Each boat need to be registered in the DMV if you are using it for Lakes, Rivers and the Ocean. We can get you the CF# for your new boat. A permanent registration number (CF number) is assigned upon registration of undocumented vessels in California. In accordance with the national vessel registration system, the registration number consists of the letters CF, four numbers, and a two-letter suffix (for example, CF 1234 AB). If you own a sailboat over eight feet long or a boat/vessel with a motor (no matter the size), you must register it with DMV in order to legally operate it on California waterways.