Replacing Seacocks tomorrow...

[Groot T]

Thanks jfm, indeed not getting involved in the bond or not to bond discussion again..

Well, some people just don't like bondage. But then again, this will also raise the whole "what is a Fein vibrasaw with an offset diamond coated cutting head" issue..

Good work on the install, FireFly. Are you using Danboline in the engine room?

 

[DAKA]

I disagree 1000% with Daka on seacock bonding but we did that to death ages ago so let's not recount all the arguments here. All my seacocks are bonded to the anodes and I wouldn't have it any other way (it was Fairline standard spec in any case). I'm not aware of any serious boatbuilders who don't do this as standard spec (but would be interested to hear if there are any)

Well I disagree 10 000 %

We must be talking at crossed purposes, any chance you have a link to the thread please ?

All I can recall was Nick's 2 year old Princess having a problem with one seacock that he caught in time,
it had been inadvertently wired with a reinforced hose.
All other seacocks were fine.

Do you have a dedicated hull anode for the skin fittings , otherwise you are connecting the whole lot together , what am I missing .

I thought over 80% of boats were not bonded ?

http://www.ybw.com/forums/showthread.php?380218-Skin-fittings-Bonded-Not-Bonded

 

[jfm]

Well I disagree 10 000 %

I'm very happy to agree to disagree, to any percentage . I don't remember the thread well enough so cannot search for it, but we had a very thorough debate and there were opposing views. In my view none of the "no-bonders" made any convincing arguments for not bonding, so I stick to my "must bond" position. (Do you remember for example the argument that the ball is electrically isolated from the valve body by the PTFE sealing ring? Total nonsense that one). But they perhaps thought the same about the arguments in favour of bonding, haha! No matter - we definitely did it to death, and disagreed

 

[DAKA]

Will you at least agree any wire reinforced hoses should be checked the cut is clean
(check either end, its doesnt matter which) with the wire bent up so it cannot cut through the hose to cause a contact .

 

[MapisM]

any chance you have a link to the thread please ?

http://www.ybw.com/forums/showthread.php?283810

 

[DAKA]

Thanks Mapis :encouragement:

I made a small contribution to it too, nothing then or now changes my mind.

In my opinion (which appears consistent with the MCA report linked in the thread)

Modern boats with quality shafts,props and underwater fittings should not be bonded to seacocks/engines.

This may not be best advice for Old boats (eg, 1960 boat with steel shafts)
with steel or cheap stainless steel shafts with brass or cheap bronze props .

 

[MapisM]

This may not be best advice for Old boats

Well, fwiw the 15yo unbonded seacocks on my boat which I mentioned in that thread became 17yo in the meantime, and the boat is still afloat.
Touch wood, fingers crossed, etc. etc.

 

[burgundyben]

James- if you get down to the boat and are stuck for tools, hammers, crowbars, grinders, sockets up to 50mm, anything, call me, I have it all at home not more than a mile from your boat. I'm usually about on the weekends.

 

[Firefly625]

James- if you get down to the boat and are stuck for tools, hammers, crowbars, grinders, sockets up to 50mm, anything, call me, I have it all at home not more than a mile from your boat. I'm usually about on the weekends.

I really appreciate that Ben, thanks

 

[jfm]

Well, fwiw the 15yo unbonded seacocks on my boat which I mentioned in that thread became 17yo in the meantime, and the boat is still afloat.
Touch wood, fingers crossed, etc. etc.

MM, It's a total guess, but your s/cocks might have 2 different metals for the body and the ball, and these are electrically connected as the shaft passes thru the valve body. If so, that is a galvanic cell, in principle at least, as I know you will agree. Now it may be that the difference in nobility of your two metals is so small that the "fizzing away" of the less noble one is insignificant even @17 years, which is great news, and means they do not need to be bonded, But I don't think you can say (unless you have some info about it?) that is universally true of all seacocks generally on the market (not that you were saying that, I appreciate). It would be nice if the manufacturers actually did provide this data, but they don't, and so rather than leave it to fortune (which has favoured you and your boat ) I prefer to bond them which kinda takes away the uncertainty about the relative nobility of the two metals. That is kinda my thinking on this in a nutshell

 

[DAKA]

Well, fwiw the 15yo unbonded seacocks on my boat which I mentioned in that thread became 17yo in the meantime, and the boat is still afloat.

Hi Mapis,
I will alter my post , when I said old boat I was thinking pre 1970 .

15 years is modern

I'm just looking for a chart for jfm which shows the properties of his bronze props are the same as his Temet shafts.
Different metals but identical electrical properties (closer that a nats cock) so there isnt a risk of electrolysis.
His sole concern appears to be differing metals within the seacock
but if the different metals have the same electrical properties then they do not create an electrical current,
however if you connect them to the engine block and the engine pencil anode then you create an electrical current which you dont need. .

 

[Firefly625]

... Are you using Danboline in the engine room?

Indeed I am. The formulation has changed over the years, used to be thicker, but I still think its good stuff. As always, good prep is the answer and for me that meant, vacuming area, "washing" all surfaces to be painted with Wurth brake cleaner (always have on board) , sanding, vacuuming up dust, wiping down with a damp cloth, apply paint..

 

[MapisM]

(unless you have some info about it?)

Nope, I don't. And TBH, I also wasn't so interested in revamping the old discussion, at the end of which IIRC we agreed (sort of) that both alternatives have their pros and cons.
'Course the fact that my boat is getting close to the legal age for buying alcohol with her original seacocks still working doesn't prove anything...
...I just hope she doesn't take up drinking!

 

[MapisM]

Hi Mapis,
I will alter my post , when I said old boat I was thinking pre 1970 .

15 years is modern

LOL, no worries, neither myself nor my boat are feeling guilty or concerned for growing older.
Surely beats the alternative, anyway.

 

[jfm]

if the different metals have the same electrical properties then they do not create an electrical current,

1000% agreed Daka! As stated in my post replying to MM above. The thing is, I cannot get any info that tells me that the two metals in my or your or anyone else's seacocks have the same nobility, so I bond them because it renders the question moot. The SAFE answer, to give to anyone who doesn't know for sure the the two metals have ~equal nobility, is to bond them. But yes, if you KNOW the two metals have same nobility, then sure they do not need to be bonded.

 

[DAKA]

now its an easy project


We have established that brass doesnt mix with steel

Its a lot closer to stainless.

we have established bronze is substantially closer .

Thats two chunks off either end of the gap that we know for a fact without any checking .

Now we just need VicS to produce his table to show the two worst case examples

worst Bronze
worst SS

A small gap doesnt cause a big problem.

We are arguing about over protecting against a known very small gap
and purposely connecting to a known huge gap between the Bronze seacock and parts of an engine
that seacock bonding creates.

 

[jfm]

I have just removed mine and will replace at weekend, can't re-use handles as they were gate valves, I agree about the pads and would only use if was concerned about hull thickness, I have them now but don't think I need them. Biggest problem is no most seacocks are not far from a stringer and its important to make sure the inner and outer surfaces are parallel, should be ok when replacing but when fitting new will need checking, I have made up a tool for this using a grinding disc with the hole cut out to locate in the hole and fits into an electric drill. It's surprising how much you can take off to get level.

Do Fairline fit bonding wires in factory? every surveyor I have spoken to has allways advised against bonding.

Yup, all agreed. Fairline use a tool in facory to grind inner surface parallel, just as you describe
Yes, Fairline fit bonding in factory. TBH, just because a surveyor says something, it doesn't make it right. I'd want to hear the reasoning. Some surveyors understand physics/engineering properly and are sought out, and some don't which is why they are in a job with low barriers to entry

 

[jfm]

and purposely connecting to a known huge gap between the Bronze seacock and parts of an engine
that seacock bonding creates.

I don't agree that part of your analysis but agree the rest!

 

[burgundyben]

Yup, all agreed. Fairline use a tool in facory to grind inner surface parallel, just as you describe
Yes, Fairline fit bonding in factory. TBH, just because a surveyor says something, it doesn't make it right. I'd want to hear the reasoning. Some surveyors understand physics/engineering properly and are sought out, and some don't which is why they are in a job with low barriers to entry

Never ceases to amaze me that we keep talking about these things.

I suspect with bonding on new builds there might be as bit of marketing in the mix too, as in 'built with the best possible high quality fittings and all expertly bonded to the anode"

Istn't titanium the answer?

 

[rafiki_]

Never ceases to amaze me that we keep talking about these things.

I suspect with bonding on new builds there might be as bit of marketing in the mix too, as in 'built with the best possible high quality fittings and all expertly bonded to the anode"

Istn't titanium the answer?

Actually I would have thought the plastic route is best to avoid corrosion issues, and Vas has gone down this route. I would certainly consider it when I come to replace Rafiki's.