 Shortly before dawn on 10 April , the five destroyers of the British 2nd Destroyer Flotilla surprised the German ships in Narvik harbor . They torpedoed two destroyers and badly damaged the other three while suffering only minor damage themselves . As they were beginning to withdraw they encountered the three destroyers of the German 4th Flotilla which had been alerted when the British began their attack . The Germans opened fire first , but the gunnery for both sides was not effective due to the mist and the smoke screen laid by the British as they retreated down the Ofotfjord . The German ships had to turn away to avoid a salvo of three torpedoes fired by one of the destroyers in Narvik . Giese and Koellner were very low on fuel and all three were running low on ammunition , so Commander Bey decided not to continue the pursuit of the British ships since they were being engaged by the last two destroyers of Group 1 . 
