Haixiu 121-class tug

Haixiu 121 class tug is a class of little known naval auxiliary ship currently in service with the People's Liberation Army Navy (PLAN). The name of this class is after the first unit commissioned, with the exact type still remains unknown, and only a single unit of this class have been confirmed in active service as of mid-2010s.

The designation of Haixiu 121 class series tug is unique in that it is different than the usual Chinese naming convention for ships in the military service. Ordinarily, auxiliary ships in PLAN service are designated by a combination of two Chinese characters followed by three-digit number. The first Chinese character denotes which fleet the ship is service with, with East (Dong, 东) for East Sea Fleet, North (Bei, 北) for North Sea Fleet, and South (Nan, 南) for South Sea Fleet. The second Chinese character is designated by the mission the ship performs, and it is usually Tuo (拖), meaning tug in Chinese, for ships that are classified as tugboats. Haixiu 121 is a tug, but instead, the first Chinese charater is Hai (海), meaning ocean in Chinese, while the second character is Xiu (修), meaning repair, and such designation is for repair ships. However, this boat has not been observed being used as a repair ship, but instead, used as a tug. Furthermore, no obvious repair equipment can be observed onboard the boat. The pennant numbers may have changed due to the change of Chinese naval ships naming convention.