Bob Foster of Sarasota, Florida, asks:
“Last week, while my wife and I were cruising, our windlass motor suddenly stopped when I began to pull up the anchor. At almost the same moment, my wife shouted that she saw smoke coming from underneath the nav station. When we got home our local marine electronics technician told me that some of my electronic gear had been damaged as well. What happened, and how can I avoid a repeat performance?”
Gordon West replies:
It sounds as though you have a poor negative battery lead connection on the windlass circuit. When the windlass was working hard to break the hook free (which is not a good way to use the windlass, but that’s another story) resistance in the negative lead caused current to be pulled through the boat’s ground system, which is joined to the battery’s negative side.
Whenever you pull current through a ground system, there’s a chance it will travel up the negative lead of any electronics equipment sharing a common ground connection. Some marine electronics have fuses that prevents a damaging current from burning up the smaller black ground wire for this very reason. I would guess that your windlass’s black wire is badly corroded. I suspect you also probably saw some melted black wires in your electronics package. If you replace these wires properly (I suggest having a professional do the rewiring), your electronics should work correctly again. Your electrician should also look at the existing wiring for the windlass. Presumably he can rewire the unit so all the current needed to power the motor flows along the red and black wires, and not through the common ground connection.