Rising Tide on the Mireille

Your narrowboat, the Mireille, is moored at Crofton Cut — barely. A summer storm is rolling in from the west, and the canal lock ahead has begun malfunctioning: water is flooding backward through a faulty sluice gate, rising fast in the lower pound. The only way through before the storm hits is to flood the Mireille's galley bilge-tank in a precise sequence to match the lock level, then open the manual bypass. You have twenty minutes. Maybe less.