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Old 28-08-2014, 12:21   #1
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Galvanic corrosion or Stray current? NEW PICS!!

I've uploaded a new photo album! Please look for a superhero in my profile...

I only learned my title's terminology today in relation to what is not the the umbrella term called "electrolysis." I'm leaning towards stray current damage, but I'm new to all of this. I have a spare prop, but could use some help from here and a Floridian company with expertise. I want to fix everything but don't want the problem to come back and no one I know seems to know what to do in my scenario. I'm open to everything from galvanic isolators to auditioning for the boat version of "Pimp My Ride" should such a day come round.

I can make the bottom fair smooth, repaint and LOOK great. What I don't want is to have an unresolved problem re-eat my boat, $$$ and work put in, and especially don't want to sink. My prop shaft/prop, rudder shaft/rudder need to be replaced. I have a great unknown with that keel part (see pics!) from the previous owner. Please leave chastising re: surveyors at the door for this thread. I've since learned what I didn't know.

The lead keel part has the texture of the moon. I can re-epoxy everything, but I can't verify the integrity nor existence of any horizontal bolts holding it in. I see 6-7 visible keel bolts under the floor panels in the salon. Those are in decent shape, but how do I know if my metal eating issue has or has not hurt the supports holding this part on?
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Old 28-08-2014, 12:38   #2
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Re: Galvanic corrosion or Stray current? NEW PICS!!

Stray current and probably a good dose of neglect. And the stray current more than likely originated aboard your boat.
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Old 28-08-2014, 12:51   #3
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Re: Galvanic corrosion or Stray current? NEW PICS!!

Hey! Thanks for the fast reply!! I saw you in your "consider the diver alerted thread"!!

Seems that is the case, but is it such an invisible gremlin problem that can't be rooted out? I feel helpless boxing without arms. How does one find and resolve the issue that did this? Is there a device or service professional that can help me? I don't want to be the fool to rebuild a sandcastle that the ocean destroys again five minutes later. Thanks!!
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Old 28-08-2014, 12:55   #4
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Re: Galvanic corrosion or Stray current? NEW PICS!!

A marine electrician should be able to run down the issue without problem.
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Old 28-08-2014, 12:58   #5
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Re: Galvanic corrosion or Stray current? NEW PICS!!

I'd start with finding a good Marine electrician and beginning there if your not comfortable with doing it yourself. He will know to look for an isolation transformer and check your wiring etc.

What's the PVC female pipe fitting for?
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Old 28-08-2014, 13:37   #6
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Re: Galvanic corrosion or Stray current? NEW PICS!!

female pipe fitting... err, yes, my first haul out so hoping to discover what all the ins/outs are going to. I have two cockpit drains at the stern, and the water output for the engine, then I'm at a loss so far. I've already learned so much this year but still have a ways to go!
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Old 12-09-2014, 11:56   #7
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UPDATE! Re: Galvanic corrosion or Stray current? NEW PICS!!

Certified marine techs looked it over: my engine created a charge, so it did originate in the boat. The previous owner reversed some wiring on the panels too- all will soon be resolved. So the flowchart now seems to be - sandblast the lead part of the keel-> apply 3 coats of Interlux Interprotect HS-> fair the lead with epoxy. The keel bolts checked well and structurally the pros said that the lead portion isn't going anywhere and if the stray current issue is resolved, it won't get damaged by corrosion anymore.

NEW QUESTION: No one seems to have heard of/seen my keel situation before (please see pics in album for reference). Forgive my newbie understanding of keels: The Columbia 9.6, a fiberglass boat, had a fiberglass keel. Displacement/ballast weight comes from somewhere, so is it fiberglass over lead? The previous owner did that 90 degree angle lead replacement in the pics. I assume the boat ran aground and that was his fix, be it good or bad. So do I now have a partial fiberglass keel and partial lead or is the whole keel lead, but some in exposed and some not?

I ask because if all is faired over and painted, it should look good and be structurally strong. A suggested option is to glass over the exposed lead after the above flowchart's fairing which would make it even stronger structurally and would eliminate the stray current worries on the keel permanently. Is this a good idea?

It is a costly job with tradeoffs: I'd need to install a new lightning ground plate on the hull. Also another opinion offered AGAINST glassing over is that any damage to the glass and I can no longer SEE the damage to the lead getting eaten. He suggests this would NOT be a permanent stray current/electrolysis/galvanic solution - only a temp one as everyone runs aground at some point.

So in a nutshell, I'd love to know how you all would do your keel if it looked like mine. Thanks!
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Old 12-09-2014, 14:37   #8
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Update two - Good news!

I just found out that the keel that stumped the pros is actually INTENTIONALLY designed as pictured and it is not some odd repair after an accident/bad grounding!! I can't believe how hard it was to find info on this (THANKS WOODY!). It is a keel and "sump" and I'm looking at a "keel-to-sump joint." I don't understand the advantage of this setup vs had they just made the sump part a full keel extension of the lead.

So my lead portion may just be a normal lead keel with normal lead keel problems. Some suggest that the pitting is normal sea corrosion or at worst, SOME stray current damage. Seems now that sandblasting the lead, Interlux barrier coat (3x), fair with epoxy, primer and bottom paint (2x) and the keel is done!

Would the much smaller job of glass and/or epoxy to seal the space between the sump and keel be overkill?
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