A visual signal is a signal sent when a ship is in distress and needs help. So that ships and planes going to rescue find the shipwreck. Visual signals include Rocket Parachute Flare Signal, Handheld Flame Signal, and Floating Smoke Signal.
The Rocket Parachute Flare Signal is launched by a rocket into the air at an altitude of not less than 300 m. At or near the apex of its trajectory, the rocket shoots a bright red flame with a parachute. The flame can burn uniformly for not less than 40 s, emit light intensity of not less than 30 000 cd, and its falling speed is not greater than 5 m/s, and will not burn the parachute or accessories when burning. This kind of signal is relatively easy to be detected by rescue boats.