For the last two decades China has been installing more and more 55mm DP-65 remotely controlled anti-swimmer grenade launching systems on its ships and in some coastal bases. This is because more Chinese ships are visiting foreign ports and need that kind of protection. The DP-65 is also seen on the platforms China is building on or near disputed rocks, reefs, and uninhabited islands in the South China Sea.
The DP-65 uses a special kind of sonar used to detect swimmers nearby. The six barrel DP-65 is designed to defeat underwater attackers using scuba gear to approach and plant bombs or simply seek out information. The 55mm grenades are similar to those found on RPGs but have a flare at the end so that sailors on shore can see where it lands and know where the swimmer might be. The 55mm grenade has a fuze which sets off the warhead when the grenade reaches a preset depth. When the grenade explodes it will kill or injure any swimmer within 16 meters.