I think I finally have figured it out.

I checked the conenctors, and it looks like some of the plastic melted and shorted things out. So it looks like the next order of business is to upgrade everything to Deans plugs.

The ESC is hard to tell with the scale, but it is made specifically for boats from Rum Runner Hobbies. It is rated for up to 14 cells and 85 amps.

Thanks again for listening to my story. I guess I should have asked first but....... live and learn.