The Answer
A bit over a week ago I posted an electrical quiz question.
A couple of members came close in the comments, but no one got it exactly right.
Answer
I had the volt meter connected between a reference anode, immersed in the water next to the boat, and the boat’s bond system, and was looking to see if the meter kicked when I disconnected and reconnected loads and charging sources from the main positive busbar.
If the boat had been metal I would have been connected to the reference anode and the hull.
The clues to the right answer were that I was measuring volts, not amps or continuity, and that neither of the meter probes are present in the picture.
I’m pleased to say there was no kick, but if there had been, that would have indicated stray currents flowing from the battery positive, through the connected piece of gear, through the water, and back to the bond system, and eventually the battery negative—we must always think about circuits.
This is a good test to perform regularly on any boat and that goes triple for metal boast and those with saildrives.
Further Reading