March 19, 2022: China has apparently developed a new coastal submarine, mainly for the export market. The existence of these new subs was revealed February 8 ^th when a short video appeared on Chinese social media showing what appears to be a new class of coastal submarine moving south on the Yangtze River towards Shanghai, where there is a naval base used to prepare submarines, built in Wuhan, for sea trials. The new sub appeared to be coming from a shipyard in Wuhan that specializes in building submarines. The video later disappeared from Chinese Internet sites, usually indicating someone had posted something the government considered a state secret.

The earlier and similar S600 coastal submarine is not a secret and was first revealed, and offered for sale, in 2017. The S600 is a 600-ton sub that is 50 meters (155 feet) long and 4.6 meters (14.7 feet) wide. The sub is operated by a crew of fifteen. S600 has AIP (Air Independent Propulsion) which enables the sub to travel for 720 kilometers, or three or four days, underwater. Max range is 3,600 kilometers and max endurance is 20 days. There are four torpedo tubes which can carry torpedoes or naval mines. There is room for one reload of the torpedo tubes. Maximum depth is 200 meters (640 feet) and max submerged speed is 27 kilometers an hour and max surface speed is 16 kilometers an hour.

The new sub appears to be shorter than the S600, perhaps indicating that it is an improved S600 without the AIP. This makes the new sub more attractive to export customers who, like the Chinese Navy, have decided that AIP is overrated and often not worth the cost to install and maintain.

The S600 was developed by CSIC, a commercial firm that designs and builds most of China’s diesel-electric submarines. Like many Chinese defense firms, CSIC often develops new submarine designs with its own money and expects to make money on them via export sales. If the Chinese Navy places an order, that is a bonus. The S600, because of the AIP, costs about $200 million each. Delete the AIP and the purchase price goes down to $150 million, with lower operating costs as well.