Coast Guard District narrative histories 1945
"Blackout" entered the universal vocabulary with the advent of World War II, although, it had, in some degree, been used in all previous wars. The blacking out of municipal lights became the activity of the Civilian Defense Organization, but the problem of extinguishing lights on river and railroad bridges and the blacking out and silencing of navigational aids fell to the Coast Guard. Accordingly, The Commandant advised all Districts in October, 1940, that plans for the extinguishment of lighted aids and the silencing of sound signals were to be prepared in the event of a serious national emergency. In the 13th Naval District, a Board was immediately organized for the purpose of making a study of meeting any emergency which called for the purpose of interruption of the operation of navigational aids in the Seattle District, including all Canadian aids in the Strait of Juan de Fuca. The District Coast Guard Officer ordered this Board to study the Strategic areas of the Columbia River entrance, to study several bar harbor entrances, San Juan Islands and the Puget Sound Area, and to formulate a Blackout Plan. The Plan was submitted to the Commandant, 13th Naval District for approval, as the Coast Guard operated its blackout through the Senior Naval Officer of the District.
This Blackout Plan, as approved in September, 1941, divided the District into seven areas, designated as Blacks One to Seven, and each Black was further subdivided into seven sections indicated by letter so that any part of any area could be blacked out separately. The "S" Code, developed previously by Communications for exclusive use in this District, was enlarged to accommodate blackout activities in all communication between Coast Guard units. For example, if all aids in the District were to be blacked out, the "S" signal was "Signal 26"; if the lights were to be blacked out and the sound signals silenced, the "S" signal was "Signal 138". If a blackout was designated in Black One Area, the signal was "Signal 26-1A", etc. An "S" Code Signal Book was published for issuance to all units. Appropriate "S" signals were also prepared for the relighting of all aids.
Radiobeacons were not silenced under the general blackout but were covered by individual instructions to the Commanding Officers as required. Although an effort was made to cover all aids, it was understood that aids omitted or aids established after the Plan was distributed were to