It’s one of the greatest sea stories of all time. How Ernest Shackleton, the British explorer, organized the survival and ultimate rescue of the 28-man crew on the Endurance after it was trapped in ice in Antarctica and sank in 1915. Now a team of British scientists is looking for the wreckage while carrying out climate change research there. The S.A. Agulhas II is now cruising toward the Larsen C Ice Shelf, the fourth largest in Antarctica. They hope to put an autonomous underwater vessel under the ice there to measure the shelf’s consistency and thickness. They also hope to find the…