When I hauled my boat, the Fall of 05, my zinc was completely worn away. I believed the problem to be a 36' power boat just 3 slips away. This season that power boat did not go in the water. I added a shaft coller zinc to double up. The last thing I wanted was damage to my Max prop. The other boats at the dock have reasonable zinc wear. This Fall I had the same deterioration. I heard that a galvanic isolator might solve the problem but do not know which one (BRAND)to buy. Any ideas and additional measures that I can take would be appreciated.