Weems & Plath's "The 12 Volt Doctor's Practical Handbook for the Boat's Electrical System" by Edgar J. Beyn. You may think that making a wiring diagram for your boat would be a monstrous headache, and the results as useful a a street map of Brooklyn viewed from ten feet away. But read how simple it is when you take small steps, one area and one sketch at a time, whenever you happen to look at a particular detail. Eventually, you will have a collection of sketches which is your wiring diagram. Will mail to a USA address for $2.66