Complex sentence: The Russian shore batteries were capable of defending the city and repulsed the Turkish attack so Souchon chose to flee and when he reentered Turkish waters he met and engaged the Russian squadron and forced them to retreat after heavily damaging the lead ship.
Split into simpler sentences: The Russian shore batteries were capable of defending the city and repulsed the Ottoman attack, so Souchon chose to flee. When he reentered Turkish waters he met and engaged the Russian squadron and forced them to retreat after heavily damaging the lead ship.