Bonding a Hunter 410

[2discover]

Hi all
None of the thru hulls on My Hunter 410 were bonded. It only has a zinc on the propeller shaft. Now I have replaced all the thru hulls and asked may self whether I shoud now bond the new bronze thru hulls. Any one has done this already? Is it required / recommended at all?
All thoughts are welcome
Marco

 

[Don S/V ILLusion]

[FONT=Arial, Helvetica, sans-serif]No, no, no ,no.[/FONT]
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[FONT=Arial, Helvetica, sans-serif]From the WM Advisor originally published in Practical Sailor[/FONT]
[FONT=Arial, Helvetica, sans-serif]Do not bond any thru-hulls or other immersed metal that can be electrically isolated. Specifically, keep your metal keel/ballast, your metal rudder shaft, your engine/prop, and all thru-hulls electrically isolated, from each other, and from the engine. [/FONT]
[FONT=Arial, Helvetica, sans-serif]It's worth understanding the reason. In an increasing number of marinas, there are substantial DC electric currents running through the water. If your bits of immersed metal are bonded, the electric current will take the lower resistance path offered by your boat in preference to the water near your boat, and the current will flow into one of your bits of metal, through your bonding wires, and then out another bit of metal. The anodic bit of metal or thru-hull that has the misfortune to be on the "out current" side of the current running through your bonding system will also become "out metal" and will disappear, sometimes rapidly.[/FONT]


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[Stu Jackson]

Don's right.

What made you think you needed or wanted to?

 

[2discover]

Stu,
I have two macerator pumps, discharging from the pump to a hose and the thru hull. Both of these thru hulls were badly corroded. I thought that there probably is some waste water remaing in the hose, allowing an electrical flow via the macerator pump. Therefore I thought that bonding these thru hulls could prevent the new thru hulls from being eaten away.

 

[Charles Erwin]

Try this. http://www.kastenmarine.com/_pdf/mbqCref.pdf

Both sides of the bonding argument are discussed at pages 7-10.

If you have the room put a bronze tee at each of your new through hulls and install a pencil zinc and plug in the odd leg. This will protect these through hulls from galvanic activity and eliminate hypothetical threats that can arise in traditional bonding circuits.

Charles

 

[Sailgunner]

I get some corrosion but don't think it has anything to do with bonding. BTW, took a lightening strike last April outside Miami and only electronics damaged, no hull damage.

 

[2discover]

Just to make sure that I got it right:
Do you consider a discharge hose from a macerator as electricaly isolated? Even when the ball valve is open and water verry likely goes all the way up from the thru-hull to the macerator.