“Tonging Skiff Gypsy Girl 7,” by Robert de Gast, collections of the Chesapeake Bay Maritime Museum.

In this 1969 image, Tilghman Island waterman Ben Gowe gingerly follows the state icebreaker back to safe harbor after a day’s tonging during a cold snap. In icy winters, the state works to keep the Chesapeake’s principal channels open to navigation and deploys small icebreakers to help watermen return safely to port. Photojournalist Robert de Gast rode the icebreaker while documenting the Chesapeake’s oyster industry in 1969 and 1970 in preparation for a book, The Oystermen of the Chesapeake.