Sunsail, for many years, ran courses for people wanting to charter but without enough experience. They were usually out of places where they ran a beach club as well. The plan was you did the course in the first week and then had your own small monohull in one of their flotillas during the second week (or on a subsequent vacation if you couldn't do 2 weeks). They were never really advertised but existed for many years. Contact them and see what they say.