reverse polarity

I installed new batteries and connected the polarity reversed (red wire to neg and black wire to positive) and started the boat, which did not start. I connected the batteries correctly and all the electronics seemed to work but the boat did not start. However, I can hear a "click" (engine...

Does anyone know why the light would come on when I connect to shore power and test (with the switch on the panel). When I use the tester (from HD) in the outlets on the boat they show all correct. Everything works OK except the meter does does move. :huh: