Bonding,Zincs

[Saltyhog]

Originally Posted by casual

Thanks al I,am learing,My boat is Kept at MY home.I,usually have shore power connected,for battery maintence.This New to me Cabo Is a Learing curve after 22 years with my last boat Its a Big Curve'
Saltyhog you mention that the 2 zincs thru bolted P&S aft connect to the Rudder Shaft Log,&Tail piece,do the rest of your thru hull wires connect there also?When I,removed these, the wires were connected to the zincs laying loose on the other end.I.had no idea where they went.You Have helped me a lot Thank You and all others.

I think one of the zinc plates is to the rudder shaft and shaft-log/tailpiece. The other goes to the thru-hulls. I'll double check this weekend when I'm on the boat. It sounds like sombody may have been having problems with a hot marina and disconnected the bonding wires. That's not the approach I would take. Hope it helps.

[casual]

Thanks againg,Do all the bonding wires from the thru hulls link from thru hull to thru hull and then the last link continue to the zinc or does each thru hul have a seperate wire running to the zinc.Seems as though I,am finding shortl wires here and there in the bilge.I,also found 1 red wire connected to the zinc,probably ran out of black short piece ging nowhere.I,read some where that bonding should be to the engin.AmI,dreaming.Thanks

[epistosaurus]

Originally Posted by Vyndance

Put 2 dissimilar metals in an electrolyte solution and you have a battery. That is what is going on under your boat.
...
The boat needs to be bonded from the grounded and grounding conductor to everything that contacts the water to the plate zinc.

Two dissimilar metals in electrolyte is a battery, that is right. However it is still an open circuit so no electrolysis.

You bond and close the circuit. If the zinc is present and well connected and if the bonding is solid AND if we do not have stray currents, things work as intended and zinc is eaten. But without closing the circuit - ie no bonding of electrically separated metals - there is no galvanic corrosion at all so things work as well.

And with stray currents even zinc won't protect you if you are bonded.

Bonding makes sense where you cannot electrically isolate dissimilar metals from each other , say shaft and prop. Of course they are bonded already so all you need is zinc. Truth be told unbounded boats are harder to lightning- protect. But not impossible.

Rafal

[goboatingnow]

Originally Posted by epistosaurus

Two dissimilar metals in electrolyte is a battery, that is right. However it is still an open circuit so no electrolysis.

You bond and close the circuit. If the zinc is present and well connected and if the bonding is solid AND if we do not have stray currents, things work as intended and zinc is eaten. But without closing the circuit - ie no bonding of electrically separated metals - there is no galvanic corrosion at all so things work as well.

And with stray currents even zinc won't protect you if you are bonded.

Bonding makes sense where you cannot electrically isolate dissimilar metals from each other , say shaft and prop. Of course they are bonded already so all you need is zinc. Truth be told unbounded boats are harder to lightning- protect. But not impossible.

Rafal

Don't bond on GRP boats. There's absolutely no need.

Dave

[delmarrey]

If one is going to bond, then they should install a cathodic protection system. That is the best thing for marina dweller. >>> What is cathodic protection? Protect your boat or yacht from electrolysis in both fesh and salt water.

[Blue Stocking]

See what I meant about wars?
Interesting though, rbates says bond--and he has a Cape Dory.
They are one of the few builders who didn't bond, IIRC.
Jus sayin.

[goboatingnow]

Originally Posted by Blue Stocking

See what I meant about wars?
Interesting though, rbates says bond--and he has a Cape Dory.
They are one of the few builders who didn't bond, IIRC.
Jus sayin.

Virtually no European boats as built are bonded.

Dave

[sailorboy1]

Originally Posted by casual

Thanks againg,Do all the bonding wires from the thru hulls link from thru hull to thru hull and then the last link continue to the zinc or does each thru hul have a seperate wire running to the zinc.Seems as though I,am finding shortl wires here and there in the bilge.I,also found 1 red wire connected to the zinc,probably ran out of black short piece ging nowhere.I,read some where that bonding should be to the engin.AmI,dreaming.Thanks

I just don't under what the hull zinc is for and why you would bond your thoughs to it. That just sets up a dissimlar metal loop. But guess once the zinc is gone all the though hulls would be at the same potential, which is the only reason to do it.

My last boat had the though holes bonded. All that did was allow a current that took out one of them. If you bond the the connections have to be kept in good condition.

Personally I wouldn't bond. But since it was that way to start I understand why you believe you should redo the same way. But would the different color wires etc I would say some owner did this not the builder.

IF you decide to bond the though fittings DON'T connect the loop to anything else, including the engine. You aren't trying to make a ground circuit just to keep all the fittings at the same potential so they don't have a circuit. The though fittings should only be connected to each other.

[fstbttms]

Originally Posted by funjohnson

Here is Westmarine's article about bonding (click here)

In an increasing number of marinas, there are substantial DC electric currents running through the water.

Boy, I'd like to see the data backing this little gem up.

[casual]

I,have lived with sailboats for 35 years without bonding,why did I,have to buy one that was,even got struck by lighting once not bonded,no damage other than electronics and a transmission bearing,If I,skip all the bonds and just bond the shaft lod and rudder which has been reccomend am I,helping or hurting.
Thanks

[Cheechako]

Some say bonding completes the circuit creating the issue. Some say not. If you boat had no issues why not do exactly what it had before?

[Celestialsailor]

Originally Posted by delmarrey

The problem arises when one has different metals in contact with each other under water. e.g. bronze prop/SS prop shaft. This is why shaft zinks are so important.

This is my way of doing it also. Bronze by itself,...ok. Bronze prop on SS shaft...zinc it. Now...If you're in a hot harbor...the math changes. But it's a better idea to see who has that Sears, $12. battery charger. Usually the boat down a few with the blue tarps on it.

[delmarrey]

Here's some more good info>>>> Bonding and Corrosion

[epistosaurus]

Originally Posted by delmarrey

Here's some more good info>>>> Bonding and Corrosion

This indeed very well written - thanks.

Calder says more-less the same thing, but I can sense he is a bit more pro-bonding. If one leaves lightning protection out of it (some advocate grounding your thruhulls to the mast to eliminate a possibility of side-bolts when thunder hits, which could blow your thruhull, but I think this may be a bit of an overkill) then there is no reason to bond thruhulls. But engine, mast and keel are a bit more complicated. Engine is DC- -negative in any case. It would be best to electrically isolate it from the shaft and prop, which is not that hard. Then there is a mast and keel (if not encapsulated). These are most complicated. I think WestMarine piece had it well described.

rafal