The ships were fitted with a pair of heavy military masts that carried searchlights. Armed patrols equipped with powerful mobile searchlights monitored the beaches. The radar-guided master searchlights wandered aimlessly across the sky. There was an active light flak battery but no searchlights or barrage balloons. The ANZAC defence was aided by Royal Navy searchlights providing illumination. Four new rangefinders and eight searchlights were installed. They marched under the glow of massive searchlights, bouncing light off the clouds. He also developed optical equipment, for searchlights and telescopes. AA defences improved by better use of radar and searchlights. Its duties were to attack a line of searchlights and attack enemy night bombers. The perimeter of the colony was made up of barbed wire, searchlights, and a watchtower. M2 Browning machine guns, and Sperry searchlights. Blinded by the searchlights, Beattie knew they were close to their objective. Light collected into the PMTs using mirrors from searchlights. Weiler and Gratama set about developing a system for directing searchlights and aiming anti-aircraft guns.