By Frank Hartzell The big boat maker has seen rough water since its latest financial report. Selling boat parts and club memberships has helped empower one boatmaker through a year of high demand and supply shortages. At the end of January Brunswick Brunswick (BC) – Get Brunswick Corporation Report posted a top- and bottom-line earnings beat with a strong outlook for the remainder of the year. Boating demand surged throughout the pandemic, even outrunning supply by last summer. CEO David Foulkes told Jim Cramer on the Mad Money TV show at the time that Brunswick has many growth levers at its d…