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Old 05-05-2017, 12:00   #31
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Re: Electrical Leakage Checks On The Hard?

Quote:
Originally Posted by zstine View Post
Are there any electrical checks I can do on the hard
Yes, there are. You can check resistances across your system (with a good multimeter - with long probe leads).

First check that your keel and thru hulls are actually unconnected to the DC systems (negative and positive) - normally one would check AC also but sounds like you dont use it much. You want a complete open circuit. Sometimes there are 'hidden' connections, and sometimes there is enough salt and other conductive 'dirt' to make a connection. If you find anything other than a complete open circuit here - track it down, clean it up. (this all can take some time if you have a bunch of wires).

Second, check the resistance between the items that are bonded and electrical system - should be very low to negative battery post.

Third, check the resistance across all your active connections. Start from the battery terminals one probe on the negative (check from the positive side after done with the negative) and move your other probe out along each circuit and check resistance after every connection (or as frequently as you can). There are benchmarks for how much resistance to expect per meter of wire and per each crimped or soldered connection . . . but really just look to keep the numbers low and if you see a significant jump up you know you have a connection (or whole wire) that needs to be cleaned up.

It would not be usual to find several connections that need redoing, and in an older boat - entire wire runs that need replacing.

The bottom line is: if your system is designed/wired as per the stan honey article* linked above in thread, and your connections are clean and low resistance, and 'unbonded' stuff is actually unconnected . . . then you have done about as much as you can.

There are benchmarks for how much zinc you should have on the outside of your hull. I am presuming you have an iron keel, and there are standards for zinc (both weight and spread I believe) per surface area. Id have to google up the tables and you can do as easily as I could. But for my aluminum hull (which was floating/unbonded) I had a dutch standard for this - the french used a different much lower amount of zinc - leading one to believe that these 'standards were up for some amount of debate.

* note: there are some detail different between abyc and stan honey and Nigel Calder - I have talked with all three, and they make some slightly different trade-offs. That is they all three have sounds reasons for their way of doing things. Personally I follow Stan, as by far the most intelligent and thoughtful and 'engineering experienced' of the three 'schools'.
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Old 06-05-2017, 08:52   #32
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Re: Electrical Leakage Checks On The Hard?

Quote:
Originally Posted by estarzinger View Post
Yes, there are. You can check resistances across your system (with a good multimeter - with long probe leads).

First check that your keel and thru hulls are actually unconnected to the DC systems (negative and positive) - normally one would check AC also but sounds like you dont use it much. You want a complete open circuit. Sometimes there are 'hidden' connections, and sometimes there is enough salt and other conductive 'dirt' to make a connection. If you find anything other than a complete open circuit here - track it down, clean it up. (this all can take some time if you have a bunch of wires).

Second, check the resistance between the items that are bonded and electrical system - should be very low to negative battery post.

Third, check the resistance across all your active connections. Start from the battery terminals one probe on the negative (check from the positive side after done with the negative) and move your other probe out along each circuit and check resistance after every connection (or as frequently as you can). There are benchmarks for how much resistance to expect per meter of wire and per each crimped or soldered connection . . . but really just look to keep the numbers low and if you see a significant jump up you know you have a connection (or whole wire) that needs to be cleaned up.

It would not be usual to find several connections that need redoing, and in an older boat - entire wire runs that need replacing.

The bottom line is: if your system is designed/wired as per the stan honey article* linked above in thread, and your connections are clean and low resistance, and 'unbonded' stuff is actually unconnected . . . then you have done about as much as you can.

There are benchmarks for how much zinc you should have on the outside of your hull. I am presuming you have an iron keel, and there are standards for zinc (both weight and spread I believe) per surface area. Id have to google up the tables and you can do as easily as I could. But for my aluminum hull (which was floating/unbonded) I had a dutch standard for this - the french used a different much lower amount of zinc - leading one to believe that these 'standards were up for some amount of debate.

* note: there are some detail different between abyc and stan honey and Nigel Calder - I have talked with all three, and they make some slightly different trade-offs. That is they all three have sounds reasons for their way of doing things. Personally I follow Stan, as by far the most intelligent and thoughtful and 'engineering experienced' of the three 'schools'.
We checked out boats for proper bonding or non-bonding on the hard many times using the process as described above. If not a a consistent either/or then it can cause zinc problems and other electrolysis (including hull damage). It doesn't check necessarily for electrical leakage you might have in the water but it might turn up a suspect for a path. Agree strongly with the rest of your comments.
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Old 06-05-2017, 09:23   #33
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Re: Electrical Leakage Checks On The Hard?

What kind of boat? What is the keel made of?

I've worked on a number of boats with external lead keels that have a seemingly reactive alloy that defies most attempts to keep the paint on. Usually the solution it's to separate the underwater metals so that the lead it's not commonly bonded with the engine & anything else "not lead".

Your best bet to figuring things out is actually when the boat is in the water. You need a silver-silver half cell and a meter to check hull potential and the flow of low level dc currents. I'd actually recommend you find a competent corrosion surveyor unless you have familiarity with the techniques involved.
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Old 06-05-2017, 09:26   #34
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Re: Electrical Leakage Checks On The Hard?

One other thought: when you de-bonded the keel, did you make sure the vhf antenna on the mast is not grounding out (through the braid and bracket) back to the keel via the lightning ground?
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Old 06-05-2017, 13:20   #35
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Re: Electrical Leakage Checks On The Hard?

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Originally Posted by boatbod View Post
One other thought: when you de-bonded the keel, did you make sure the vhf antenna on the mast is not grounding out (through the braid and bracket) back to the keel via the lightning ground?
hmm.. this could certainly be an issue. I have an inline connector on the VHF at the base of the mast. The PL-259 connector sits on my mast step an inch from the lighting wire.. I will wrap that up in electrical tape!
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Old 06-05-2017, 13:22   #36
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Re: Electrical Leakage Checks On The Hard?

Quote:
Originally Posted by estarzinger View Post
Yes, there are. You can check resistances across your system (with a good multimeter - with long probe leads).

First check that your keel and thru hulls are actually unconnected to the DC systems (negative and positive) - normally one would check AC also but sounds like you dont use it much. You want a complete open circuit. Sometimes there are 'hidden' connections, and sometimes there is enough salt and other conductive 'dirt' to make a connection. If you find anything other than a complete open circuit here - track it down, clean it up. (this all can take some time if you have a bunch of wires).

Second, check the resistance between the items that are bonded and electrical system - should be very low to negative battery post.

Third, check the resistance across all your active connections. Start from the battery terminals one probe on the negative (check from the positive side after done with the negative) and move your other probe out along each circuit and check resistance after every connection (or as frequently as you can). There are benchmarks for how much resistance to expect per meter of wire and per each crimped or soldered connection . . . but really just look to keep the numbers low and if you see a significant jump up you know you have a connection (or whole wire) that needs to be cleaned up.

It would not be usual to find several connections that need redoing, and in an older boat - entire wire runs that need replacing.

The bottom line is: if your system is designed/wired as per the stan honey article* linked above in thread, and your connections are clean and low resistance, and 'unbonded' stuff is actually unconnected . . . then you have done about as much as you can.

There are benchmarks for how much zinc you should have on the outside of your hull. I am presuming you have an iron keel, and there are standards for zinc (both weight and spread I believe) per surface area. Id have to google up the tables and you can do as easily as I could. But for my aluminum hull (which was floating/unbonded) I had a dutch standard for this - the french used a different much lower amount of zinc - leading one to believe that these 'standards were up for some amount of debate.

* note: there are some detail different between abyc and stan honey and Nigel Calder - I have talked with all three, and they make some slightly different trade-offs. That is they all three have sounds reasons for their way of doing things. Personally I follow Stan, as by far the most intelligent and thoughtful and 'engineering experienced' of the three 'schools'.
THANK YOU!! this is exactly what I was looking for. I will do some checking per above. My keel is Lead btw.. I run a pair of standard 1in shaft zincs, so nearly 2 lbs of zinc.
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