Originally Posted by mitiempo
This is DC so a main breaker is not needed......
Not sure what you mean by not needed. If you mean that separate breakers are not absolutely necessary to safely protect a circuit, I agree.
However, in the event of smelling an electrical fire (the most common form of boat fire), wouldn't you want one master switch to kill it all? In addition, if you're up on the hard or away or just need to kill all parasitic loads, a master is very helpful. That may not be a breaker, but often goes through a kill switch of some kind.