Isolation... of the Electrical Kind

Our Isolation Transformer

As owners of a steel boat we have corrosion and with corrosion comes maintenance. There are two basic types of corrosion on a steel boat, the oxidizing kind and the electrical kind; the first comes in the form of rust (Iron Oxide) above the water line, the latter as electrolysis below the water line. Rust is unsightly, a never ending regiment of grinding, Ospho and paint being its only cure. Electrolysis can also be ugly but not seen until something goes very wrong! It is caused by the differential of DC potential and corresponding DC current flowing between two objects. DC electricity (which stands for Direct Current) like all electricity needs a path, the shore power cord supplies the path from our boat to the neighbouring boat. It is necessary to break this connection between our boats but we really enjoy shore power. So what is the solution? Isolation. Take away the connection to eliminate the primary cause of electrolysis and everyone is happy. To have the AC shore power and stop the destructive electrolysis it needs to go through something called an inductive coupling, which is exactly what a transformer does for us. We installed a nifty little ISO-G2 isolation transform made by Charles Industries and our boat no longer has a path for DC current to flow.

Divers Dream Zincs

After installing the ISO-G2 it was time to replace the zincs on our boat. These zincs act as sacrificial anodes to protect the steel and other more noble metals from the destructive forces of electrolysis. I knew that ours were getting a good work out and needed to be changed. Donning my scuba gear I went for a nice little swim in the cool water to discover I was right. Our boat uses "Divers Dream" zinc anodes and they are very convenient to replace while diving, in fact I didn't drop a single nut or washer while replacing five of these plates. Our old zincs were at about thirty percent of their original weight which is a bit low, the general rule is only to allow them to get to fifty percent before replacement. They had evidence of a lot electrolysis with a bright finish, lots of holes and their loss of mass.

Before the installation of the isolation transformer we didn't realize how much stray electrical current we had on our boat. I had put in a GFIC outlet in our pilot house a month ago, for the weeks following it would trip every five to thirty minutes. I was about to replace it with a normal outlet out of frustration. The same outlet has not tripped once since installing the isolation transformer.
For anyone who owns a boat in a "hot" harbour I would highly recommend the Charles ISO-G2 isolation transformer, it is small, quiet and runs quite cool. It is your best protection against the effects of electrolysis and for us cost about the same as buying new zincs, so it will pay for itself quickly.