Be sure
I grew up at the marina my father built. We did a great deal of winterization. Typically, we did it because the boat owner wasn't confident about how to go about it. I suggest you slowly and methodically look at the systems one at a time. My guess is you only have two or three seacocks. With your boat on shore you can inventory them from the outside and then go inside and follow them. Odds are your fine. Something you didn't mention but might want to check is that one of the lines does not have a low spot in them where water might settle, freeze and crack the pipe. I typically send a little pink antifreeze down the drains just to be sure. Hope this helps a little.
