It was necessity which obliged the Japanese to supply their positions and outposts ashore almost exclusively at night. Their ships and barges moved mostly in small convoys guarded by one or more combatant vessels. These operations were carried on throughout the area and it was virtually impossible for U.S. surface combatant forces to stop them.
Ironically, it was also necessity which had turned the PBYs into night creatures. Their slow speeds, which rendered them clumsy and vulnerable by day, made them agile and surefooted by night. Radio altimeters allowed them to skim the dark surface of the ocean where fast fighters feared to tread. Their size, which made them easy daylight targets, enabled them to carry large quantities of fuel and weapons, and to range deep into enemy-controlled areas after dark. They could remain aloft all night, searching out their prey with electronic eyes or lying in wait at strategic points. The Black Cat concept developed naturally through the survival instinct and the determination to strike back against a cruel and unrelenting enemy. No one man or group can be given credit for its genesis. It was the result of the contributions and sacrifices of many, a combination of courage, technology, and the hard lessons of combat.
Aubrey Fitch was now ready to use this capability aggressively against the "Tokyo Express." He had already decided to officially designate one unit a Black Cat squadron and deploy it to a forward area to evaluate the idea. Its planes would take off at dusk and return home at first light. All aircraft in the squadron would be equipped with radar and radio altimeters, and painted with non-reflective black paint. Even the aircraft side numbers would be obliterated so as not to provide a focal point for enemy searchlights.
(The above section of text was taken from "Black Cat Raiders of WWII" by Richard C. Knott, 1982)(now out of print)