Grounding problem ?

[WALTER GURAVSKAS]

The boats back at home for the winter,(hope it's short) A few weeks ago the person in the slip next to me had a survay done on his boat, the gentleman doing the survay pointed out to me that i may have a problem. My bottom paint is black, at the water line there is a green film (does not wash off) it is all around the boat ! He told me that this green film is caused by a through hull corroding. Has anyone ever come across this problem before. I plan on going to a book store to find a book pertaining to a boats electrical system. the boat is a 1984 10 meter express.
Thanks in advance..

[captainmaniac]

I have never heard of or seen such a thing caused by corosion or bad ground. Metal parts may disolve, but on a fibreglass boat you don't get 'ring around the collar' when it happens.
I would suspect the film is more likley a stain from some crud that was pooled around the boat for a while, or perhaps some kind of chemical reaction between something you were surrounded with and your bottom paint.
You may want to check into the credentials of this surveyor before you put too much faith in what he is telling you....

[prowlersfish]

Ever seen copper turn green ? and your paint has what in it ? also some growth is green and it just won't wash off.

[gjrylands]

The surveyor saw something that made him suspect a problem. He went out of his way to inform you. Don’t just blow him off. I would take his advice and check the system. If he is correct and there is problem I believe it isn’t with the ground, but with the neutral in the system. Power needs a complete circuit to operate. Power coming in must have a way out. In the power panel the ground and neutral are connected. The ground is connected to the engine blocks and many other spots in the boat. If there is a poor connection of the neutral the power will exit through the ground. The poor connection could be in the panel, in the shore power input of the boat, at the dock receptacle, or in the dock wiring. The poor connection might produce heat and can show up as a burnt or melted terminal on the plug or receptacle. It could be in the dock wiring and not be visible.

If the boat is out of the water for winter you can check for signs. If there are zincs on the boat, check them for disinigration, check the props and look for a blackish spotting or pitting on the edges, and check the through hull fittings for pitting or discoloration. These are indications of electrolysis. A further test that can be done, with the boat out of the water, would be to plug the boat in. Plug something into one of the receptacles that has a heavy draw like a space heater. Take a voltmeter and see if you get and voltage reading at the prop or shaft. (For this test the boat can’t be grounded by the stands or other grounding sources.)(If you Get a reading it would indicate that current is leaking through the ground.) Current leaking through the ground would cause the copper in the bottom paint to turn green. Another test would be to plug the boat into a GFIC outlet. (Again the boat can NOT be grounded; the GFIC will trip when a load is applied if there is a problem in the boat.) Again this would mean power is leaking through the ground. These tests are checking the boat, not the dock wiring. The boat could be fine, but the dock or cord could still have a problem.

One needs to be very careful with electricity around water.

[RWS]

These boats are 20+ years old.

Take nothing for granted whatsoever, especially with the electrical system.

I found solid wire roamex and wire nut connections to my factory cockpit wetbar. This covered all the outlets, referigerator and icemaker. We melted the outlet, lucky it wasn't anything more.

I'm only the second owner of the boat and the only thing I can figure is that it was done by the selling dealer in the yard.

You should consider a through check out of your electrical system as well as the bonding system.

A bad ground, rubbed through wire or other issue could cause a catastrophic failure at sea, READ AS FIRE.

It's really best to take no chances.

And while we're at it, many of the 80's Trojans had toggle switches that were also BREAKERS on the 12v side of the panel.

In many cases these have been replaced by unknowledgable owners (like me) who found toggle switches already there and replaced them with similar switches.

These are all supposed to be toggle switch BREAKERS. I found this out by accident once when one of them tripped due to an overload on a quiet day and I happened to both hear it and see it.

I confirmed it by checking out the schematic.

Something additional to check out.

BE SAFE!!

RWS

[TADTOOMUCH]

I agree with RWS above. I have a friend who had a new Searay that had the fridge installed wrong and they pinched a wire to the power cord behind it and the boat burned to the water line during the week when he was not there and took out two other boats. Get a good marine mechanic who knows electrical and have it checked. Your zincs on your prop shafts will look like crap if you do have a stray current issue. But do get it checked.

[Danny Bailey]

Green ring or not, I've said it several times before and I'll say it again....if you still have the original Groco through hulls on your Trojan, you are tempting fate for an 'at the dock' sinking or worse yet, an 'underway' sinking.