Fairey Earth !

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PeterCharleston
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Fairey Earth !

Post by PeterCharleston »

Hi
Toying with the idea of a copper or Aluminium bus-bar to run the Length of Charleston, if we can keep the progress and cash going, she will be Engined at Christmas/Winter and popped into the water next Spring/summer.
Initially it will only be shafts, rudders and P Brackets (do we really need trim Tabs ?) that will need Anode connection/protection.
Unfortunately there will be no interior, but to make provision for all the future metallic goodies, something we can tap into seems like a good idea? or am i being a tad daft ?

martinh
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Post by martinh »

I have read somewhere that all items that enjoy cathodic protection need to be individually wired to the sacrificial anode. I'm sure that the answer is here with supporting information https://mgduff.co.uk

Phil62
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Post by Phil62 »

When I put my Swordsman in the water in 2015 after the refit etc, it was also done before she was quite finished.
One of the things I hadn't checked was the earth bonding on all the skin fittings etc (it was poor), there was also a lot of old wiring re-used to get the boat in the water for the end of the season.

Initially I had a slight leak around one of the rudder tubes, so I used her for a couple of months then had her lifted for the winter.

It was a good job I did as my shiny new props were already starting to show early signs all was not well.

During that winter all the old wiring was removed and the boat totally re-wired, including re-bonding all the bronze fittings to the engine earth and one of the transom anodes (sealed and dipped all crimped ends).

As I am plugged into the shore supply I also fitted a galvanic isolator to the 240v system.

The leak around the rudder tube was due to bodged repairs over the years which had allowed water in, and caused the Agba to become de-lignified around the tube (this was also exacerbated by electrolytic action due to the poor bonding).

This area of the hull was then re-laminated in exactly the same way you are doing yours. Once the tube was re-installed to the dry timber and the wiring sorted, all the electrolytic action issues disappeared.

The guy using models in the videos below is well worth a watch.

I also managed to buy one of the silver Chloride reference electrode kits on ebay so I check every now and then that all is well.



https://www.youtube.com/channel/UC6M0sR ... JA0ySKVZpg

https://www.youtube.com/watch?v=vGehTCw_voI

https://www.youtube.com/watch?v=TV6SvBQShgA

I don't think you need to run a full bus-bar through the boat, but I would personally ensure everything is bonded to each other, including the engine blocks or neg terminal and also an anode. (I did however run heavy-ish lengths of tinned cable both forward and aft from the engine blocks to the various fittings and used one of the transom anode bolts as a distribution point in the aft cabin).

I used heat shrink and the stuff below to seal the crimped ends.

https://www.gaelforcemarine.co.uk/en/GB ... gIskvD_BwE

There are a lot of differing opinions on this, but that's what worked for me.



I have trim tabs fitted and they definitely make a difference, I'd bite the bullet whilst you're at this stage.


PS if you do run a bus-bar don't use Ally, it'll just turn to white dust.

PPS I also fitted shaft brushes.



Good Luck
Phil.

Ben
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Post by Ben »

Excellent reply by Phil. Silver chloride elctrode! My hero!

I've an admission to make, one summer I launched Playtime, there was a list of jobs to do as long as your arm, I was 6 weeks late connecting the bonding and it cost me a prop nut! Fizzed away to half its size.

My take on skin fittings is that if there is a bronze skin fitting, valve and hose tail, or the same in DZR, then no need to bond as there is no dissimilar metal, so nothing less noble than another to suffer. I have seen such a skin fitting with a stainless hose clip clamping a bonding wire to it, which to my mind is a backwards move as its introducing a dissimilar metal.

Anything where there is dissimilar metal, needs bonding, min 6mmsq tinned wire, ideally the tinned copper tube terminals crimped and soldered on. All back to the anode, check with a DVM for max 0.3 ohms. P bracket, rudder post, engine/box/shaft all should be bonded.

Galvanic isolator a good idea if connecting to shore power.

Agree with Phil, no aluminium!

Be interested to hear Rob Bingham's view.


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