NDL Stop Requirements / Rescue

[arthurmnev]

I just started studying for my rescue class and have a question to people that might have had experience rescue situation while in NDL

To set the baseline:
- a stop is a good idea
- a deep stop might be a good idea
- popping out like a champagne cork is never a good choice
- computers and charts have a good amount of safety built in

the question is: how likely is it to get DCS on ascent rates 0.5 - 1' / sec without a safety stop from ~80 or so feet while inside your NDL limits? Obviously nobody would do it without a good reason, but a person in trouble would likely qualify as one. Hence choices are:

- if possible, inflate their BCD and send them up
- Bring them up manually without a stop (obviously if he / she is not breathing, two (worst case) damaged divers is better than one dead)
- Bring them up with a stop (dont add another victim) and hope cold (relatively) water preserves them

Naturally, some of the decisions are based on how close the chamber is, but assuming a few hours away -- how measurable is the risk of going up fast, with no stop while inside of NDL?

 

[supergaijin]

I think you should wait until the instructor does his course and if there are any questions afterwards, either ask him/her or post again.

For me to answer ahead of your instructor would not be doing him/her any favours at this stage.

But it's good that you're already thinking

 

[Scott]

Yes deep stops might be a good idea (some agree, some disagree) and yes, a safety stop is a good idea, but neither are required if you're within the NDL of a dive. Your computer may limit your NDL on the next dive, but if it's a rescue, your day is over anyway.
Sixty feet per minute ascents were the norm many years ago and are still considered the maximum ascent rate when diving the DSAT (PADI) tables.

 

[ianr33]

Naturally, some of the decisions are based on how close the chamber is, but assuming a few hours away -- how measurable is the risk of going up fast, with no stop while inside of NDL?

The risk is very,very small.

If you are that concerned,bring the injured diver to the surface,inflate his BC,scream for help then drop back down to 20 feet for a long safety stop.

Inflating an unconscious divers BC and sending him to the surface is most likely going to kill him. I would only consider doing that if I had a LARGE deco obligation (> ~ 30 minutes)

 

[arthurmnev]

Yes deep stops might be a good idea (some agree, some disagree) and yes, a safety stop is a good idea, but neither are required if you're within the NDL of a dive. Your computer may limit your NDL on the next dive, but if it's a rescue, your day is over anyway.
Sixty feet per minute ascents were the norm many years ago and are still considered the maximum ascent rate when diving the DSAT (PADI) tables.

Thanks, that is exactly what I was looking for. If push comes to shove and I'm still within the NDL, "popping out" wont kill me

 

[Druid]

A safety stop is not a mandatory stop. If I was inside the NDL then I would bring the casualty straight to the surface without completing any stops. I would still ascend at 10m/min (30 ft/min).

 

[spectrum]

arthurmnev,

What you have described is a recreational dive with no overhead, hard or soft. You can go direct to the surface and 60 FPM used to be the norm. 30 FPM, Safety and Deep stops are enhancements that add margin above and beyond.

The bigger answer to get out of your class is how to evaluate handling the victim.

Pete

 

[scubadada]

Saving someone would negate either a deepstop or a safety stop, in fact, maximum ascent rate would be indicated. Specific circumstances may modify the situation.

 

[Fly swatter]

Be more concerned with getting them out of the water and onto a rescue platform. Taking the term VICTIM and turning them into a PATIENT is where it's going to make the difference. If your concern is about you coming to the surface without performing a safety stop, then you should have planned your dive better. Remember, that recreational diving is NDL diving, therefore, a safety stop is just a recommendation. We teach this, so that people are safer divers and are aware of what the safety stop is designed for.

 

[DBailey]

Hence choices are:

- if possible, inflate their BCD and send them up
- Bring them up manually without a stop (obviously if he / she is not breathing, two (worst case) damaged divers is better than one dead)
- Bring them up with a stop (dont add another victim) and hope cold (relatively) water preserves them

Naturally, some of the decisions are based on how close the chamber is, but assuming a few hours away -- how measurable is the risk of going up fast, with no stop while inside of NDL?

To me there is one choice:

Accompany the victim during the ascent at a safe rate. Do my best not to break contact with the victim. Do my best to maintain a safe ascent rate for the both of us. If the ascent starts to become out of control, let the victim ascend on his own (perhaps too quickly), and make sure my ascent stays safe. Do not go from rescuer to victim #2.

Completing a stop in an emergency situation for NDL diving is not even an option.