Anti-fouling for props
Not required for fresh water. Here on the Chesapeake,
* Zinc spray, works okay, relatively inexpensive, is good for the prop. It is mild antifouling, but it mostly seems that growth does not stick very well to it. So if the boat is not used, it will foul up, but if used regularly, the zinc will shed what growth accumulates between uses. $50. Can be reapplied easily with minimum preparation. Can be applied during a short haul.
* PropSpeed and various other similar products. Works great, but high price, high maintenance. ~ $500 per prop. Usually good for a year or two, but needs to be completely stripped to redo.
* Antifouling paints work good of course, but have a hard time sticking to bronze and the ones with copper are harmful to the prop alloys, so for both reasons, and epoxy barrier is required. The barrier required sandblasting. This system also runs $500 for the initial application, but can then be painted with new AF for 2-3 years. Eventually, the epoxy starts to chip off at which point it is time to strip it and start over.