 The British strike force was detected by German radar stations when it reached a point 43 miles ( 69 km ) from Kaafjord at 02 : 00 . It took four minutes to pass a warning to Tirpitz ; her protective smoke generators were in action by 02 : 13 and quickly covered the vessel in an artificial cloud . The battleship and anti @-@ aircraft batteries located on the shore began firing a barrage towards the British aircraft at 02 : 19 . German forces also began jamming the British aircraft 's radios once they came within 10 miles ( 16 km ) of the Norwegian coastline . The smokescreen frustrated the British attack , as the crews of only two of the Barracudas and a pair of fighters managed to spot Tirpitz during the raid . 
