What Lurks Below?

One of the most difficult parts of the boat to maintain is what sits below the water. It’s hard to see, and what issues might exist, are not a weekend project for most boaters. What goes on below your boat is crucial to your vessel’s maintenance and upkeep. Worn bottom paint can lead to growth, which can greatly increase fuel costs. Galvanic corrosion from things such as errant current seeks to corrode underwater metals like props and thru hulls. And what went bump in the night on your last cruise may have left a bigger mark than you think.

Galvanic corrosion may be the most difficult issue below the waterline to manage. While boats in salt and brackish water are most at risk for corrosion, the risk exists for boats in freshwater as well. This type of corrosion occurs when two differing metals are submerged in an electrolyte, like saltwater, creating an electro-chemical reaction. This reaction results in the corrosion and breakdown of one of the metals. Most of us know the disastrous results this can create on boats.

Stray current corrosion and galvanic corrosion are similar but different. Galvanic corrosion is an electro-chemical reaction between two dissimilar metals. Stray current corrosion occurs when an electrolyte conducts a current. This can occur from