6. The Special Training for Dam Busting
For breaching the Ruhr Dams, Barnes Wallis’ science was good and his theory was sound. To go from theory to action, however, the British needed pilots and aircrews with sufficient skill and courage to conduct the raid in accordance with Wallis’ requirements. 24-year-old Wing Commander Guy Gibson was personally selected by RAF Bomber Command’s chief, Arthur Harris, to form and lead a special squadron for that and similar missions – essentially a unit of elite aerial commandos. Gibson’s aircrews trained in modified Lancaster heavy bombers, fitted with a motor in the bomb bay to spin the explosive drum.
The drum had to be released at a height of 60 feet to properly skip on water. To determine the correct height, an ingeniously simple technique was adopted: two spotlights were placed on the bomber’s front and rear, and angled so their lights would meet at the water’s surface when the bomber was 60 feet aboveground. Correct distance would be determined by lining up two sticks on the windshield with two towers to the sides of dam. As the bomber flew in, the sticks would visually be to the outside of the dam towers, sandwiching them. As the bomber drew nearer, the angle between bomber and towers would grow wider, and as seen from the windshield, the towers would “move” closer to the sticks until, at the correct distance, sticks and towers lined up.