Banning Coast lights and airplanes were used to spot U-Boats
Explanation:
British experience in the first two years of World War II, which included the massive losses incurred to their shipping during the "First Happy Time" confirmed that ships sailing in convoy — with or without escort – were far safer than ships sailing alone. The British recommended that merchant ships should avoid obvious standard routes wherever possible; navigational markers, lighthouses, and other aids to the enemy should be removed, and a strict coastal blackout be enforced. In addition, any available air and sea forces should perform daylight patrols to restrict the U-boats' flexibility.
