one has to wonder why it was not re-attacked with a 'Tallboy' which would have been much more effective.
It was, by 9 Squadron on 15th October 1944 and they got at least 8 direct hits including one slap bang on the center of the dam. Though you can only see 6 craters on the air side and crest of the dam in the photo below, at least one exploded waterside and another water side Tallboy UXB'ed and had to be defused in the late 1950's. No it was no more effective as the Tallboy had a lighter charge to weight ratio than Upkeep and the dam design was much more resistant to shockwaves than the Möhne and Eder were.
The crews of Bomber command have the respect of all informed national opinion for their bravery and sacrifices.......... we'll all informed opinion excepting the very Govenment who sent them on this dangerous and necessary task and still show disrespect having since 1945 failed to issue a campaign medal.
The campaign medal issue is a lot more complicated than most people think. It wasn't that a medal wasn't offered...It was, it's that Harris wanted EVERYBODY in the Command, including the ground staff to get it and Churchill said NO.