"Sécurité, sécurité, sécurité. All vessels, all vessels, all vessels, this is the Royal Navy. Live firing will commence at 0900 BST until 1100 BST in exercise area 73, Ailsa."
This generated some alarm but I knew that "Area 73 Ailsa" lay to the SW of Ailsa Craig and we were approaching the isle from the SE. However, a bank of sea fog rolled in, blotting out Ailsa Craig from view. We paddled steadily on but with a readiness to duck. All of a sudden, rounds of heavy automatic fire echoed out of the fog, Yikes!
HMS Mersey emerged from the mist to pass behind...
where she reappeared with a surfaced submarine alongside. We continued on our way undisturbed by further shell fire.