I shipped my fiberglass pool down with Hyde Shipping out of Port Everglades. It is 15' X 30' X 6'. NO problem. I didn't have to put it in a container.
If you ship the boat consider shrink wrapping it. It's costly but keeps it much cleaner and keeps people out of it while it is sitting around port to port.
Do not ship with fuel.
Theere are some other rules too, I think you have to disengage batteries etc. But the shipping guys will advise you.
Ask for Benny Torres at Hyde. Just google it...