Audio Systems: marine audio, metal chassis, marine stereo

Question
I'm installing a new marine stereo system on my pontoon boat.I followed the wiring istructions but run into a snag when it comes to the common groung. where do you ground it on a metal frame pontoon. I tried to ground it to the metal frame with a screw. no luck. Can you ground it back to the negative post on the battery

Answer
exactly :)
That may be your only 'ground' since the battery is probably not grounded to the metal chassis you are trying to use for a ground. It may be attached at some point and that would work (you might try a meter and probe for a ground).. but it will have to get back to the neg terminal one way or another.

JM