Re: sailboat nav lights
a sailboat with a motor running is a motor boat.
Under 26 ft, the minimum you need is a red/green on the bow, and an all around (360 deg) white on a 4ft pole on the stern. Just like a 16 ft skiboat would have. You don't have to have a mast light(called a steaming light). The all around white on the stern qualifies for that. Do it on two switches though because if you anchor, you're supposed to turn off the red/green running lights. If done with all LED light's you won't pull squat for amps and a smallish battery will do, but PERSONALLY, I'd have to throw in a stereo, and more lighting for camping, so I would carry more battery!
Good luck, I just started overnighting on my sailboat too and having a good time.
Jim