To bond or not to bond

[Longo]

Hello and happy holidays to all -
I have an 85 Albin that at one point, possibly from the factory, all was bonded - motors, thru hulls, fuel tanks - basically all the metal in the bilge. It was done via a thin tinned copper strap that runs down both sides of the boat and all the parts are connected to this. At this point i would say about half of the connections have gone bad. What is happening is that i get a ridiculous amount of barnacles on the boat - like shag carpeting, and my anodes last about three months. But - after i did the whole strip the bottom/barrier coating thing my anodes were essentially untouched this past season. So - i have been told i have a “hot” boat and should check bonding. I have also been told to rip out all of the bonding and do not replace it - that is causes more harm than goon. I just read an entire sting on this within this forum, and again both pro-bonding and no-bonding views and articles are represented. As well, i have read both pro-bonding and anti-bonding articles through various publications on my own - bottom line is that i am thoroughly confused - should I replace /update the bonding including adding bonding brushes to my shafts being that they are dripless or do i rip all out?
Sorry for the long entry - just so confused at this point.

Thanks!!
John.

 

[Comodave]

Welcome aboard. There is some contention as to whether or not to bond. I prefer bonding so I am just finishing up redoing all the bonding in our boat. The bonding system was in poor condition when we bought the boat. Does your boat have a transom anode? Your anodes should last longer than 3 months. Personally I would reconnect all the underwater metals on the boat. Then have a certified marine electrician that is well versed in corrosion come and test your boat and see if you have adequate anodes or not. You may need more/larger anodes to properly protect your boat. Steve D’Antonio (spelling?) has some excellent articles on his website about this topic. Good luck.

 

[DavidM]

Some say bond, some say don't bond. There are good arguments on both sides. But if you already have bonding and it is in need of repair, I would repair it.

David

 

[Longo]

Thanks for the replies. I do have two large transom anodes that again saw no corrosion this past season. I will check out those articles by Steve D on this subject and will continue to research. Bottom line is that i will most likely repair all as mentioned.

One last question - is it necessary to use #8 green tinned copper or would your standard #8THHN wire do, which is what is in place now - that and #10 THHN...

And Litchfield - I’m over in Milford and keep the boat on the Housatonic.

 

[fgarriso]

The reason you have a "hot" boat is not due to the bonding. You have stray current leakage around your boat. That may be AC or DC, but somewhere you've current leakage in the boat. Do you have shore power connected to the boat when at the dock? If so are you sure you have proper grounds on the dock and in your boats AC system. I helped do a ground fault test at a newer large marina and found 50% of the pedestals had minor to major faults.

 

[OldDan1943]

Dont do anything until you get a certified marine electrician then let him (with your help) rebuild your system.
If your zincs last only 3 month, your bronze hull valves maybe deteriorate also.

 

[scurvydog_pnw]

You could also have a hot boat next to you in the marina as well. Get a certified marine electrician and they can test out the existing bonding system to make sure everything is setup correctly and also test each piece of equipment that it is properly bonded back to the central ground point.

You did not say whether you had an isolation transformer on the shore power or not? That can break the connection between you and possibly your neighbors boat sucking down all your anodes.

Cheers,
-R

 

[OldDan1943]

You could also have a hot boat next to you in the marina as well. Get a certified marine electrician and they can test out the existing bonding system to make sure everything is setup correctly and also test each piece of equipment that it is properly bonded back to the central ground point.

You did not say whether you had an isolation transformer on the shore power or not? That can break the connection between you and possibly your neighbors boat sucking down all your anodes.

Cheers,
-R

Bingo

 

[FF]

In the past bonding was required of boats that used a SSB radio , not many do today.

 

[boatpoker]

In the past bonding was required of boats that used a SSB radio , not many do today.

You seem to be referring to a ground plane, not the same thing.

 

[boatpoker]

Hello and happy holidays to all -
I have an 85 Albin that at one point, possibly from the factory, all was bonded - motors, thru hulls, fuel tanks - basically all the metal in the bilge. It was done via a thin tinned copper strap that runs down both sides of the boat and all the parts are connected to this. At this point i would say about half of the connections have gone bad. What is happening is that i get a ridiculous amount of barnacles on the boat - like shag carpeting, and my anodes last about three months. But - after i did the whole strip the bottom/barrier coating thing my anodes were essentially untouched this past season. So - i have been told i have a “hot” boat and should check bonding. I have also been told to rip out all of the bonding and do not replace it - that is causes more harm than goon. I just read an entire sting on this within this forum, and again both pro-bonding and no-bonding views and articles are represented. As well, i have read both pro-bonding and anti-bonding articles through various publications on my own - bottom line is that i am thoroughly confused - should I replace /update the bonding including adding bonding brushes to my shafts being that they are dripless or do i rip all out?
Sorry for the long entry - just so confused at this point.

Thanks!!
John.

Are you up river moored in fresh water ? If so what anode material are you using ?

 

[Longo]

Old day all,

Appreciate all the feedback.
I am up river so mostly fresh water - first year I had aluminum which just did not last, they were eaten up in no time. Replaced with Zinc on short haul and those were OK. This past season cannot remember, believe zinc, and they were untouched after the season so go figure.
Adjacent hot boat - there is a chance of that but am in a new marina this coming season so will be a good test.
Shore power tower issues - again, chance. Due to location our docks are taken out of water each year so the towers all get removed and stored - as you could imagine this leaves a lot of room for issues as the connections on both ends get removed and coiled in the docks for storage.
Professional marine electrician - rare breed in my area, hard enough in finding a marine mechanic who travels with formal credentials, will do some research.
Will take a close look at repairing what is in place and take a long look at all the wiring on the boat - something to do over the next few months while the boat is on the hard.

Again - appreciate all the input. Thank you and a very happy, safe, and blessed New Years to all.

 

[boatpoker]

Old day all,

Appreciate all the feedback.
I am up river so mostly fresh water - first year I had aluminum which just did not last, they were eaten up in no time. Replaced with Zinc on short haul and those were OK. This past season cannot remember, believe zinc, and they were untouched after the season so go figure..

The aluminum anodes are the correct material for your waters and they deplete because they are doing their job.

The zinc accomplishes nothing in fresh water and last because they are not working.

If you truly have a stray current issue (DC leak), other metals below the waterline will show symptoms that are easily recognised.

Look up the closest ABYC Certified Marine Corrosion tech here ... https://abycinc.org/page/CorrosionCert

 

[FF]

"You seem to be referring to a ground plane, not the same thing."

Actually all the underwater metal was tied into the ground plane , for a better "push".

 

[Redhook98]

So, all this is good advice. But take it one step further and go buy yourself a silver-silver chloride anode that you can connect to your multi-meter. You can check how your bonding system is doing whenever you wish, isolate and test parts and find faults on yours and others boats. I have used it to isolate a boat at our marina that was causing issues and figure out exactly how much anode material I needed for my setup. All this without paying big bucks for a marine electrician.



I figured this all out with my first Marinette about 20 years ago. Had a steel Roamer after that. I needed to learn these things.



BTW, the bonding system on my boat had been completely removed (1979 490ft MT). The copper strips on both sides of the keel are still there, but nothing else. After seeing that here was a 5-ohm difference between by transmissions and shafts, I went ahead and installed a new bonding system that only connected my shafts/props, struts and rudder gear. All of my underwater metal is either completely isolated with at least 100-ohms, or part of that bonding system. No electrical system is connected in any way to any external metal either. My silver-silver chloride anode has me at a perfect -.950v of protection with aluminum anodes and in brackish water. The anode of which I speak was instrumental is creating this.


Just my 2-cents.

 

[OldDan1943]

After installing my bonding system, I installed an additional grounding point on deck. If necessary I can install a zinc fish, if necessary.

 

[Hippocampus]

An equipoise isn’t a ground. In my last two boats they were glassed into the hull at time of initial layup so wouldn’t ground anything.

 

[Comodave]

I agree on the aluminum anode. The reason it was being eaten up was that it was doing it’s job. That is what it is supposed to do. The reason the zinc anode was lasting so long is because it isn’t working. It may last forever and your underwater metals are being eaten up instead of the anode. It is a false economic savings to use zinc because it lasts and then have to replace your through hulls, prop and shafts. You may need more anode surface area. So get a silver half cell and check the readings and see where your boat is.

 

[scurvydog_pnw]

A good sourcing if your working on ground issues is Boatowners Mechanical and Electrical Manual by Nigel Calder.

I had to troubleshoot a pump that was not grounded and you should have no more than 1 ohm resistance between any device and your central grounding point.

In the book it shows how to test your grounding system against the water your sitting in.

 

[bglad]

If the zincs were untouched you should probably double check they are still connected to your bonding system...

Old day all,

Appreciate all the feedback.
I am up river so mostly fresh water - first year I had aluminum which just did not last, they were eaten up in no time. Replaced with Zinc on short haul and those were OK. This past season cannot remember, believe zinc, and they were untouched after the season so go figure.
Adjacent hot boat - there is a chance of that but am in a new marina this coming season so will be a good test.
Shore power tower issues - again, chance. Due to location our docks are taken out of water each year so the towers all get removed and stored - as you could imagine this leaves a lot of room for issues as the connections on both ends get removed and coiled in the docks for storage.
Professional marine electrician - rare breed in my area, hard enough in finding a marine mechanic who travels with formal credentials, will do some research.
Will take a close look at repairing what is in place and take a long look at all the wiring on the boat - something to do over the next few months while the boat is on the hard.

Again - appreciate all the input. Thank you and a very happy, safe, and blessed New Years to all.

 

[Redhook98]

I knew (know) people who would take their old zincs and throw them into the water next to their boat, thinking this would help. Lol!

 

[Steve DAntonio]

The argument for bonding, vs. against, is far stronger for a number of reasons, including mitigation of stray current corrosion, it offers centralized cathodic protection, reduces the possibility of electrocution and it can help dissipate lightning strikes and related damage. All of these observations are based on both my first hand experience as well an ABYC Corrosion Certification.

I find that those who discourage bonding usually do so based on anecdotal rather than scientific evidence, i.e. "I had a boat that was bonded and had nothing but problems, cut all the bonding wires and things were fine after that, and my zincs lasted much longer" (an actual quote from a lecture attendee).

Perhaps the only application where bonding doesn't make sense is timber hulls, because bonding does create an alkaline solution around cathodically protected metals, which leads to delignification of the timber.

Remember, the threshold for resistance in bonding systems is very low, no more than 1 ohm between anode and protected metal, so the wiring must be in absolute tip top condition, clean, secure and corrosion inhibited.

More on bonding systems here https://stevedmarineconsulting.com/wp-content/uploads/2014/03/BondingSystems138_05.pdf

 

[Boatcrazy]

Following. We have had an issue with Stray Current Cr, blowing the anti-foul paint off several thru-hulls on our f/g hull. Turned out to be a marina issue, but testing is the only way to determine. Get the half-cell!

 

[Steve DAntonio]

Following. We have had an issue with Stray Current Cr, blowing the anti-foul paint off several thru-hulls on our f/g hull. Turned out to be a marina issue, but testing is the only way to determine. Get the half-cell!

Paint failure around bonded underwater hardware, in the absence of metal loss, is nearly always the result of over-protection (and it is not harmful to FRP vessels except to the paint). In the strict sense of the term, stray current almost always originates on the vessel suffering the damage (because its energy source is the vessel's batteries), not from a marina or other vessels.

It's possible for your vessel to be over-protected by another nearby vessel, if it is way over-zinced and neither vessel has a galvanic isolator. By the same token, your anodes can protect nearby vessels if you don't have a galvanic isolator. This is galvanic not stray current corrosion.

Marinas rarely cause corrosion because corrosion is almost always a DC phenomenon, and marinas don't use DC per se. If you are moored next to a large steel bulkhead, and you have no galvanic isolator, then your anodes will try to protect that steel, and be depleted very quickly, and then your underwater metals are susceptible to corrosion, so I suppose that could be considered a marina problem, but not really since a GI would prevent it from occurring.

More on the "hot marina" myth here. https://stevedmarineconsulting.com/unraveling-the-corrosion-mystery/

 

[backinblue]

Hello and happy holidays to all -
I have an 85 Albin that at one point, possibly from the factory, all was bonded - motors, thru hulls, fuel tanks - basically all the metal in the bilge. It was done via a thin tinned copper strap that runs down both sides of the boat and all the parts are connected to this. At this point i would say about half of the connections have gone bad. What is happening is that i get a ridiculous amount of barnacles on the boat - like shag carpeting, and my anodes last about three months. But - after i did the whole strip the bottom/barrier coating thing my anodes were essentially untouched this past season. So - i have been told i have a “hot” boat and should check bonding. I have also been told to rip out all of the bonding and do not replace it - that is causes more harm than goon. I just read an entire sting on this within this forum, and again both pro-bonding and no-bonding views and articles are represented. As well, i have read both pro-bonding and anti-bonding articles through various publications on my own - bottom line is that i am thoroughly confused - should I replace /update the bonding including adding bonding brushes to my shafts being that they are dripless or do i rip all out?
Sorry for the long entry - just so confused at this point.

Thanks!!
John.

Hi John,
I am on the Housatonic in Stratford and have a similar problem. My zincs wear away quickly and I get lots of barnacles. Everything in my boat is bonded. There is an article on West Marine that advises against bonding the through hulls. I can see how that makes sense in theory, but it's a shame that there is so much mystery on this subject rather than a set of rules that every boat should follow. I did a test on my boat with a reference anode and everything tested ok but when hauled in the fall, zincs were badly work an lots or barnacles on the underwater metals. Milford BoatWorks said they will look into it this spring. Who knows?

 

[Longo]

Backinblue - i was at the Valley YC - moving up to Rivers End next season to get away from the current...have seen your boat on the river - beautiful boat.

Redhook98 - "Everything on your boat is broken.... You just don't know it yet." - this is right up there with the quote “there are two types of boaters, those who have ran aground and those that are going run aground” - love it, thanks for the laugh! And will put this one in my boating quotes library!

Be well all!!

 

[backinblue]

Thanks Longo, see you on the water soon! Keep in touch on the bonding stuff. I'll let you know what MBW says.

 

[Longo]

Will do - thanks!