Objectives  In order to increase the range and flow rate of the water cannon system, drag reduction additive was introduced.

  Methods  Firstly, the experimental results showed that the typical drag reduction additive was also effective for seawater system. Secondly, the hydraulic model of the water cannon system was established. Finally, an automatic two-stage drag reducer injection system with slotted sieve holes was put forward. During the operation of the water cannon system, the mixing and injection of the drag reducer was carried out alternately, and the plunger pump was used to add the drag reducer with the corresponding flow.

  Results  The simulation studies show that the additives can increase the range of the water cannon by about 20% and increase the flow rate by about 8% during 15 minutes utility enhancement period.

  Conclusions  Turbulent drag reduction by surfactant additives can improve the range and flow rate of water cannon for a short time with great application potential for the law enforcement vessel.