you know how many pby's were actually active as "black cat's"? wasn't 4000, or even 400...
vp-12 had 5 operational radar equipped pby's starting in december 42 to feb/mar 45...over 200 missions. 5 other squadrons were subsequently outfitted with similarly equipped pby's...in limited quantity. patrols were not performed by full squadrons at any one time, with the greatest successes in night operations.
the majority of wwii pby's (series 1-6) served in s.a.r., recon, training and domestic patrol roles...due to their documented vulnerability to japanese fighters in the daylight.
u.s. navy pby units of the pacific war, louis dorny. black cats and dumbos, mel crocker.