Hehe, is a hovercraft without an air cushion called a hovercraft? He mainly relies on air cushions to isolate contact. Think of the inflatable rainbow arch at our wedding celebration. In fact, it has been leaking, but it has been expanding, so it bulges. If it is not started, the air cushion will disappear automatically and become a layer of cloth. Ships like the European bison have enough endurance, and when they are not driving, they can float on the sea surface by their own buoyancy, so they can be towed even without oil. It is enough to rely mainly on your own endurance.