Pakistan’s Hangor Submarine Push Raises Strategic Concerns in Bay of Bengal. Pakistan’s induction of the Chinese-built Hangor-class submarines is increasingly being viewed as a significant shift in the regional naval balance, especially with reports indicating ambitions to expand operations into the Bay of Bengal. The submarines—based on China’s Type 039A design—are equipped with air-independent propulsion (AIP), allowing them to stay submerged longer and operate with greater stealth.Â