|This is a PBY from VP-63. VP-63 operated out of Port Lyautey in North Africa, patrolling the Straits of Gibralter to prevent German U-boats from entering the Mediteranean. Theirs were first planes to operate with MAD (Magnetic Anomaly Detection) gear and retro rockets (mounted under the wings). When a submarine was detected directly below, the retro rockets were fired backwards at a speed matching the plane's forward velocity. The result was that the bombs fell straight down, rather than forward.
Another photo of this plane can be found in PBY Catalina In Action, p34.
(Photo from the R.L.Lawson collection, courtesy of the Nat'l Museum of Naval Aviation)