How wide you want to make it becomes an engineering question. The narrower you make your “hovercraft”, the higher your air pressure needs to be to sit at the same depth, but also the narrower your channel can be, I imagine.
How wide you want to make it becomes an engineering question. The narrower you make your “hovercraft”, the higher your air pressure needs to be to sit at the same depth, but also the narrower your channel can be, I imagine.