since when has it been in service?
10 May 1900
Petropavlovsk-class battleship
"Petropavlovsk" was the first of the sisters to enter service; she departed Kronstadt on 17 October 1899 and reached Port Arthur on 10 May 1900. 
describe the petropavlovsk-class battleship An upper belt of armor was necessary and the weight required was gained by shortening the waterline armor belt, which left the ships' ends protected only by the sloping armor deck. Other changes included the replacement of the barbettes with turrets of the same type as used in the battleship and the substitution of QF guns for the original guns. This last change saved enough weight to permit four more six-inch guns to be added what weapons does it carry? Four 40-caliber 12-inch guns mounted in twin-gun turrets fore do you know who built it? The director of the Naval Ministry, Vice Admiral
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Petropavlovsk-class battleship [SEP] Service
"Petropavlovsk" was the first of the sisters to enter service; she departed Kronstadt on 17 October 1899 and reached Port Arthur on 10 May 1900. Upon her arrival, she became flagship of the Pacific Squadron commander, Vice Admiral Nikolai Skrydlov. The ship supported international efforts to suppress the Boxer Rebellion in mid-1900. "Poltava" and "Sevastopol" departed for Port Arthur on 15 October 1900 and arrived on 12 and 13 April 1901 respectively. "Petropavlovsk" was the flagship of Vice Admiral Oskar Stark at the beginning of the Russo-Japanese War in February 1904. During the Battle of Port Arthur on the second day of the war, "Poltava" was hit twice in the aft hull, "Petropavlovsk" was hit three times in the bow and "Sevastopol" was hit once.