AAMOF I have just finished reading Paul Brickhill's "Dam Busters" (again) and the last 3 chapters are full of the accuracy of 617's latter day attacks on Tirpitz, Bielefeld viaduct, Dortmund Ems canal, the Rocket sites, U-Boat pens and the German battleship Lutzow. 9 Sqdn accompanied 617 on several occasions, including two attacks on the Tirpitz but their contribution was not lauded the way that 617 was.
The attack on the Lutzow is amusing in the sense that bombs were seen to hit it several times but recce photos showed it was still at its moorings. What no-one knew was they HAD sunk it - the difference was that they made a massive hole in the bottom and it had sunk onto the sea bed! The third attack on the Tirpitz was not needed for a similar reason - but no-one knew that either!
The accuracy of 617's bombing was down to practice and the methods that Cheshire introduced. Other than direct hits with tallboys Barnes Wallis's preferred delivery was to land the bomb around the more difficult targets and cause an earthquake - as little as 30 yards, which was achieved most of the time. The Grand Slam was not used until early March 1945.
A great read, which I expect to do again!