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Three weeks ago I had a full bottom job done, including all running gear painted with two coats of Interlux 2000E epoxy, followed by three coats of Trilux. The running gear paint recommendation came from another B33'er in South Florida who had similiar problems with severe gear fouling in our tropical waters. Did the same for all the thru-hulls. I had the props done with Mussell Buster coating for similiar reasons. The hull got sanded and a single coat of Trinidad Sr, a coating I've had good luck with in my particular part of the world. When all this was done I was quite happy, expecting to get another 18 months of worry free life out of the bottom.






I ran out some fuel and noticed on the high water line that some paint was gone from the hull, about seven days after she splashed again. Contacted the boatyard and they put me on the schedule to bring it in for a haul and a look. We did that today. What I saw was an absolute horror.

I don't have any yet but I'll post current pics tomorrow. In short, half of the white Trilux on the running gear is gone, mostly on the struts and rudders. Some spots of the Mussell Buster are gone from the props.

Still not sure how to test a galvanic isolator but will learn tonight. Am also heading down to the dock with a silver chloride reference electrode to test the water, but doubt I'll find anything that will get me anywhere. Also plan to test the grounds on the shore power at both my slip and the one I spent the two days in.

I have to find the source of this before I put her in the water again. Any ideas?

Sean,
If you had not been having problems and then suddenly you do and the only two things that changed were slip and bottom paint then I would look at the slip.

If it was bad bottom paint, you wouldn't see the zincs degrading.

I suspect the temp slip you were in had a possible reverse polarity problem or more likely when the conduit was submerged, you had leakage current into the water.

You don't mention the name of your galvanic isolator. They can range from simple resistor style to isolation transformers.

Can't tell you how to test without knowing what you have.

If the isolator was bad and you had leakage current, that would do it.

Sean,

I noticed that there was no shaft zincs on your boat. Do you not use them down there?

DQ

Check the wiring of the bilge pumps and such. It is easy to wind up with the switch on the ground side, in which case the pump stays "hot" and wreaks havock with the bonding system.

Bruce,

It is a "quicksilver" isolator, the type with a capacitor. I figured out how to test it from Nigel Calder's book and will report on results. I intend to install an isolation transformer and be done with the problem and worry for good. Any recommendations/sources for two of those? I want to install two separate units because I have two 30A shore power curcuits.

I dont see how the power would take off the paint I would think that it is something else humid weather or something with one of the paints.

Sean,
You are in luck, I have a brand new Charles Marine 30A Isolation transformer that I purchased and never used. It is new in the crate and I'm ready to make a deal. Make the deal nice enough and I'll even donate the proceeds to this site.

Check out Charles Marine

http://www.charlesmarine.com/main/ma_iso_bost.html

I'm installing one 30A isolation transformer for each shore line. Should never have this sort of trouble again after that. Found some cheap ones on sale at defender: http://www.defender.com/product.jsp?pat ... &id=614224 (have to copy and paste that link, for some reason the whole thing doesn't come up as a link).

Chiles lets make a deal. Shoot me an e-mail at SBurlingham@cfl.rr.com or give a call at 321-723-7285

Sean, you can always try this: http://www.tinyurl.com/ for those long web addresses.

Like so: http://tinyurl.com/p5jbr

That tiny url trick is neat. I wonder how long the tiny links last.

Well Defender.com pulled a fast one on me. I ordered the two isolation transformers, then called two days later to check on the order. Girl says "oh yeah, I see the order here....they will ship January 2007." What? I tell her I need them ASAP, ask her to call the manufacturer. I hear back a day later, and the earliest I might get them is November. Why they took the order I'll never know, they were always good to me in the past.

Hate to do it but now looking to We$t Marine for two of these, or perhaps going back to a galvanic isolator. ABYC now requires those to be monitored with LED's to alert for failures, so at least I'll know at a glance if it's doing its job. Sure would be a lot easier to wire than re-working power leads for the transformers. Hate to take the lazy half-assed way out but want this done. Bad part is the new ABYC-compliant galvanic isolators are almost as expensive as the isolation transformers advertised on defender. But I don't like the idea of leaving the boat in the water for weeks on end without shore power.

Chiles I'll still take the one you have off your hands if I can get ahold of you. Shoot me a message guy

Sean

Try calling Consumer Marine Electronics in NJ. I can't find the number right now but they have been pretty good to me in the past. You should be able to find them on the internet. Tony Meola

Sean,
I really suspect either you have 110V in the ground circut or 12 Volts probably coming from your boat. I have one of those three light polarity checkers always pluged in to an outlet. Usually it is the 12V to ground from a bilge pump switch that causes the trouble. Since you have some arcing in the 110V I would get that corrected. Caldors book gives you all the info to check things out.
Good luck

Tony I tried their website already and no isolation transformers listed at all. I'll try calling them too just to be sure.

I spent 4 hours yesterday morning with the silver/silver chloride half cell overboard, looking for stray currents coming from my boat. Everything (and I mean everything) checks out perfectly. DC voltage between grounding/through hulls and Si/SiCl in water is 960-970 mV, meaning that zincs are doing their job just right. Every thru-hull and piece of metal in contact with the water registered the same reading, with the exception of the A22 shafts which read a little lower at 955 mV. That is curious but I think due to their low corrosion potential relative to bronze. The readings didn't change with every DC accessory on (checked each one by one then with all on too).

Then I hooked up shore power and ran same tests on all DC and AC items - no changes in readings. Then I ran genny and again tested everything- no changes. Then ran genny again with shore power connected too (never actually do this in practice) and still everything checks out good. One thing I forgot to do was to run the main engines, which would check the alternators on those, but everything else checks out okay.

The good news is that my boat is not throwing any currents. Unless I find something with same tests with the main engines running, my electrical and grounding systems are perfect. It's been an education.

Sean,

A bunch of years ago, we were chewing up zincs every three weeks. We eventually found a bad bilge pump. I had 1.5 volts coming being thrown off. We found the bad pump using an ohm meter. We had to first shut everything down and disconnect the batteries. We hooked the ohm meter up to the battery leads and slowly started to turn everything on and off. When we got to the rear bilge pump we had a 0 reading. Changed it and that solved the problem. Tony Meola