HMS K26
 HMS K26 was the only modified K-class submarine of Britain's Royal Navy to be completed. One of six ordered she was laid down towards the end of the First World War but not completed until five years after its end.Six boats K23-K28 were ordered in June 1918 but the end of the war meant that only K26 was completed the remainder all being cancelled on 26 November 1918. Even so she was finished slowly.