based on block sketch dated May 1917 sent to the Dutch naval staff
Building ordered on 25 November 1910, laid down at the Kaiserliche Werft Danzig with yard number 13 on 20 October 1911, launched on 10 October 1912, commissioned on 6 July 1913 and handed over to England on 24 November 1918, and at Blyth broken up 1919-1920. Destroyed during the First World War 55 ships with a total gross tonnage of 101.389 tons included the British auxiliary cruiser Calgarian.
Double hulled project type 20 submarine wit as sister ships U 20, U 21 and U-22 which were the first German submarines fitted out with diesel engines. Displacement 650 (surfaced)-873 (submerged) tons and as dimensions 64,15 x 6,10 x 3,58 metres or 210.6 x 20.0 x 11.9 feet. Maximum diving depth 50 metres. Machinery consisted of 2-6 cylinder 850 hp MAN diesel engines and 2-600 hp AEG double Motordynamos allowing a speed of 15,4 (surfaced)-9,3 (submerged) knots. Crew numbered 35 men included 4 officers. Original armament 4-50cm torpedo tubes (bow 2, stern 2) or which she carried 9 torpedoes and 1-8,8cm gun until 1916. Since then 2-8,8cm guns and 1-10,cm gun.
