Country: German Empire.
Class, [Type]: SM, [UB I].

Builder: Germaniawerft, Kiel, German Empire.
Laid down date: 4 December 1914.
Launch date: March 1915.
Commission date: 23 April 1915.
Decommission date: 25 May 1916.

Displacement ( tons ): 127 surfaced, 142 submerged.
Dimensions ( metres ): 28 x 3,2 x 3.
Main machinery: 1 x Daimler diesel engine, ( 60 hp ), 1 x Siemens-Schuckert electric motor ( 120 hp ).
Range ( miles ): 1650 at 5 knots surfaced, 45 at 4 knots submerged.
Speed ( knots ): 6,5 surfaced, 5,5 submerged.
Test depth ( metres ): 50.
Complement: 14.

Guns: 1 x 1 8mm machine gun.
Torpedoes: 2 x 1 450mm torpedo tubes ( bow ), ( 2 torpedoes ).
Comment: sold to Bulgaria 25 May 1916. She was renamed Podvodnik N 18.