My long shaft Tohatsu 6 worked pretty well but the zinc is so little that it was useless. After about two months on the mooring it was gone. This year I put bigger zinc by drilling through the captivation plate. At the end of the season I was bringing the boat over to the marina in a 30 knot wind when the motor failed (it kept running but raced as something went wrong with the prop or lower unit. It looks like the lower unit corroded through in a pinpoint hole. The bigger zinc method worked with my old outboard for 10 years so I'm not sure what happened. Looks like a $500 bill to buy a lower unit . . . not what I was expecting.