it was F/L Bruce Buckham.
he was flying the only non 9 or 617 Sqdn Lancaster on the raid.
He flew a camera equiped Lancaster of 463 Squadron RAAF from waddington.
These are his words.
"The first 2 were near misses and then pow; this was followed by 2 more in as many seconds, suddenly there was a tremendous explosion on board . The Tirpitz appeared to heave herself out of the water. carried away by this turn of events , and the suddenness of it all, we had descended to 200Ft cameras had been whirring at the task of collecting photographic evidence of the action.
we flew over it, around it and all about it, and still it sat there with dignity under a huge mushroom of smoke which plumed up a few thousand feet in the air. There were fires and more explosions on board, a huge gaping hole existed on the port side where a section had been blown out. We had been flying close around Tirpitz for 30 minutes or so and decided to call it a day so we headed out towards the mouth of the fjord. Just then the rear gunner, Eric Gierch called out "i think she's truning over" i turned back to port to have a look, and sure enough she was, so back we went again. this time we flew in at 50Ft and watched with baited breath as Tirpitz heeled over to port, ever so slowly, and gracefully."
I wholeheartedly agree that if Dennis was responsible for turning her over then he should get the credit.
But there is no evidence that this is the case.
this is a plot of the postions of bombs dropped established from photographs.

full credit to John Asmussen for the use of his fine artwork above from his website http://www.bismarck-class.dk/tirpitz/hi ... chism.html" onclick="window.open(this.href);return false;
only 2 bombs are known to have actually been direct hits on The Tirpitz.
The very first bomb dropped was by Willie Tate and is believed to be the one that penetrated the magazine causing the major explosion that ripped her side out causing the flooding.
One near miss is reported to have " sucked her sideways" but not roll her over.
The roll over was caused by flooding not by the blast of a Tallboy.
if there is any evidence that a tallboy rolled her over then i haven't seen it yet and will be happy to be corrected.
Non of the pilots or survivors have ever claimed their bomb rolled her over to my limited knowledge and the evidence does not support that as a hypothesis.
Incidentally it was a 9 sqdn bomb that disabled the Tirpitz in an earlier raid. It was the only hit of the raid and the bonb destroyed the engine room.
She was towed to Tromso to act as a static gun ship as the Germans expected an invasion of Norway and she was to be part of the defence and was never going to sail under own steam again.
so you could say that 9 sqdn put her out of the war as there was not going to be an invasion of Norway but we didn't know the extent of the damage so had to go back and do it again.
regards
Geoff