Re: Engine start shuts off chartplotter
No need for a starting battery if you clean up the existing problems, mainly putting in a good ground point and getting rid of the JB Weld kludge job. You might also take a good look at cable sizing and condition, make sure the battery cables (hot and ground) are adequately sized and not corroded anywhere.
It is pretty common to put the VHF on a fuse/breaker of its own, because you don't want ANYTHING else to be able to trip the breaker and kill your VHF in an emergency. But then, the rest of the electronics are usually fine being lumped on one circuit, which makes it simple to turn them all on/off at once. So, there's nothing "wrong" about the way they've been split up.