First decide what scale you would like it to be, then go looking for figures either that scale or the nearest smaller. Also figure out how tall your figures need to be, then go looking in toy shops.
Most real sailboats with crew have a crew that can get out of the way of running rigging and duck out of the way of swinging booms. Anything that can can possibly snag running rigging on a model sailboat will do just that art the least convenient moment.