brian whatcott wrote:
On 7/20/2010 10:10 PM, Stephen Trapani wrote:
I lost a zinc on my prop shaft very quickly. My boat is moored with only
one other boat within miles. The only possible source on my boat (I
think) is the bilge switch in my bilge because it is the only thing on.
The connection to the switch is out of the bilge water, so it can only
be coming from the switch itself. I have a voltmeter. Is there any easy
way to test to see if the switch is leaking current?

Here's a quicky check: with no connection to shore power at all, find a
meter with a sensitive current scale like 50 microamps. Find a lighting
cord and connect the two wires at one end to the battery terminals. At
the bilge, connect one battery lead to the meter and dangle the other
meter lead in the water, preferably though a scrap of stainless sheet.
Check the reading.
Now connect the meter lead to the OTHER battery lead and dangle the
other meter lead in the bilge again. If you normally leave the boat
connected to shore power, repeat these two steps with shore power
reconnected.

Not a complete check, but it can catch many leaks.

My apologies, but I don't understand. If I have both leads connected to
the positive and negative battery terminals on one side, which one do I
hook to the meter and which do I dangle in the water, and how would
there then be one dangling from the meter into the water?

Stephen