Zinc is a very soft metal. It has many uses but, in boating, zincs are necessary for the safety of the boat. Why??? you ask. I’m glad you did. Electrolysis is stray electric charges in the water (for ease of explanation). This electrical charge attacks metal, such as the running gear on a boat. The way to save your running gear is to attach zincs to the metal parts (shafts, rudders etc.). Electrolysis attacks the softest metal first and will eat away the zincs and not attack the harder metal of the running gear. In some areas of the St. Johns river, you can go through the zincs in a month. The running gear in the picture is an example of what can happen when zincs are neglected for a long period of time. The running gear had to be replaced for a cost of over$20,000. Zincs for the boat would have cost about $150.00. I don’t think I need to show the math.
Another thing to consider is that the engines also have zincs in them. The water is running through the engine and out the back, completing the circuit. The headers and cooling system could look like the running gear in the picture if you don’t keep the zincs up. Add another $8,000 to fix that. There have been a number of times I have seen boat zincs kept up and changed religiously but the owner did not not know the engines also had zincs.
This is a real life example that occurred recently. The current owner bought the boat without a survey. Both owners were first time boaters. The damage was found when the out-of-the-water survey was done. Needles to say, our buyer decided against he purchase. The $700 survey save him $28,000. Watch out for our next blog on surveys and why you need them.
Think Twice about Zincs, it could save you money and your life.