Of the British H-class submarines launched on 10 June 1915 at the shipyard of Canadian Vickers&Co., Montreal, Canada, completed on 10 June and grounded on 19 January 1916 near the Dutch island Schiermonnikoog. The Netherlands were neutral during the First World War and she was interned. Finally England decided to sell her on 4 May 1917 to the Netherlands. With a displacement of 369/363 (long tons) (surfaced)-441 9434 long tons) (submerged) were her dimensions 45,80 x 4,67 metres or 150’3”x 15’4”. Speed 13 )surfaced)-10 (submerged ) knots. Her crew numbered 22 men and the armament consisted of 4-18”/45cm torpedo tubes and should carry 8 torpedoes with her.
She was next commissioned in the Royal Netherlands Navy as the Hr.Ms. O8 which upgraded her using the knowledge gained from the former German mine layer UC-8 which served now in the Royal Netherlands as the M-1. During the German invasion in May 1940 was she scuttled to prevent her capture.
The German forces however salvaged her and seeing that she was hardly damaged and commissioned her in the Kriegsmarine as the U-D1. In stead of Den Helder, Netherlands became Kiel, Germany her new station as a training ship for U-boat crews. However as she was already an old ship was she decommissioned on 23 November 1945 and two year later on 3 May at Kiel scuttled.
