Complex sentence: After the North Koreans began taking hits, they attempted to flee the engagement, but were chased by the "Bak Du San" in a running battle that ended with the steamer being sunk near Tsushima Island, with heavy loss of life.
Split into simpler sentences: After the North Koreans began taking hits, they attempted to flee the engagement. In a running battle the "Bak Du San" chased the enemy steamer down and it sank near Tsushima Island with heavy loss of life.