Galvonic Isolator

We had one on a 50 Viking Sport Cruiser (Princess). It was installed back by the main electrical panel in the stern. DK much about them, but I can tell you that we had our zincs changed every year and they had plenty of life left on them.

I always fit this type right next to the inlet if I can. It'll pay for itself over the years, regarding anodes.

Aquafax » Marine & Industrial Equipment

1995 355 Installed in elec panel

I installed one on a boat that had a problem with zincs eaten up in a month or two.....They now last 6 months. It was installed on the green wire (50amp), right where the shorepower comes into the boat.

Big thumbs up for using the model with a meter. Knowing that something is wrong helps a lot.
Fixing the electrical problem before it sinks the boat is the rest.

Galvanic Isolator

Below an example for the installation of an galvanic isolator. The brand is not important, but the warning and installation advices are nice. I would combine this installation with an indicator for correct polarisation (of the shore cable) and a soft start, to prevent early tripping of very sensitive breakers. Also for a metal hull boat, I would install an indicator for the warning of "current on the hull", as the fault can be in the boat (Especially, when you do a lot of work on your boat yourself ). All this stuff is available on market and very easy to install. Here in Europe, the Dutch company Mastervolt is one of the biggest player on this market for normal sized yachts.

On my earlier (smaller) sailboats, I always had two shore power connectors. One with the above mentioned equipment for the house power and a second connector with isolator and input rheostat (charging current limiter) directly and exclusively connected to the 3 battery chargers (one 24 Volt house power, one 12 Volt navigation equipment and one 12 Volt for the starter batteries). With this second connector I was able to use weak or bad (sinus) shore power sources with all kind of voltage and frequencies. AC was then produced through the inverter bank. Combined with the automatic inverter / shore power / diesel generator switch and automatic generator start, this system was almost idiot prove and worked on several boats flawlessly for years.

With todays DC or variable speed Gensets and Inverter arrays, things are even much more easy.

Having not dealt with a G.I. before the VSC, what initially threw me was the missing leg on the 50 amp shore cord. I arranged with our yard for a new cord and they were set to install until I got a little more education. Apparently I wasn't the only one unfamiliar with them.

LOLOLOL, many many years ago I replaced the end on a Hatteras 50amp shorepower cord because the flat blade was missing from the plug and I thought it fell out or got pulled out. I then realized that it wasn't supposed to be there after the fact. I felt really stupid once I realized that.

This is a prime example of why I never try to bluff my way through things (as so many dO). If I don't know something I'll admit my stupidity and say I don't know. Invariably I find that the next guy, whom I assumed knew more than me, doesn't know either and we both learn. The beautiful thing about boats and this business is that there is always something new to learn.

I even recall reading something in my original 1984 Bertram manuals about the grounding system and NOT having a ground or something like that. I need to take a look at that. I have a couple of Galvonic Isolators that have not yet been installed on my Bertram 54 ... but it's on my list. And I will have the professionals install them!

It's those pencil zincs on my engines that seem to get eaten up the quickest. Sure would be nice to increase the lift of those.

Great subject.