▁forward ▁observation ▁b ubble ▁with ▁an ▁observer ▁seat , ▁a ▁feature ▁often ▁seen ▁in ▁images . ▁ ▁The ▁AN / AS Q - 8 ▁Mag net ic ▁An om aly ▁Det ector ▁was ▁fitted ▁in ▁an ▁extended ▁tail , ▁producing ▁a ▁paper ▁chart . ▁Un mark ed ▁charts ▁were ▁not ▁class ified , ▁but ▁those ▁with ▁annotations ▁were ▁class ified ▁as ▁secret . ▁A ▁bel ly - mount ed ▁AN / AP S - 2 0 ▁surface - search ▁rad ar ▁enabled ▁detection ▁of ▁sur fac ed ▁and ▁sn ork eling ▁sub mar ines ▁at ▁considerable ▁distances . ▁ ▁As ▁the ▁P - 2 ▁was ▁replaced ▁in ▁the ▁US ▁Navy ▁by ▁the ▁P - 3 A ▁Or ion ▁in ▁active ▁Fle et ▁squad rons ▁in ▁the ▁early ▁and ▁mid - 1 9 6 0 s , ▁the ▁P - 2 ▁continued ▁to ▁remain ▁oper ational ▁in ▁the ▁Naval ▁Air ▁Reserve ▁through ▁the ▁mid - 1 9 7 0 s , ▁primarily ▁in ▁its ▁SP - 2 H ▁version . ▁As ▁active ▁Fle et ▁squad rons ▁transition ed ▁to ▁the ▁P - 3 B ▁and ▁P - 3 C ▁in ▁the ▁mid - ▁and ▁late - 1 9 6 0 s ▁and ▁early ▁ 1 9 7 0 s , ▁the ▁Naval ▁Air ▁Reserve ▁P - 2 s ▁were ▁eventually ▁replaced ▁by ▁P - 3 As ▁and ▁P - 3 B s ▁and ▁the ▁P - 2 ▁ex ited ▁active ▁U . S . ▁naval ▁service . ▁V P - 2 3 ▁was ▁the