Navy

This is the massive ship that will take the damaged USS John S. McCain back to Japan

The announcement about the McCain's move comes just days after the Navy awarded a contract to a Houston company to move the USS Fitzgerald, damaged in a deadly June collision off the cost of Japan, from that country to a shipyard in Mississippi for repair work. That move could be made in September as well.

The Fitzgerald transport contract solicitation specifically requested a float-on/float-off vessel for the job, using another name for heavy-lift ships.

A heavy-lift ship transports other vessels by filling ballast tanks to submerge its main deck, allowing the cargo to be floated on board — sometimes into a cradle to stabilize it while underway. Once secured, the heavy-lift ship sheds the ballast and sails under its own power. At its destination, the heavy-lift ship reverses the process, allowing the cargo to float off.