It would have to be a fairly extreme situation for your zinc to have depleted and serious damage to your running gear occur within 5 months. Not that it couldn't happen, but it would be unusual. You are probably fine. I don't know what diver rates are like in your area, but here it would cost you in the vicinity of $50.00 for an inspection. If your diver is reasonable (like me
) that price would include the installation of a zinc or two (zincs would likely be extra). Couldn't hurt to carry two on your shaft instead of one, BTW.