[tcolvin]

Searchlights were controlled both manually and by radar through a Kommandogerät 41/L(uft). In the early days they were controlled accoustically.

The source is Friederich August Greve's book, "Die Luftverteidigung im Abschnitt Wilhelmshaven 1939-1945", which describes the operation of 2 Marineflakbrigade.

Wilhelmshaven and the Jade was one of the most heavily defended areas in Germany. Six FuMG Freya long-distance radars alerted Flak-Ugruko, the system's central control in Wilhelmshaven.

Each Flak battery (and there were 20 under Flak-Ugruko, including two on ships) and its neighbouring searchlight were interconnected and controlled by a dedicated Kommandogerät 41/L(uft), which calculated bearing, elevation and fuse setting for the guns, and also sent bearing and elevation date to the searchlight. Inputs to the Kommandogerät 41/L(uft) came independently from a FuMG Würzberg dish radar and from a FuMG 201 target acquisition device, which in its turn received inputs from a 6m REM optical range finder and from a “Scheinwerferrichtgerät optische Zielerfassung”, a device for taking bearings and elevation visually from the searchlight.

So what bomber crews saw initially was the searchlight beam wandering around controlled by radar, but once the searchlight operator saw an aircraft in the beam, he took control and locked the searchlight on by following manually its frantic twisting and turning. The searchlight then automatically fed the bearing and elevation of the aircraft caught in the beam back to the Kommandogerät 41/L(uft) which passed corrections to the guns.

At least that is how I understand it.

BTW, the Luftwaffe used the same system but called the FuMG 201 a FuMG 41 G (gA).

Tony