Hi,
Many years ago we partnered with a friend couple on a motor boat-Fortier 26' for fishing in Narraganset Bay, we both had 2 small kids at the time, shared the agreed on purchases based on need( you know boat won't go, vs boat not pretty, 50% each including gear such as fishing poles, dinghy etc. It worked out well to each reserve weeks for vacation, but we also enjoyed putting the 8 of us on and enjoying weekends together. As I said, we knew each other well, knew the jobs we each were capable of performing and the summer in New England was pretty short. No lawyers were involved. Then we went our separate ways when the time was right. We bought a cruising trawler and they a Pacific Seacraft. We split the goods from the boat and "profit". It can be done, I think.