Re: Maramu bonding question

James Alton


Viewed from the engine room, on my Maramu there is a copper strip that starts at the forward engine room bulkhead that runs aft down the inside of the Port engine stringer and then athwartships across to the stb. engine stringer running on the partial bulkhead forming the aft end of the grey water sump/bilge. My bonding strap was originally connected to the strip running athwartships on the sub. side. I moved the bonding strap connection to the inside of the Port engine stringer so as to orient the heavier copper plate so that it ran along the side of the hull which prevents blocking the drainage coming into the bilge from aft but functionally this works the same at the original setup. I have not extensively inventoried all items attached to the bonding system but the engine block, thruhulls, rudder, stuffing box, pretty much all of the underwater metals. The idea of bonding is to connect all of these metal bits to a sacrificial zinc that is less noble than the rest of the connected metals to protect the connected metals. One thing to keep in mind is that in a bonded boat, it is especially important to insure that your sacrificial anodes are always in good shape since each connected component will have a different position on the galvanic scale the the least noble pc. is going to corrode faster than if it was not connected to any other metals.

SV Sueno
Maramu #220

On Nov 17, 2019, at 5:37 PM, smiles bernard via Groups.Io <smilesbernard@...> wrote:

Hello Amelians

I’m going to attempt to redo my bilge bonding strap connection as part of this winters growing list
Thanks to this forum for excellent tips and tricks on this project so far.

In terms of the wider problem though. . .

On my boat I can’t really tell where/how the bonding cable used to run aft from the engine room to a rudder / anode connectio

so a few questions that would be amazing for this groups insight on:

What items are bonded ?
I assume: keel bolt and rudder are originally bonded. Would be grateful to hear if other items were also originally bonded. Through hulls for example ?

Also I’m a bit confused about the original cable run. Bonding vs. The Grounding plate for ssb

Be great to know how your bonding cables run from the engine room / keel bolt, aft to the rudder aft.

On the transom there is a copper strip /plate that runs down from the aft interior transom locker. I presume this is to do with the ssb ground not bonding ?

Many thanks in advance

Maramu 162

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