The Glomar Explorer wasn't unique because of it's mobile derrick. There were any number of ships designed for that purpose. It was notable for its deep sea mining of exotic minerals, such as manganese. To date, there still isn't a ship capable of doing such a task and this particle ship was positioned in a public school textbook as having done so.

No, it was scrapped in 2015 at a Chinese shipyard.

I really wouldn't take their word for it haha