Complex sentence: The Type 037-class submarine chaser (NATO reporting name: Hainan-class), is a class of submarine chaser of the People's Liberation Army Navy Surface Force, designed by China to replace the Soviet S.O.-1 class submarine chaser.
Split into simpler sentences: The Type 037-class submarine chaser (NATO reporting name: Hainan-class), is a class of submarine chaser of the People's Liberation Army Navy. It was designed by China to replace the Soviet S.O.-1 class submarine chaser.