What did blackouts during WWII accomplish?
As I have been transcribing letters that were sent to my grandfather in World War II, I was curious to discover many of the measures that were implemented during war time. I can understand rationing, but what purpose could blackout serve? Being a younger person, I could not imagine a time when pilots or mariners actually used anything other than radar and GPS for navigation. Apparently they also used traditional navigation tools such as maps. At night pilots and mariners could navigate using lights from anything from street signs to large cities as a backdrop.
When it came to coastal regions, it wasn't necessarily just air raids that folks were concerned about. They were also worried about background light to shine out to sea which would provide a lighted backdrop to contract ships as they were traveling. Apparently it was a very big problem in the Atlantic and many German U-boats picked off merchant ships like sitting ducks simply because they could see them in front of the illuminated background.
In New York in particular, I discovered there was a bit more to it than just turning off your porch lights at night. Cars were given special lenses that directed light forward and not up into the sky, which caused other problems as well. In addition, homes and businesses had to cover their windows with either drapes, paint, cardboard, or anything else that would prevent light from shining through.
Some locations had strict measures enacted that requested people refrain from even lighting cigarettes, pipes and cigars outdoors as they were afraid the night could aid any potential enemies lurking above. Heaven forbid you actually use a flashlight if you weren't having an actual medical emergency.
I'm curious to think of how we would handle mandatory blackouts now? Mariners and aviators use other tools for navigation now such as GSP and radar, so light isn't the only method to determine your relative location, but how as a society would we handle not being able to shine any lights up at the sky at night? In Great Britain, citizens took blackouts very seriously and offenders were subject to civil action such as fines and even up to imprisonment if they still refused to comply with local regulations.