The Germans decided to cancel production of heavy water at Rjukan, and move the remains of the potassium hydroxide—from which the heavy water was distilled—was to be transported to Germany. The resistance movement was aware of this plan, and considered blowing up the train at various places, but instead chose to target the ferry SF "Hydro. The night before the shipment went the saboteurs entered the ship and placed a bomb in the hull, timed so the ferry would blow at the deepest point of the lake, but at the same time close to land to help save the civilians on board. The attack was successful, the ship sank to depth with 47 people on board, including eight German soldiers, a crew of seven and the cargo of heavy water. 29 people survived.