Complex sentence: The Spanish ships return the fire with anger, but the accurate shots of the allied ships forced them to seek cover behind the Abtao island and continued the battle with elevation shots; they slowly retreat after two hours of battle and 1500 shots from both sides.
Split into simpler sentences: The Spanish ships return the fire with anger, but the accurate shots of the allied ships forced them to seek cover behind the Abtao island and continued the battle with elevation shots. Finally, the Spaniards slowly retreat after two hours of battle and 1500 shots from both sides.