. "An emergency main ballast tank blow is a procedure used aboard a submarine that forces high-pressure air into its main ballast tanks. The high-pressure air forces ballast water from the tanks, quickly lightening the ship so it can rapidly rise to the surface."@en . . . . . . "Emergency main ballast tank blow"@en . . "An emergency main ballast tank blow is a procedure used aboard a submarine that forces high-pressure air into its main ballast tanks. The high-pressure air forces ballast water from the tanks, quickly lightening the ship so it can rapidly rise to the surface."@en .