bonding thru hulls?

[kra]

I have H-28 that I just started restoring
currently all thru hulls (bronze) are bonded with heavy stranded copper wire and also all chainplates (stainless) to engine block (cast iron) and keel bolt (lead keel)
I have heard or read somewhere that wooden boats can have damage to planking around thru hulls bonded this way.
what is the best way to handle bonding/grounding of metal parts and engine? leave as is?
Is there a better approach ?
Thanks,
kra

[mmd]

Kra, at risk of sounding curt (sorry if so), this topic has been flogged pretty well hereabouts. Use the little search thingy in the upper right of the screen and have a look in the archives. If ya find something salient, post a reply to that topic & it'll come back up to the top so's we can all brush up on what we said back then. smile.gif If after you've read the previous posts you have something new to add to the pile, or a detail you'd like to thrash out, fire away, sir! :D

[imported_Conrad]

Arg- not on my boat, nope, never again!! :mad:

[kra]

ok
i will do the search thing first
thanks there really is a wealth of info in the
past posts
i appreciate replies and help
kra

[kialoa]

kra
In theory it works but in practice it doesn't,cut the fittings loose.
Rich

[Concordia..41]

If you can find it (and to save reading 20 threads), a great discussion on the history behind bonding and why not to do it was had just a few months ago when Donn W's boat Loon was hauled.

Regards -

[Allen Foote]

In case you can't find it....The bonding protects the metal but sacrifices the wood celuloise fibers. The bonding wires set up a minute electrical circuit. That circuit will break down water molecules. OVER A PERIOD OF YEARS....sometimes 20 to 30 years. The oxygen will turn the bronze green and the hydrogen becomes a hydrogen based acid that breaks down the celuloise fibers. Generally damage is concentrated in the bilge at frame hood ends. Check your fastenings....if they are sound around the thru-hull but are lacking threads 2-3 feet away from the thru-hull, then pull a garboard plank to inspect frame ends. Sometimes the timbers are effected and the damage is readily evident...such as the wood has been reduced to a white powder around bronze bolts (Strutts and rudder fittings) and the wood itself is missing from around the bolts. Use a grounding plate for the engine electricals and remove the bonding from the thr-hulls. You maybe sacrificing the thru-hulls in 10 years....but they are easier to replace -vs- reframing.

[ 01-01-2003, 03:38 PM: Message edited by: Allen Foote ]

[Donn]

Here's the thread: Bonding vs No Bonding (http://media5.hypernet.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=005408)

There's alot more as well, but I think the search thingy is hung over. I searched building and repair under my member #, and only got posts for the last 2 days.

[kra]

thank you all for advise and direction to further reading(wich i have done)
i think i will change a few things for sure and eliminate several zink anodes in the process
happy new year to all
Randy