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02-12-2017, 04:51
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#16
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Registered User
Join Date: Sep 2015
Location: Milwaukee, WI
Boat: O'day 34, O'day 39
Posts: 62
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Re: Bonding, electrolysis questions
Quote:
Originally Posted by fstbttms
I believe the hull/keel joint issue is what we call "burnback" and it is due to improper priming of the underlying metal.
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That may be possible, but I had seven coats of Interprotect 2000e on the keel, and seem like that would explain the similar symptoms at the metal through hulls that are connected by the bonding wire which were also coated with Interprotect? Also seems odd that it would affect both sides of the keel in the location of the same keel bolt - the one with the bonding wire attached to it.
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02-12-2017, 05:01
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#17
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Registered User
Join Date: Sep 2015
Location: Milwaukee, WI
Boat: O'day 34, O'day 39
Posts: 62
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Re: Bonding, electrolysis questions
In the linked article, the author suggests decoupling the VHF antenna from the DC ground system by means of an inner/outer DC block. This is not a dime store piece of equipment and I am wondering why mounting the VHF whip on a non-conductive bracket wouldn't accomplish the same goal? The only issue I can see is that with the author's method the mast (and stays) are connected to the keel for lightning "protection", and the antenna whip would then be isolated from this system. Even if this means the DC grounding system is then vulnerable via the antenna whip, it seems that in practical experience this protection system is at best unreliable since most of the instruments in a strike are wiped out anyway?
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02-12-2017, 08:58
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#18
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Registered User
Join Date: Aug 2003
Boat: Dragonfly 1000 trimaran
Posts: 7,145
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Re: Bonding, electrolysis questions
As a boat is supposed to have only one common ground point, decoupling the VHF is exactly what I did.
Operation is unaffected.
__________________
The question is not, "Who will let me?"
The question is,"Who is going to stop me?"
Ayn Rand
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02-12-2017, 12:08
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#19
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Moderator
Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 21,156
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Re: Bonding, electrolysis questions
Question for BoatPoker or other knowledgeable person: why is a large conductor (ie 8 ga) required for bonding? Surely the currents involved are very small, so voltage drop would be infinitesimal, so I'm wondering. And why is an insulated conductor needed? And finally, if the "wrap and clamp" method is not good enough (and I can see that it is quite prone to corrosion in a damp bilge), what is the best means of connecting to a typical through hull and valve setup as seen on most production boats these days? No handy bolts there for a ring terminal...
Jim
__________________
Jim and Ann s/v Insatiable II, lying Port Cygnet Tasmania once again.
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02-12-2017, 13:26
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#20
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Marine Service Provider
Join Date: Nov 2008
Location: Port Credit, Ontario or Bahamas
Boat: Benford 38 Fantail Cruiser
Posts: 7,061
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Re: Bonding, electrolysis questions
Quote:
Originally Posted by Jim Cate
Question for BoatPoker or other knowledgeable person: why is a large conductor (ie 8 ga) required for bonding? Surely the currents involved are very small, so voltage drop would be infinitesimal, so I'm wondering. And why is an insulated conductor needed? And finally, if the "wrap and clamp" method is not good enough (and I can see that it is quite prone to corrosion in a damp bilge), what is the best means of connecting to a typical through hull and valve setup as seen on most production boats these days? No handy bolts there for a ring terminal...
Jim
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ABYC does not require an insulated conductor although that is an acceptable option.
The big issue is resistance. Given that many of these conductors may be in bilge water at some point (Corrosion) and distances between bond points may be significant and the very low voltages involved, the heavy conductor helps ensure the current will flow as required.
I'll be happy to respond with a copy of the Cathodic Protection Standard if you email me boatpoker@gmail.com
__________________
If you're not laughing, you're not doin' it right.
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03-12-2017, 09:33
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#21
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Commercial Member
Join Date: Dec 2008
Location: St. Petersburg, FL
Boat: Gulfstar Long Range Trawler; 53'; BearBoat
Posts: 1,525
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Re: Bonding, electrolysis questions
Boatpoker Post #20
You are correct about trying to minimize resistance in the bonding circuit. However; per the current ABYC E2 "Cathodic Protection":
Quote:
2.5.8.1Cathodic bonding conductors shall be oil resistant insulated, tinned,stranded copper wire, or uninsulated copper strip. Copper braidor copper tubingshall not be used for this purpose,
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__________________
Charlie Johnson
ABYC Master Technician
JTB Marine Corporation
"The Devil is in the details and so is salvation."
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03-12-2017, 10:03
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#22
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Marine Service Provider
Join Date: Nov 2008
Location: Port Credit, Ontario or Bahamas
Boat: Benford 38 Fantail Cruiser
Posts: 7,061
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Re: Bonding, electrolysis questions
Just as I said, insulated conductor is not required.
2.5.8.1Cathodic bonding conductors shall be oil resistant insulated, tinned,stranded copper wire, or uninsulated copper strip. Copper braid or copper tubingshall not be used for this purpose,
__________________
__________________
If you're not laughing, you're not doin' it right.
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03-12-2017, 11:23
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#23
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Registered User
Join Date: Mar 2007
Location: Santa Cruz
Boat: SAnta Cruz 27
Posts: 6,711
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Re: Bonding, electrolysis questions
and what's wrong with copper tubing??
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03-12-2017, 11:29
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#24
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Registered User
Join Date: Apr 2007
Location: Marina del Rey, California
Boat: President 43 Sportfish
Posts: 4,105
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Re: Bonding, electrolysis questions
Quote:
Originally Posted by donradcliffe
and what's wrong with copper tubing??
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ABYC forbids it.
__________________
1st rule of yachting: When a collision is unavoidable, aim for something cheap.
"whatever spare parts you bring, you'll never need"--goboatingnow
"Id rather drown than have computers take over my life."--d design
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03-12-2017, 11:40
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#25
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Registered User
Join Date: Mar 2007
Location: Santa Cruz
Boat: SAnta Cruz 27
Posts: 6,711
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Re: Bonding, electrolysis questions
given ABYC's track record, I have to ask why?
If copper strapping is OK, why not flattened copper tubing?
Why not unflattened copper tubing?
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03-12-2017, 13:24
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#26
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Senior Cruiser
Join Date: Sep 2014
Location: puget sound washington
Boat: 1968 Islander bahama 24 hull 182, 1963 columbia 29 defender. hull # 60
Posts: 12,121
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Re: Bonding, electrolysis questions
Quote:
Originally Posted by Terra Nova
ABYC forbids it.
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The ABYC can't require anything they can only recommended .
__________________
Non illigitamus carborundum
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03-12-2017, 13:26
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#27
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Senior Cruiser
Join Date: Sep 2014
Location: puget sound washington
Boat: 1968 Islander bahama 24 hull 182, 1963 columbia 29 defender. hull # 60
Posts: 12,121
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Re: Bonding, electrolysis questions
Quote:
Originally Posted by donradcliffe
given ABYC's track record, I have to ask why?
If copper strapping is OK, why not flattened copper tubing?
Why not unflattened copper tubing?
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Don you can actually do it with whatever you have or want to do it with.
There are no rules to follow for it .
The ABYC can only make recommendations.
__________________
Non illigitamus carborundum
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