Always looking for a way to make at sea resupply more efficient, the U.S. Navy is considering the use of special (more weather proof and accessible) cargo containers. Ships would be modified to allow one or more of these to be mounted on, or in, the deck. The containers would be emptied of supplies as things were needed, and when empty, the resupply ship would remove the empty container and replace it with a full one. In most cases, the containers would contain a standard quantity of supplies all ships need, although special items would still be supplied, in containers or not, as required. The navy has, for decades, been using missiles that are shipped and used from their containers. These "sealed rounds" greatly simplify shipping and use of the missiles.