The only benefit to co-ownership that I could see is if the goal was simply to charter 3-4 weeks a year every year and either sell the boat at the end or trade in.

Otherwise I think it would get too complicated with one party possibly wanting to own the boat..etc. Although all that could be worked out as well by having a solid contract between all parties that answers all the questions.

I just love the fact that in the past 1.5 years we've used the equivalent of $50k worth of charter time at a fraction of that cost.