Complex sentence: After the battle, the frigate HMS "Euryalus" took the "Royal Sovereign" in tow and returned her safely to Gibraltar, although the "Santa Ana" was lost in the storm which followed the battle.
Split into simpler sentences: After the battle, the frigate HMS "Euryalus" took the "Royal Sovereign" in tow and returned her safely to Gibraltar. The "Santa Ana" was lost in the storm that followed the battle.