"I knew I would have to go," he said.
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The young lieutenant became an observer and navigator in a three-man crew flying Fairey Barracudas from aircraft carriers in the North Sea and the Arctic Ocean.
"I had five years of war and saw a lot of pain," he said.
His crew dive-bombed German battleship Tirpitz in a Norwegian fjord.
"I did four attacks on the Tirpitz," he said. "We took off in the carriers and flew very low over the water so the German radar wouldn't pick us up. We would dive almost vertical."
But the bombs they carried weren't big enough to pierce the ship's deck, Densem said.
"The Tirpitz was a big ship and a very strong ship. But we managed to upset her steering and stop her from getting out of the fjords."
Densem said the Royal Air Force eventually sank the ship using 12,000-pound Tallboy bombs.
Densem claims he made it out of the war having crashed a plane only once, surviving the time his aircraft went down in a forest at a training establishment HMS Goshawk in Trinidad.
"I finished up under the petrol tank with my leg all twisted," he said.
One of the bones in his leg dislocated out of its socket, which he said still caused him pain today.
He pointed to an old photo of him standing among men he served with, his leg visibly bent.
"It was a bit of a mess."