Use of the continuous exhalation procedure from moderately (neutrally or relaxed) inflated lungs combines the advantages of lower risk of lung injury compared to either full or empty lungs with improved endurance due to more available oxygen. Keeping the DV in the mouth and attempting to breathe normally or slowly from it may provide additional breaths as the ambient pressure reduces, and helps ensure that the airways remain open. Ascent where the diver is propelled towards the surface by positive buoyancy. Generally recommended as a last resort, though a sufficiently skilled diver could control ascent rate by precise dumping from the BC and use this as a low energy alternative to a swimming ascent. In this case weights should not be ditched during the ascent. Inch Disco Ball Foil Balloons 5 pcs Retro Bachelorette Party Decorations Last Disco Decades Birthday Party Groovy 70s Bach to the 90s 80s Tethered-ascent – where the diver has unintentionally lost full control of buoyancy due to a loss of ballast weight, and controls ascent rate by use of a ratchet dive reel with the end of the reel line secured to the bottom. [2]

If the other diver has the gas available and is both willing and competent to provide it, the donor provides emergency gas and the two divers make an assisted emergency ascent while sharing gas using a single demand valve or octopus demand valve, or supplying the receiver from the donor's bailout set. policies of various certification agencies Toggle Training policies of various certification agencies subsection

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Emergency swimming ascent (ESA) is a free ascent where the diver propels him/herself to the surface by swimming at either negative or approximately neutral buoyancy. The standard PADI-trained technique is for the rescuer to approach the face-down unconscious diver (victim) from above and kneel with one knee either side of their diving cylinder. Then, with the victim's diving regulator held in place, [8] the tank is gripped firmly between the knees and the rescuer's buoyancy compensator is used to control a slow ascent to the surface. This method may not work with sidemount or twin cylinder sets, and puts both rescuer and victim at increased risk if the rescuer loses grip, as the victim will sink and the rescuer may make an excessively fast uncontrolled ascent. The SSAC trains open water free ascent from a maximum depth of 6–7m, initially using a shot line to control ascent rate, and considers the risk small and the benefit significant in view of their statistics which showed an incidence of roughly 16 free ascents per 10,000 dives.

On a type 2 bell, the divers' umbilicals are connected to the gas panel in the bell, and the procedure used should minimise the risk of the umbilical snagging during the ascent and forcing the diver to descend again to free it. If the diver excursion umbilical is not long enough to allow the diver to reach the surface, the standby diver will have to disconnect the bell diver's umbilical, and the rest of the ascent may be done on bailout, pneumo supply from the standby diver, or the standby diver can connect a replacement umbilical.When all else fails, the consequences of missing some decompression time are usually less severe than death by drowning. The technique involves simply ascending at a controlled pace, typically about 18 metres (60 feet) per minute, while exhaling slowly. As the diver ascends, the air in the lungs expands as surrounding water pressure decreases. Exhaling allows excess volume to escape from the lungs, and by exhaling at a suitable rate the diver can continue exhaling throughout the ascent and still have air in their lungs at the surface. If the diver fails to exhale during the ascent, lung over-expansion injury is likely to occur. If exhalation is limited to relaxing and allowing the expanding gas to escape without effort, there should not be a feeling of running out of breath, as the air inhaled at depth expands during the ascent and the lung volume should remain nearly constant.

Drowning is the most likely consequence of a failure to reach the surface during an independent emergency ascent, and is a significant risk even if the diver reaches the surface if he or she loses consciousness on the way.

mow, blow, and go

In the event that a free ascent is required, the lung volume should neither be too large nor too small, as both extremes increase the risk of injury. [3] A volume within the normal relaxed range should be suitable. Forceful exhalation before ascent increases the risk of lung injury, and reduces the available oxygen. Exhaling ascent [3] is an ascent where the diver continuously exhales at a controlled rate during the ascent. This may apply to an emergency swimming ascent/free ascent or a controlled emengency swimming ascent, and distinguishes it from a blow and go procedure. The only reference to emergency ascent training in the CMAS Diver Training Program (CMAS TC Version 9/2002) is in the 1-star course where Controlled buoyancy lift of victim to surface is specified under practical training of rescue skills. In the technique taught by BSAC and some other agencies, the rescuer faces the casualty and uses the casualty's buoyancy compensator to provide buoyancy for both divers as the rescuer makes a controlled ascent. If the casualty is not breathing, the ascent will be urgent. [8] If the two divers separate during the ascent, the use of the casualty's buoyancy is intended as a failsafe causing the casualty to continue to the surface where there is air and other rescuers can help. The rescuer will be negative at this point, but this is generally easily compensated by finning and corrected by inflation of the rescuer's BC.