[He] was a great talker, words tumbling from his lips at an amazing rate, and his gift for rhetoric was superbly demonstrated in his lecture presentation on the sinking of the Bismarck. Geoffrey had served in the Royal Navy Reserve on one of the ships that sent the German battleship to the bottom on 27 May 1941, so his graphic descriptions were wholly authentic.
Yet I remember him not so much for his oratory as for a remarkable piece of navigation that brought Carinthia safely to the Pier Head in Liverpool when the Mersey was cloaked completely in blinding black fog. We were anchored in the river waiting for the solid blanket to lift; even the ferry boats across the Mersey were unable to move. Suddenly Geoffrey's fine voice called: 'We're going in.' He talked our tugs to us over the VHF radio and, with visibility down to zero, took the huge 22,000-ton liner cleanly into the landing stage. Passengers, already resigned to another night at sea, cheered in relief and delight, and the crew, anxious to get home to loved ones, were equally elated. It was a magnificent achievement by the Captain, considering the quite elementary navigational aids of 1960 in comparison to today's sophistication.
Captain Arnott then explains how he believes Captain Marr accomplished this feat:
It's a matter of record that some Captains have a sixth sense in fog; they can 'see' things quite invisible to the eyes of ordinary humans, and have often made apparently inexplicable decisions which, within seconds, have saved ships and lives.
Perhaps it is either ouf of modesty that many captains do not wish to talk about it. Perhaps it is due to the fact they themselves cannot explain.
In any case, Captains generally won't discuss the matter, and that includes the normally prolific talker, Commodore Geoffrey Marr.
References: Captain Robert Harry Arnott, Captain of the Queen: The autobiography of the most famous sea captain of them all. (London: Quadrant Books, 1982), 125-126.