Bay seniors who can’t wait for the Sing-a-long Messiah should drop by SF’s Maritime Park this Saturday (and the first Saturday of every month) for a sing-a-long of seaworthy chanteys aboard one of the historic vessels anchored there. The program runs from 8pm to midnight. Hot cider is dispensed to ward off the Bay chill. Reservations are required. It is otherwise free. The deco Museum itself is open during the day for you to admire the great WPA murals, though renovation is incomplete and the collection of nautical memorabilia still in storage.