To bond or not to bond?

[maxim_rfeld]

I am considering to “unbond” my boat, remove all bonding between seacocks, chain plates, etc. Any expireance with this project? Can you suggest any literature that describes this subject (except Calder)?

Max.

[Silmaril]

Interesting thought. What would your objectives be for the "un-bobnding" project? Is there something you are wishing to accomplish that bonding would interfere with? Worried about the horror stories of a lighning strike blowing bonded through hulls clean off the hull? Is the upkeep of your present bonding becoming too costly in respect to it''s stated benefits?

My boat is what you may call "partially bonded" in that some systems are bonded, while others are not. I have all of my electrical, my engine, prop shaft, mast, standing rigging, and steel hull matrix bonded. I also use a galvanic isolator in my shore power circuit.

Things that are not bonded in my boat are life lines, stanchons, seacocks, fuel tank (diesel), water tank, and hydraulics (Navtech backstay and vang). I don''t think it matters but I replaced my 27 year old bronze through hulls (which showed no signs of corrosion or brittleness) with marlon.

I found that once I completed the bonding of the first group of items, along with the galvanic isolator, I started to get better performance from all of my electronics (VHF, GPS, full NEXUS Wind/Speed/Depth/Data, stereo, charger) longer life on my zincs (the isolator is to blame for that) better battery performance as indicated by my LINK 20 Dual Bank Monitor, and less corrosion at the other bonded parts.

Of course, much of the increase in performance may be due to the complete PROPER rewiring of the entire boat at the same time. The previous owners had made a mess of things over the 24 or so years prior to my taking on the project.

In my opinion, there are definate advantages of some things being bonded, while others may be less appearant.

[maxim_rfeld]

You pretty much described it in the first paragraph: old corroded system, lightning protection is not adequate (I have a ketch and have to take care about grounding two masts!). Plus I already have isolated shaft (flexible coupling) that will help the “un-bonding” process. On another hand I have complication in the form of cooling plate for my Frigoboat fridge.

Max.

[dirtchickn]

Some folks in our marina recently had a catastorphoc failure of the rigging due to a chainplate that was damaged by a lightning strike a few years back. I''m not sue if it was bonded, (I am trying to find out) but the moral is the official cause of the failure was damage due to the lightning. If your system is already subpar, do you really want to risk bringing that much energy to other parts of the boat? If lightning has the potential to weaken a chainplate in such a way as to render it undetectable, I would not want to be energizing anything else through poor craftmanship.


By the way, the boat is owner by the most attentive of sailors. This failure was not due to his lack of inspecting the rig. I''m sure that if there had been any way to prevent the demasting, he would have done it.

[maxim_rfeld]

Than what you are saying is to unbond evrything, right? If so that was my line of thinking as well. I am planning to use external lightning conductors instead: http://www.strikeshield.com/Emain.html or somthing similar.

Max.

[GordMay]

The boat is sitting in conductive water - how do you expect to isolate (un-bond) it?
Imperfect isolation results in "partial bonding" - why not bond it properly?