I have a new to me sailboat that my surveyor stated the wiring both DC and AC are a mess, but a 30 year old boat I wasn’t surprised and not too concerned. I’ve rewired boats and cars in the past and feel comfortable (I thought!) with the DC side more than the AC. Trying the move the boat from the seller’s marina to my marina, I got a shocking surprised.
The existing GPS had a bad power cable, so I replaced it and for our trip, I temporarily wired it right to the battery. Worked fine at the dock, shore power plug in, motor off. Disconnected the shore power but crew did not turn the AC power switch off, started motor, the GPS started flashing transducer is off! Concerned but not overly, I proceed to the fuel dock I place the boat in gear, slipped off the insulated part of the gear shift and hit the steel and zap!!! Raised the RPM to move forward and bigger zap! Back to the slip to regroup. Some observations, I have an AUTOMAC II, I understand the function but do not completely follow the wiring, but does have an AMP meter with it and prior to this trip shown charging, after the shocking, it appears no current.
My first step was to isolate the house wiring from the motor, I now have only the motor on one battery. Now I’m not shocking, but then again, now I don’t have any charging from the alternator/regulator. I’m guessing I now have a bad alternator, but I still not sure of the possible cause. I don’t want to replace the alternator only to blow out another. Any suggestions to the potential cause of the stray current? I have some of MaineSail’s diagrams to take down on my next trip to review, but I’m hoping to develop a plan before my next trip. Any help would be appreciated, thanks
The existing GPS had a bad power cable, so I replaced it and for our trip, I temporarily wired it right to the battery. Worked fine at the dock, shore power plug in, motor off. Disconnected the shore power but crew did not turn the AC power switch off, started motor, the GPS started flashing transducer is off! Concerned but not overly, I proceed to the fuel dock I place the boat in gear, slipped off the insulated part of the gear shift and hit the steel and zap!!! Raised the RPM to move forward and bigger zap! Back to the slip to regroup. Some observations, I have an AUTOMAC II, I understand the function but do not completely follow the wiring, but does have an AMP meter with it and prior to this trip shown charging, after the shocking, it appears no current.
My first step was to isolate the house wiring from the motor, I now have only the motor on one battery. Now I’m not shocking, but then again, now I don’t have any charging from the alternator/regulator. I’m guessing I now have a bad alternator, but I still not sure of the possible cause. I don’t want to replace the alternator only to blow out another. Any suggestions to the potential cause of the stray current? I have some of MaineSail’s diagrams to take down on my next trip to review, but I’m hoping to develop a plan before my next trip. Any help would be appreciated, thanks
