Type 639 auxiliary ship

The Type 639 (NATO reporting name: Kanhai) is a class of Chinese People's Liberation Army Navy (PLAN) auxiliary ship. The Type 639 is an ocean surveillance ship using a small-waterplane-area twin hull; it is equipped with a tactical towed array sonar for observing submarines. The Type 639A is a hydrographic survey variant which may retain some submarine surveillance capability; existing or new ships may have been converted.