Installing ground/bond wires

[westcoastcat]

Loren thanks for the reply, so from your comment I take it you're saying the lack of a ground cable will not cause the blistering?

The keel is lead and it appears that pockets / blisters dime to quarter size have appeared on the keel and the vicinity of the keel on the hull.

The surveyor(s) two have surveyed the boat can not come up with any type of agreement, they both say on one hand it could be this on the other hand it could be that, I think the next surveyor I talk to should have less hands ( thanks Harry Truman ).

 

[Emerald]

had a single very large grounding wire that went from the engine to a keel bolt, this wire had corroded off the keel bolt and per the surveyor this caused "galvanic corrosion" - basically the keel and hull around the keel blistered, the fairing material - cabosil on the keel and hull blistered.

The wire not being in place would not cause galvanic corrosion, but the wire corroding away to nothing could certainly have been a symptom of galvanic corrosion. The causes of the corrosion could come from many sources ranging from stray electricity in the marina if the boat spent much of its time on shore power to a lack of proper zincs on the boat itself. As to the galvanic corrosion causing the blistering, I find that hard to swallow. The only way I can see that occurring is if the corrosion was so severe that the metal underneath the fairing material became so corroded that it was starting to break down/slough off, turn to dust etc. This would seem to me to be unlikely without a lot of other visible corrosion activity all over the place and all around the keel - I'd think the keel bolts would have to have basically been eaten away before you'd have reached this point. I'm more inclined to think the blistering is unrelated and tied to poor application of the product or just age. Any pictures of the area? Pictures of the area in the bilge and externally on the keel would be helpful in seeing what is going on.

 

[westcoastcat]

These are some pics, the boat is a fresh water boat but will be moving to salt water when the bottom is done.

 

[Emerald]

This is looking to me like we're seeing the faired spots of a prior blister repair job where there has been an adhesion issue and the repair/filler material has started to loose adhesion. I see what looks like metal in the worst spots, which makes me think that the original repair attempt went down to the metal of the keel and has suffered an adhesion issue. There are so many reasons one could come up as to why it didn't stick as to make it probably pointless to speculate without more knowledge of what was done. I know I'm arm chair quarterbacking on this, but one possible approach is to physically poke at each spot, and if the material is sound, leave it alone, if it's not stable, grind it out and redo the spot, and then just make this part of your annual maintenance routine of working on spots as they reveal themselves. Depending on why it has lost adhesion, i.e. poor preparation, some spots may be fine while others failed.

Of course, this advice is worth what you paid for it....

 

[westcoastcat]

The prior owner hauled this boat about three weeks ago, did a quick scuff and was about to put on new bottom paint for the sale, I stopped him so I could see the hull prior to slathering with bottom paint, glad I did. The first surveyor recommended stripping the entire hull below the waterline and the keel and re-glassing the entire bottom, and just fairing and painting the keel. The second surveyor recommended sanding bottom grinding out and filling the blisters as required then new barrier coat and bottom paint saying the bottom does not need to be re-glassed. Looking at the pics what do you guys think out there. Last haul out prior to three weeks ago was 2002.

 

[mherrcat]

Trying to understand this...

So connecting mast/shrouds to a keel bolt works even though the hull is barrier coated and has bottom paint? You don't need some kind of bare metal in contact with the water?

 

[Michael Edwards]

Westcoastcat, that looks alot like the pox that was on my E-32. I sandblasted the bottom, then spent two days using a Dremmel to grind out the small and shallow bisters. After allowing the hull to dry completly,we epoxy filled and faired her. Followed by two coats of epoxy resin then two more of barrior coat. This was about eight years ago. no more blisters have occured.
My brother, who built many boats explained that the lay up scheduel was to blame. Many builders would lay in the second or third layer of glass dry, followed by wet. This implies incomplete saturation of that layer could happen. This makes some sense in the case of my own boat, because none of the blisters were deeper than the second layer of cloth. This observation is anicdotal at best, but I agree that grinding out the blisters and filling and fairing, followed by barrier coating is the right approach. To reglass the bottom might cost more than is reasonable. As a DIY'er, the yard doesn't make much from me. Also I've seen some pretty shoddy work being done by some yard employees. Reglassing is MAJOR work.

 

[westcoastcat]

Michael, thanks for the info., I am still waiting to get the boat out to me, currently a fresh water boat inland - could get it done there, probably for less $ but too far away to watch how well the job is done.

 

[bayhoss]

Lightning strikes

Found this article. It may prove worth reading. If its been posted , sorry for the repeat! www.kp44.org/LightningAndSailboats.php

Best,
Frank