Complex sentence: On 18 February 1910, during exercises in the Gulf of Jouan, a torpedo was accidentally launched from her sistership "Patrie", which struck the "République", damaging her hull.
Split into simpler sentences: On 18 February 1910, during exercises in the Gulf of Jouan, a torpedo was accidentally launched from her sistership "Patrie". The torpedo struck the "République", damaging her hull.