Petty Officer 3rd Class Preston Cummings, a boatswain’s mate in the Coast Guard Cutter Polar Star deck department, signals the distance of an approaching ice shelf to the coxswain of one of the cutter’s landing craft in McMurdo Sound, Antarctica, Feb. 6, 2016. The Polar Star’s two landing craft are designed for use in ice coverage that would be hazardous to most cutter boats. (U.S. Coast Guard photo by Petty Officer 2nd Class Grant DeVuyst)