Earth bonding survey comment

[MikeBz]

So… is there any point is any electrical bonding on a boat? Our 1993 GRP boat has single large hull anode with seacocks, engine block, propshaft etc bonded to it. There is no prop anode. This all looks original.

 

[vyv_cox]

The problem is that there is NO ACTUAL professional official examination / qualification to be a Surveyor. This - believe it or not - applies in the real shipping world as well. In the real shipping world - there are only a few specific items that call for Professional Qualifications ... Loadline ... Paint are two examples.

Yacht Survey outfits at best only have In-House guidelines ... I don't care what Mr XXXXX may have said about his 'membership' of any group - the fact is - it is unofficial In-House.

I know yards that have banned Surveyors from YBDSA and a few other groups ...

As a failure diagnosis specialist, some years ago I was invited to become a member of a new organisation, called from memory, Institute of Failure Diagnostics, entitled to letters after my name, M.I.F.D.E. or something similar. I looked at the membership requirements. If I attended two meetings and the annual dinner I could become a member!

 

[vyv_cox]

So… is there any point is any electrical bonding on a boat? Our 1993 GRP boat has single large hull anode with seacocks, engine block, propshaft etc bonded to it. There is no prop anode. This all looks original.

Very little. Modern thinking is that seacocks are made from corrosion resistant materials and can look after themselves. An engine cannot be protected by an external anode. Where the possibility of galvanic corrosion exists, e.g. a bronze/brass propeller on a stainless steel shaft, an anode should be fitted. A shaft anode, maybe with a prop anode also, will normally take care of this and satisfies the requirements: close proximity, direct contact, etc.

 

[Refueler]

As a failure diagnosis specialist, some years ago I was invited to become a member of a new organisation, called from memory, Institute of Failure Diagnostics, entitled to letters after my name, M.I.F.D.E. or something similar. I looked at the membership requirements. If I attended two meetings and the annual dinner I could become a member!

You will notice these 'organisations' are very careful about how they are classed .... Association is the most usual - as it has no formal or official req't for Qualification .. but using a term such as Association - gives illusion of such.

 

[dombuckley]

If you may permit me to apply a machete to this intellectual thicket...

The passage in the OP has nothing to do with anodes / cathodic protection.

What appears to have happened is that the surveyor has conflated bonding / earthing of electrical systems with bonding / earthing for mitigating the effects of lightning strikes (hence the bonding of metal parts above the waterline to those below). Most likely, the result of reading Nigel Calder's "Mechanical and Electrical Manual", where the two subjects are lumped together in the same section. It's a worthy tome, but it was written 35 years ago and aimed principally at the US market (hence the emphasis on lightning strikes and large AC electrical systems): there are a lot of things (such as the cathodic bonding of seacocks) which go against current custom and practice on this side of the pond.

However, these are both considerations for the design / installation stage, and are well beyond the scope of a normal survey: the passage, even if it was applicable (and much better explained), cannot be expected to be acted upon, unless the vessel is in build or undergoing a significant rebuild / refit.

In this situation, the passage in the OP is worse than padding: it just confuses the reader. It reveals shortcomings, either in knowledge or articulation, which undermine the rest of the report. In no way does it inform any decision to purchase the vessel concerned, and should not have been part of the report.

 

[Boathook]

When I have surveys done I Iike to be there to be able to understand their report better or to advise them on errors .......
I'm presently looking for a new to me boat and the insurers have said that the surveyor must be a member of some association or other. Luckily surveyors seem to be members of one or more of associations.

 

[Tranona]

If you may permit me to apply a machete to this intellectual thicket...

The passage in the OP has nothing to do with anodes / cathodic protection.

What appears to have happened is that the surveyor has conflated bonding / earthing of electrical systems with bonding / earthing for mitigating the effects of lightning strikes (hence the bonding of metal parts above the waterline to those below). Most likely, the result of reading Nigel Calder's "Mechanical and Electrical Manual", where the two subjects are lumped together in the same section. It's a worthy tome, but it was written 35 years ago and aimed principally at the US market (hence the emphasis on lightning strikes and large AC electrical systems): there are a lot of things (such as the cathodic bonding of seacocks) which go against current custom and practice on this side of the pond.

However, these are both considerations for the design / installation stage, and are well beyond the scope of a normal survey: the passage, even if it was applicable (and much better explained), cannot be expected to be acted upon, unless the vessel is in build or undergoing a significant rebuild / refit.

In this situation, the passage in the OP is worse than padding: it just confuses the reader. It reveals shortcomings, either in knowledge or articulation, which undermine the rest of the report. In no way does it inform any decision to purchase the vessel concerned, and should not have been part of the report.

Hence the typical reaction - it is complete nonsense and does not give one any confidence in the writer's competence as a "professional" expert on boats.