|
• Shore Power •
Another common cause of excessive corrosion is the problem faced while connected to shore power. Typically AC power at the dock contains three or four wires. One or two of these wires are the hot wires. One is the neutral wire and one is the green or bare ground wire. On the boat, the ground wire is bonded to all of the major metal parts, engine, running gear and plumbing of the boat. The problem arises because every boat in the marina is also using the same ground wire to bond its metal parts. Now here we go again, we have taken two or more dissimilar metal objects, electrically bonded them together and immersed them in saltwater. Sound familiar?
 |
This situation can be avoided by using a simple device called a galvanic diode isolator. The diode isolator lets AC current pass but blocks the small-unwanted DC current generated by the bonded, immersed boats. You can buy these isolators at many dealers. Even if you dont have a problem at your marina, you may stay at a marina that does have a problem. Zincs can be eaten away in a few weeks in severe cases. A diode isolator is a cheap, easy investment. Just be sure when boats that have onboard generators are involved, the grounding bond from the generator is connected on the inboard side of the isolator.
Of course, we use sacrificial zincs or alloys to help with the problem but if the current generated between the two boats is excessive you will be replacing a lot of zincs or damaging your propellers, shafts and rudders.
|
