is necessary. This article states that it "performed better" than surfaces treated with only wax, but that statement isn't qualified and no pictures are included. If I do use this product, I may also do a test patch with just paraffin wax and see if it generates the same results; it's a whole lot cheaper.