Bars was ordered under the 1913 Programme for the Baltic Fleet, and was laid down at the Baltic shipyard in St. Petersburg. She was powered by diesel/electric propulsion, though a shortage of diesel engines meant the boats were equipped with a variety of machinery, as it became available. Armament, too, varied as to availability; Bars was armed with 1х75 mm and 1x 57 mm/50 gun,[1] Conway states about 2 x 63 mm guns.[2]
The design originally had external torpedoes as well as internal torpedo tubes; these were carried in drop-collars in recessed niches low in the hull. Trials with Bars showed these to be unsuitable and subsequent vessels had the niches and drop-collars moved to the upper deck; Bars was refitted to this pattern in 1916.
Bars was launched on 2 June 1915 and entered service the following month.[2]
Bars entered service with the Baltic Fleet on 12 July 1915. She undertook 14 war patrols in the Baltic, targeting German warships during the 1915 ice-free season, but with little success.[3]
In 1916 she was employed attacking German iron-ore shipments along the Swedish coast, though again with little success, due to the restrictions imposed by Swedish neutrality.[4]
On May 1917, Bars left port on her last patrol, and did not return. It is suggested by some that she was sunk in a depth-charge attack by German patrol boats on 28 May 1917,[2] though other sources suggest she was lost in a minefield off Norrköping.[5] The actual cause of her loss is unknown. In 1993, wreck of Bars was found and identified near Gotska Sandön at the depth 120 m.