Two good lessons. (1) Restorations are almost always far more expensive than just buying a similar boat that has been well maintained. (2) Group boat ownership is often a good idea, you can share the finances and no one actually ends up using the boat as often as they think they will.
That works well if you're all the type to just putt in a circle outside the harbor. If some of the owners are the type to beat the vessel up doing what it was intended to do and more and some of them aren't you will wind up with hard feelings when things break.
If you are trying to bounce off 6ft surf (emphasis on "off" rather than "through" in a tri-hull) that will eventually come back to bite you in the form of tearing the vessel apart at the seams. If you are constantly beaching something with a deep V you can only go so long between events where the prop/lower unit unexpectedly finds the ground (and eventually that will get expensive). So you either share the cost of these repairs with the understanding that that's just the cost of doing business (because simply based on your varying use somebody will have to be more abuse to the vessel) or you all get your own boats that fit your use cases.