When I played the Battle of the Nile I let another ship that came to a halt close to a ship that ran aground pass a cable (1 turn) and then each following turn draw two 50/50 chits. If both were hits the ship was dragged off and could plot movement from the next turn. Ship of the line had to keep a (full? half? can’t remember but it was quite obvious when it was set up) ruler from the shore and the frigates half that. I assumed it was a sandy bottom.