I'm cleaning up the mess out of my boat from my last trip and I get zappped by my aluminum boat. Okay, not really a shock, but I can feel a current running through me if I touch the metal boat and metal workbench. I checked with my volt meter and there is current coming off the boat??? I had the battery charger hooked up but there shouldn't be anything grounded to the boat itself. Never had any trouble with the batteries going dead or fuses blowing. What is going on??