When we bought our J/109 we had the prop and sail drive leg coated with PropSpeed® by the boat yard we store at.
It was now been three years with six month sailing seasons since then and the coating is still doing well. The photo above shows the amount of fouling when the boat came out of the water this year after six months, and the little bit of light shell came off with a scotch pad and very little work.
That said, there are some small areas of coating failure but close inspection shows that there are places where the applicator did not get a quite even coating thickness.
Prop Speed success depends on prep and application. The use environment water is also a factor. Mine was yard applied ( who knows how.). It lasted three seasons in the mid Chesapeake Bay but the condition wasn’t nearly as clean looking as your picture. I tried Rustoleum galvanized (93% zinc) this year and had a good result for the cost of $18. I removed the prop speed with paint stripper,then sanded the PYI clean,sprayed three coats and done. A lot cheaper and not hard to DIY. But those of you with saildrives suffer unique neurosis. Mike Pitzer