We have read a great deal, and discussed with experienced degree level electrical engineers, and a properly qualified ( engineering and nautical science degrees and years of metal boat experience as a Coastguard Engineering Officer in the engine room.....
Also written to Brent Swain about what he does.....
We have on our steel hull,
A double breaker system, breaking both the positive and negative of the 12 volt circuits.
Not really necessary if the normal single breaker system is well wired and there is no chaffing of cables.
It is believed necessary to have a return to the steel hull in at least one place in order that a fault in the wiring of an appliance, or cable chaffing, will complete a circuit and trip the breaker.
No circuit no tripping!
Large vessels often have blinking light to indicate ok condition, continous to indicate faults.
With a steel hull using a 1/2 silver cell and meter will allow for accurate reading.
One end with the silver cell is lowered into the water, the probe attached to parts of the metal vessel, and low level voltage reading taken.
With an adequatly zinced vessel the reading should be in the region of 0.5 to 0.6 volts which will indicate neutral as the salt water is providing most of the voltage in contact with the silver. ( Check the reading given here ....... I do not have my manual with me)
Although a regular multi meter will work the 1/2 silver meter is better.
See this site for info on checking for hot spots on a fibreglass boat....
www.protroll.com/books/?id=5&p_id=4
Measuring in brackish or fresh water will give different readings.
My friend borrowed my meter set up and took it around his aluminium sailboat, and then offered to measure the metal boats at the ddock. Many owners didn't want to know the results.
If in doubt check metal on an old dock,(will not be protected by zinc) and a well kept new metal boat for its voltage.
Hope this helps.
Perhaps you would like to post your voltage readings.
Linear Mode
