Jean-Marie Grosclaud was the French captain of His Most Christian Majesty's thirty-two-gun ship Railleuse. Grosclaud was among the commanders who participated in the blockade of Lübeck Bay from the fall of 1633 through the spring of 1634. However, Grosclaud and his crew suffered a harsh Baltic winter weather as well as poor diet, inadequate clothing, poor sanitation, nonexistent hygiene, miserable, wet, unheated living quarters, and treacherous conditions aloft, which left many men killed by attrition. Grosclaud finally decided he'd had enough and piloted the Railleuse for France.