Voltmeter and condition of Skin Fittings

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alec

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Is it possible to determine the condition of Skin Fittings with a voltmeter ?

In the distant past I seem to remember a way of testing metal fitness. You used an Ohms Meter connected between the engine and the Skin Fitting. If the reading was more than one ohm a problem may exist.

While the boat is out of the water, it would be nice to have a secondary test rather than just visual. I do have some Blakes type fittings with a hint of pink.

Just for the hell of it, I placed a voltmeter between two bronze type fittings on the hull and a reading of 1.8 was given with the Voltmeter Range set at 200mA. None of my fittings are connected. Does this have any meaning other than they may be two different types of bronze ?

Thanks in advance.
 
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I placed a voltmeter between two bronze type fittings on the hull and a reading of 1.8 was given with the Voltmeter Range set at 200mA

[/ QUOTE ] Volts or mA ???

I assume you mean the meter was on the 200 mV range and you measured 1.8mV. What does it mean? nothing significant I would think?
 
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I placed a voltmeter between two bronze type fittings on the hull and a reading of 1.8 was given with the Voltmeter Range set at 200mA

[/ QUOTE ] Volts or mA ???

I assume you mean the meter was on the 200 mV range and you measured 1.8mV. What does it mean? nothing significant I would think?

[/ QUOTE ]

Thanks for the response Vic !

Yes, the meter was on the 200mV range and measured 1.8mV.

On the other stuff, I wonder if I'am getting mixed up between ohms and volts. I assume that ohms meters exist ?
 
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I assume that ohms meters exist ?

[/ QUOTE ] They do and multimeters usually have several ohms ranges.
 
Is the boat out of the water NOW?
You were measuring milliamps between two fittings which suggests a potential difference (voltage ) between them.
This shouldn't be there, certainly if we're high and dry.
It doesn't reflect the condition of the fittings, it indicates a situation which could cause deterioration over time. Maybe you need to wire all the fittings together -some boats do, some don't.
 
I would not bother. The main test is to re-grind them with coarse paste, really hard. If the cone continues to show a lot of pink after you have removed material then it is suspect. However, all the skin fittings I have destructivley tested, and also cut and polished the edges for a good look at the condition, have been remarkably good. I think they would have to be really knakered to actually break off.
This is the Blakes type. Threaded flanges, gate valves and ball valves I would just change every 10 years. Blakes every 40 to 50, but their bolts every 10/15!
 
I am not too wised up on electrics, so with regards to skin fittings I only use my ohms setting to check my anodes.
 
Thanks for the input chaps !

Just had a look at my multimeter. The ohms sign looks like a pair of headphones and you can set the test at the desired range. I will give it a go just to see.

Have found the piece on using an ohms test :-

'Ground a wire a wire to the engine and lead it over the side near the metal part in question. Touch the end of the wire to an ohmmeter that is in contact with the metal part. A reading of more than 1 ohm signals that the part may be deteriorated and should be examined carefully'.

Just for info - I have had a good scratch at the four Blakes types seacocks and they are bright without any pink in them. The problem - if there is one, is the outside plate which has a touch of pink. About seven year's ago, I had all the seacocks out re beded them and used new silicon bronze studs.
 
I wired the volktmeter to my wifes fingers, and asked her opinion of the skin fittings. She said they were fine, and the volt meter said she was not lying.
 
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