I would like to point to an interesting website about sailing in Croatia: Adriatic Croatia International Club | ACI Marinas
gives you a good overview about the aerea including basic nautical informations, port facilities, local weather conditions and so on - all in English.
Additionally, I may disadvise you to go there from now until 15th of August. Due to summer holiday in Italy (Feragosta) there are thousands of motor boats crowding all ports and sailing there in this period is not a pleasure. If you think about a charter trip in Croatia you should choose any week after 15th of August until the end of September. In spring you will find perfect conditions during May and June.