The Haiqing class are a submarine chaser

Submarine chaser

A submarine chaser is a small and fast naval vessel specially intended for anti-submarine warfare. Although similar vessels were designed and used by many nations, this designation was most famously used by ships built by the United States of America...

/patrol boat

Patrol boat

A patrol boat is a relatively small naval vessel generally designed for coastal defense duties.There have been many designs for patrol boats. They may be operated by a nation's navy, coast guard, or police force, and may be intended for marine and/or estuarine or river environments...

 of the People's Liberation Army Navy

People's Liberation Army Navy

The People's Liberation Army Navy is the naval branch of the People's Liberation Army , the military of the People's Republic of China. Until the early 1990s, the navy performed a subordinate role to the PLA Land Forces. Since then, it has undergone rapid modernisation...

. There is some disagreement over the type designation of this class, some sources claim it is Type 037I, while others claim it is Type 037IS.

Unlike western navies, the PLAN does not have dedicated patrol boats in its inventory, instead, a variety of naval vessels ranged from minesweepers to fast attack craft are deployed for patrol duties. The Haiqing class is one of such Chinese designs and it is a cross between gunboat

Gunboat

A gunboat is a naval watercraft designed for the express purpose of carrying one or more guns to bombard coastal targets, as opposed to those military craft designed for naval warfare, or for ferrying troops or supplies.-History:...

s and the submarine chaser, based on Type 037 (Hainan class)

Type 037 class submarine chaser

The Type 037 class submarine chaser, also known as the Hainan class, is a class of submarine chaser of the People's Republic of China's People's Liberation Army Navy, designed by China to replace the Soviet S.O.-1 class submarine chaser...

. These boats were first built by the Qiuxin Shipyard of Shanghai

Shanghai

Shanghai is the largest city by population in China and the largest city proper in the world. It is one of the four province-level municipalities in the People's Republic of China, with a total population of over 23 million as of 2010...

, and later by Huangpu Shipyard.

The vessel is armed with two 6-tubed anti-submarine mortar launchers. Early variant Haiqing class are fitted with two manually operated twin-barrel 37 mm guns, but they are replaced by two automatic 37 mm guns on the later variants. They also have various other mounted heavy machine guns for patrol duty. These weapons focus on a general-purpose patrol boat, with only a limited anti-submarine capability.