Curtis: An inveter produces 120VAC hot to common and hot to ground.
Larry: If this is a name brand marine inverter mfgd and installed IAW ABYC
Standards, then the safety ground and the neutral wire are tied together
when the inverter is producing 120VAC. Assuming that Curtis' receptacle is
wired correctly, I suspect that Curtis is right, he plugged into an outlet
on his friend's boat that had reversed polarity.

73-
Charlie