thrust by finning, and all lift must be from buoyancy. A further problem is that if the divers are separated, the rescuer will be considerably positively buoyant, and the victim may well be negative, and sink away before the situation can be corrected. If there is a surface marker buoy available with sufficient buoyancy, the rescuer can clip the casualty to the reel and use the reel to hoist the casualty to the surface. In this case the casualty will not sink back down if released for any reason. Not all diving reels are suitable for this application. The reel needs a ratchet and a winding knob with a good grip and sufficient leverage. Some reels seize up when wound in under too much tension. If there is a swell running, the line tension will decrease after each wave passes, at which time winding in will be easier. If the casualty is not breathing, an urgent ascent directly to the surface is needed so that resuscitation can take place there. In this situation and if the rescuer needs to do decompression stops, the rescuer has a dilemma; take the casualty to the surface and increase the risk or severity of decompression sickness, including irreversible injuries or death, or do the stops and risk leaving the casualty to die by asphyxiation or drowning. In these circumstances the value of a surface backup team becomes obvious, as a message or pre-arranged signal to the surface can bring a standby diver down to take over the recovery of the casualty while the initial rescuer attends to his own safety, or the rescuer can send the casualty to the surface by buoyancy, while remaining at the required depth for decompression. If the rescuer chooses to stop for required decompression, the non-breathing casualty may be made positively buoyant and allowed to surface, where there is at least a possibility of assistance from bystanders or surface team members. This strategy has been successfully used in at least one incident. Active management of the casualty's airway during the ascent is necessary only as far as avoiding or correcting any position that tends to close the airway, such as extreme flexion of the neck. Expanding gases will generally pass passively out of the airway during rescue from depth, and pulmonary barotrauma is rare. A gradual and natural outflow of expanding air during the ascent may help prevent aspiration