I was on a cruise about a year ago which had a knitting craft class aboard. There were about two dozen women who had booked it through an organizer, with one instructor and her helper. She offered a series of four "workshops" on specific topics over the course of the 7-day cruise. I think that each of them was presented twice. I remember that one of them was on creating a beaded scarf without pre-stringing all the beads. Just about all of the women had brought along a project of their own, though, and the instructor was no help at all on anything except her presentation topics. I know this because many of them would congregate in a corner of the library during spare moments, and help each other. I was not part of the group but wound up helping a woman who was trying to make socks for the first time.
I've found that most ships will schedule an unhosted needleworkers get-together if anyone asks them to. There always seems to be at least a dozen people who are happy to chat while they work, and are more than willing to share patterns and assistance. There's really no need to pay extra for a hosted craft class on knitting.