Installing a Boat Lift - Avoiding Electrolysis

We are finally getting the much anticipated boat lift installed. I've learned that there are a lot of differences between taking care of a boat in salt water as opposed to the fresh water lakes of Tennessee. The primary concern is corrosion. Since salt water is such a good conductor of electric current, a boat tied to a dock essentially becomes a floating battery. Dissimilar metals in the water will produce voltage with either a positive or negative charge. Current will pass back and forth causing electrolysis which results in severe rusting and pitting. To minimize this, salt water marine components use sacrificial anodes called zincs. The zincs are placed near the prop, outdrive, trim tabs and other components. They're designed to conduct electricity better, thus drawing the current away from other metals. Since they corrode quickly, zincs have to be replaced every couple of years, or even more often depending on the level of salinity and whether the boat stays in the water. Even with good zincs, you still get some rusting and pitting. Our solution has been to put the boat on the trailer when we don't plan to use it. But, I really like to have it on the dock for those spur-of-the-moment fishing or cruising trips. That's why we need a boat lift. It works like a float-on trailer utilizing a system of cables and pullies to lift the boat above the water. Considering the wind and waves we get, it's even more important on our dock. Unfortunately there's a big backlog of dockowners in our area who want to get lifts installed. We've been waiting since April. If things go according to plan, the lift should be installed by this weekend. I'll put up a picture when it's finished. -S