As a Ships' Captain I will recommend that you secure your vehicle within a shipping container. Ship's do roll slightly in any seaway, during a sorm I have personally recoreded a 20 degree roll. The handling of the containers in certain ports leaves a lot to be desired. Yes containers do have some securing pints in them and generally they are located at the sides of the floor in the container and right against the side of the container. You will be responsible for supplying the securing gear.
The best advise that I can give you is to use a minimum of 6 two ton ratchet straps (cargo straps). Secure one from each wheel so that they criss-cross under the vehicle with the forward once leading aft and the aft once leading forward. Use the other two, one for the foreward end and one on the aft end, arond the axles. these two to lead away from the vehicle. Other products such as air bags can be used to cushion the vehicle between the sides of the con tainer.
The last, and most important advise that I can give to anybody who intends to ship a vehicle or motorcycle, it is vital that you take out decent insurance.
Have a save journey.