25-17. On instruction from the boat commander or coxswain, the safety swimmer enters the water alongside the jumper to assist the jumper and to recover the parachute canopy and other equipment. If a jumper has gone underwater, the following action is taken: Red smoke is displayed to indicate an emergency and a message is transmitted to the command boat by radio. All other activities cease. (A red smoke grenade may be activated and dropped in an ammunition can bolted to a wood plate, or a smoke machine may be used.) The safety swimmer dives to recover the jumper and cuts themselves free of equipment, as required. The DZSO moves his or her boat to the scene and the medic or corpsman prepares to use the resuscitator and backboard.25-18. If using a rotary-winged aircraft, and the aircraft is alerted to assist in emergency recovery operations: When directed by the DZSO, the pilot stands by the location to provide medical evacuation by air, if necessary. After normal recovery operations, jumpers and equipment are unloaded at the assembly area. All boats are repositioned for the resumption of jump operations.