An Ex-Sunderland man ( the late Dennis Moreau) told of participating in a joint RAF /RN exercise over the Atlantic in the 50's. During the subsequent debrief at Mountbatten a submarine commander stood up and announced that he has sunk an aeroplane.
Periscope photography was produced, showing Dennis's Sunderland sitting on the water with crew members perched up on the wing sunbathing and drinking coffee.
Thinking they had flown safely out of the exercise area being bored stiff, they had put down to while away couple of hours before their ETA back at Pembroke Dock.