Numerous reports indicate that the Germans have found the use of smoke screens at night to have considerable protective value against enemy bombing attack. This has been particularly true of the coastal areas, where unscreened coastlines offer a ready means of calculating distances accurately. In inland areas, where targets are not so easily located, smoke screens are generally limited to the protection of precision targets of prime importance. However, there are indications that several of the larger inland cities are protected in this way. In addition, decoy smoke screens have been effectively employed upon a number of occasions to protect nearby targets.
Relatively few instances of daylight screening have been reported to date, and on the whole the practice has not proved particularly effective. With the increasing frequency of daylight raids over the Continent, it is to be expected that the Germans will take steps to protect vital target areas with efficient smoke screens both day and night.
The Germans have used smoke extensively for screening:
(1) Battleships, docks, and naval installations;
(2) Oil refineries and storage;
(3) Important blast furnaces, factories, and buildings;
(4) Canals and harbours.
The most exact knowledge of large-scale smoke operations comes from Brest, where several large German battleships and cruisers were successfully protected from enemy bombing over a very considerable period of time. A screen was put up immediately upon the sounding of an air raid warning, and within 20 minutes the docks and town were completely enveloped in smoke. It is reported that the screen was so dense that visibility on the ground extended for only a few yards.
Quo Fata Vocant-Whither the Fates call