What a steal!
Good on ya, tap! I'm no electrical wizard but I don't think you could go wrong with Nigel Calder's "Boatowner's Mechanical & Electrical Manual" (which is sold in the Catalina Owners store). I suppose the first step would be to determine what your needs are - do you really need seventeen lights or will two suffice? Do you need shorepower? Do you want AC power? Inverter? Radio? From there I would think you'd be able to determine how many volts or amps or watts (told you I ain't no 'lectric wiz!) you'll be using which would, in turn, determine the size & how many batteries you'll need.Maybe you should just buy that book and stop listening to me!!!

Congrats on the new boat anyway!LaDonna