I have litigated numerous ownership breakups, mainly businesses, but also assets like
vacation homes,
boats, etc. Some general observations:
1. Ownership should be though an entity, such as a corporation or LLC. That protects you against your "partner's" possible negligence.
2. If things go well, well that's great --sometimes things do
work out!
3. Make plans for succession. If your partner dies, who gets that share and what are their rights. A lawyer helping you put the entity together can walk you through the ways of handling this.
4. As others have said, it is best to be clear on potential points of disagreement and how to resolve those, such as escrowing money for and deciding when it is necessary to do updates or
repairs, and how to schedule taking turns using the boat.
5. Hope for the best, but assume that things will not work out at some point and prepare for the worst. To avoid litigation, include worst-case procedures in your agreement.
6. A common provision is a buy-sell provision. If you can afford it, this is a good way to resolve disputes -- when you reach an impasse, you name a
price and either your partner buys you out for that
price or you buy them out.
7. If you can't afford to buy out your partner in an extreme case, then another common provision would allow you to force a public
sale -- if you reach a point where going on together won't work, you can agree in that case the boat will be put on the market and
sold within X number of days or months to the highest bidder. Either partner of course could also bid in that case. You have to be prepared for a possible
sale at a loss.
8. Also consider where the boat might be and get a knowledgable lawyer to advise you on the mechanics of enforcing an agreement if the boat is in distant lands.
Obviously, I think that boat sharing could work well as long as partners remain in agreement, but should have strong protections in case of disagreement.
Not quite on point, but illustrating my concerns, we once had a couple who split ownership of a nice house on a very nice beach. After many happy years, the two sets of owners came to blows. We worked hard for many months to bring them to agreement (while they were paying substantial fees) and eventually got everyone to come to the table to sign off on a settlement. Then at the planned closing it turned out that there was a wooden pelican by the front door that we had not talked about, and the whole settlement fell apart because they could not agree on who got the pelican .
Hope this gives you something to consider.