A fishing boat owner in Tianjin whose sinking vessel with five people on board was saved by police, has sent the rescuers a banner reading "diligent trouble shooters" to thank them for their efforts.

Police in Binhai, Tianjin, saved a sinking wooden fishing boat, which became surrounded and trapped by several iron ships in the lower reaches of Haihe River on Jan 2, local website enorth.com reported.

The owner of the boat, surnamed Yang, sent the police a banner in recognition of their courageous efforts.

Police said seven iron ships were pushed downstream by gushing water after water gates were lifted at night on Jan 2.

The boats soon surrounded Yang's wooden fishing boat, which started to sink. Although police rushed to the scene as soon as Yang called for help, they were unable to locate the boats due to poor visibility.

The five people trapped on board were only saved when the police informed the responsible department to close the floodgates.