One must pack for shipping keeping in mind that the shipping company employees do not have the same interest in your shipment that you do. It is always better to pack so the shocks will be carried directly into the strongest part of the object. In the case of the naval carriage cannon, there should be runners under the carriage that directly contact the cheeks so the load is not carried by the axles and wheels. The wheels should be up in the air enough to guarantee they will not contact anything during shipping as many items are sent through conveyor systems where they fall from one belt to another, or are simply thrown around by the handlers. One should never ship a barrel mounted on a carriage; they should be shipped separately even though that is more expensive.
Money spent on building strong packaging that limits movement of heavy items is well spent. Typical handling will cause heavy items to penetrate corrugated boxes and they are frequently lost that way. Heavy items should also have their own shipping label directly attached so if the above happens, the item can still be sent to its destination.