at action stations; the main guns and port torpedo launcher were trained on Kormoran, and her Walrus scout plane had been readied for launch, prompting Detmers to prepare to engage Sydney, but her guns were unmanned, and personnel were standing on the upper deck. During her manoeuvre, Sydney appeared to signal "IK" (the short-form for "You should prepare for a cyclone, hurricane, or typhoon"), which Kormoran did not respond to, as from their perspective, such a signal did not make sense. The Germans were unaware that the letters were the interior of the real Straat Malakkas secret Allied-assigned callsign, "IIKP": to verify her identity, the ship had to signal back the outer letters. The aircraft was shut down by 17:25, and the catapult swung into the storage position; the two ships were too close for a safe launch. At around 17:30, after the raider had failed to reply for 15 minutes, Sydney signalled by light "Show your secret sign". Action In response to the cruiser's signal, Detmers ordered that Kormorans disguise be dropped, for the Dutch flag to be replaced by the Kriegsmarine ensign, and for the guns and torpedoes to open fire. Accounts disagree on which ship fired first but agree that both opened fire almost simultaneously. The first shots from Sydney, a full, eight-shell salvo from the main guns, were reported in most accounts to have passed over Kormoran. However, some of the Germans said that shells punched through the funnel and the wireless office at bridge level without exploding and hit the water on the far side of the raider. One analysis claims that this was either a warning shot just over the superstructure or an attempt to destroy the raider's bridge as a prelude to capture. With Kormorans opening salvo (which consisted of two shells instead of four because the raider's two centreline guns were slower to decamouflage), the gunnery officer attempted to bracket the cruiser's bridge but failed to hit it, with the shells striking other parts of the ship or missing completely. Two torpedoes from Kormorans starboard above-water tubes were launched simultaneously with the raider's attack, and the close proximity of the target allowed the use of the anti-aircraft and close defence guns to rake Sydneys flank, thus preventing the use of the cruiser's secondary weapons. Subsequent salvoes from the raider were more accurate. The second, three-shell salvo destroyed Sydneys bridge and damaged her