The crew of the Coast Guard Cutter Shackle (WYTL 65609) transits up the Penobscot River in Maine to break ice on Feb. 16, 2022. The 65-foot small harbor tugs are multi-mission cutters. Their primary missions are domestic ice breaking, port security, search and rescue, and law enforcement operations on rivers and inland areas. (U.S. Coast Guard Photo by Petty Officer 2nd Class Ryan L. Noel). 220216-G-IY621-0612