Complex sentence: During the Battle of the Yellow Sea, after Admiral Wilgelm Vitgeft on the battleship had been killed in combat, Ukhtomsky transfered the fleet flag to his ship, the battleship and ordered the fleet to return to the safety of Port Arthur.
Split into simpler sentences: During the Battle of the Yellow Sea, after Admiral Wilgelm Vitgeft on the battleship had been killed in combat, command of the fleet fell to Ukhtomsky. Ukhtomsky ordered the fleet to return to the safety of Port Arthur.