You are on a vessel with a 30' mean draft. While maneuvering away from the dock at slow-speed the vessel grounds near the bow area on hard sand. In order to achieve an additional three foot of trim by the stern, you need to shift ballast from the forepeak, which is full, to the after peak, which is empty. Your ballast pump for this operation has a capacity of 85 tons per hour. How much tonnage needs to be shifted and how long should it take?