I'm picturing sailing decks G or C for galleys, C or A for gunboats. A rowing vessel must come to a complete stop before pivoting and may pivot up to 90 degrees. Pivoting vessels move before all vessels using cards. A vessel that has pivoted may move at a speed of 1 using a card on the next turn. Galleys and gunboats do not need to plan two cards ahead. They only plan the card for the upcoming turn.

In reverse, they cannot move at greater than speed 1 or turn tighter than 7/3.