The Ship Model Forum

Yes, the light camouflage was the genesis of the Philadelphia Experiment rumors. The light setups were tested both on ships and aircraft (I believe Navy B-24's) and found to be effective under controlled situations, as AR stated, but he amount of lighting and power required was massive. With the wider event of radar, specifically aircraft mounted radar that allowed sub detection from miles away, the program was dropped.

-Devin

The US Navy did "light camouflage" experiments in 1917 or 1918 and again in 1942 using ships based out of Philadelphia (one ship each time). They concluded it did work under very specific conditions but both times came to the conclusion that the lights were not suitable for combat conditions and would be a maintenance nightmare. I wonder if that's the genesis of the "Philadelphia Experiment"?

The same effect was tested on aircraft. IIRC there was a period of brief use by ASW patrol planes.

Re the notes relating to the Dido class.
In early 1941, trials with lighting were conducted on HMCS trillium as a means of cocealment at night.
Initial results were promising ad when Churchill found out, he asked that twelve Home Fleet destroyers be fitted out in the same fashion The reply from the First Sea Lord was that NO destroyersa were available and would not be for some time to come.
Follow up correspondence outlined the problems with constantly changing light conditions, ships course change and target course change. When everything was lined up, it worked well, but a change of angle and /or light made the ship stand out like a Las Vegas casino.
Other problems were damage to the light fittings o the outside of the hull and the brackets and hoods that went with them.
The navy dropped the idea.