Nick,
I remember reading about the Freestyle 474 in mags back in the 80s. Never actually seen one.
From memory it was a one man boat. If you add a jib and crew in addition to Gary's wise comments check the bouyancy in the hulls or be very carefull with the weight of the crew you sail with.

Good luck.

Regards,
Phill

I know that the voices in my head aint real,
but they have some pretty good ideas.
There is no such thing as a quick fix and I've never had free lunch!