`` you should need enough ships to throw twenty tons of metal , and six formations , to take the cape long enough to secure the fort again , if they have not ripped it all down , '' she said , `` and when you were done , you should have to leave two of those formations behind with a first-rate 's worth of guns , and i hardly like to think how many soldiers ; and somehow supply them monthly , if the enemy did not have the bright notion of attacking the supply-ships farther north . ''