biko01 asks: "Are there any reliable platforms or communities where people post about co-ownership opportunities?"
Well yes, there is this one for starters :-)!
But of course any counsel you may get in regard to "co-ownership" of a 10-ton
boat of the type you list, in the
Mediterranean far from home, is likely to be discouraging because it simply cannot be a sound business proposition.
As you know, I'm sure, assets may be owned by one of three kinds of entities - sole proprietorship,
partnership or incorporation. You can call a
partnership a "co-ownership" if you like, but the law will not be fooled — it is a partnership with all that that implies in terms of
legal liability. In short: If your partner screws up and incurs
legal liability, YOU will have to do it for him if he either cannot or will not do it himself!
The same is true seen from the perspective of your "co-owner", of course. So ask yourself if you would be happy to enter into "fiscal marriage" with someone THAT naive :-)?
Why would you put yourself in so invidious a position when you don't have to?
You don't want a closely held corporation" either, because in jurisdictions rooted in
English Law, "closely held corporations" are perceived by "the law" to be mere "partnerships in disguise" employed by naive shareholders for the purpose of dodging the law relating to partnerships.
The mere asking of the question you ask, which does get asked now and then, usually indicates that the enquirer is "over-reaching" either in terms of financial competence or seafaring competence. That may not be true in your case but think about it!
Bonne chance :-)!
TrentePieds