The operational order for the attack on "Tirpitz" was issued by No. 5 Group on 24 October. It specified that the battleship was to be attacked by 36 Lancasters, Nos. 9 and 617 Squadrons each contributing 18. Another Lancaster from No. 463 Squadron RAAF's film unit would also take part but not carry any bombs. As the "Johnnie Walker" mines had failed during Operation Paravane, only Tallboy bombs were to be used, each bomber carrying one of the weapons. These bombs were the largest in service with the RAF, and were capable of penetrating heavily armoured targets. The two squadrons were to remain at their home bases until it was judged that weather conditions over Tromsø were likely to be suitable. They would then be bombed up, and fly to RAF Kinloss, RAF Lossiemouth and RAF Milltown in northern Scotland. The operational order stated that the attack was required as "it appears likely that the Germans may attempt to get the battleship back to a base in Germany, where the necessary repairs and refit can be carried out".