BBC News carries a nice story on the JAMSTEC monster ship Chikyu, also called “Godzilla-maru” for obvious reasons. The ship itself is 210 m, but the drill derrick rises 100 m off the deck. The rig dwarfs the Statue of Liberty, nearly matches the height of the St. Louis arch.
Chikyu’s destiny is penetrate the Earth’s mantle, 6 or 7 km below the seafloor, 1600 m deep and more. Operating costs are astronomical, on the order of hundreds of thousands of dollars per day. The BBC story features several nice illustrations and videos detailing the ship’s operations, including this one here.