Exactly. This is laughable. I do not understand why during a sport diving training, students are not pushed, with the right supervision, to go into a small one minute deco obligation. Just in order to find out how their computor would react and what indications are to be followed. This is much better than to have the same experience, on your own and have to try to figure out what your computor is telling you.
Its pretty easy to teach that lesson without taking the risk of heavily saturating oneself.
Here's how I approach it:
1. If using a GF driven computer (i.e. Shearwater etc), pre-plan a conservative NDL for the dive. Track that NDL and surface well within it. Set GF to something ludicrous (like 10/30) so that significant staged deco is reached very quickly. I use this method for running 'simulated staged deco' training dives with tech students, whilst also keeping dive parameters very conservative during the learning (and mistake making) phase of training.
2. Conduct a dive using an appropriate EANx mix, but leave the computer set for air. Plan the EANx NDL and dive within it. The computer tracks as per air, so you can enter lite deco safe in the knowledge you're well insulated from DCS risk. I use this to teach recreational divers how their computers will respond/display to emergency deco situations.
For recreational divers, my message is simple:
DCS risk is a grey area, not black and white. Modern decompression algorithms and no-stop limits keep divers reasonably safe from risk, even accounting for other predisposing factors.
As you approach no-stop limits, there is less insulation against those risks.. so one has to be much more mindful of contributory risk factors like ascent speeds, safety stops, proper hydration, exertion, thermal protection, body composition, cardio-vascular fitness and personal physiological issues.
Exceeding no-stop limits makes dives less forgiving. Smaller predisposing or dive management factors now have a more immediate and profound impact. The medical consequences of those factors occuring become more severe.
As those no-stop limits are further exceeded, the DCS risk changes from reasonable to unreasonable. From unlikely to likely. From non-damaging, to injurious, to potentially fatal.
Those risks cannot be eliminated, but they can be mitigated. Risk mitigation is possible through appropriate and specific training and equipment... all of which is readily available across the globe.
To speak about small deco obligation as a "mortal sin" is, for me, stupid.
I don't recall seeing what you just quoted anywhere in this, or another, thread.
Who are you quoting exactly?!?
NDL is a "statistical evaluation" of a risk...
It is nonetheless representative of a
real risk of injury. DCS isn't some hypothetical or fictional malady, nor is it restricted only to 'extreme' deco divers.
Did you ever get bent, or be on a dive with someone how got bent?
Real experience with DCS tends to eliminate any gung-ho bravado or delusions of invincibility. It tends to sober people towards a conservative approach to diving...especially when you become cognizant of the small factors that can make the difference between healthy and harmful results.
Even avoiding 'scare stories' about paralysis and death, the results of DCS injury and treatment can have profound long-term consequences for the diver.
Rehabilitation from DCS injury, even if treated, can be prolonged and life impacting. Even with a full recovery (
no nerve or tissue damage), it's likely that the victim might be restricted from further diving for some time.
So... when pushing that 'grey area' is the benefit of a pathetic few extra minutes even worth the risk of being medically prohibited from further diving for months afterwards? Or missing a flight home from vacation? Or a significant medical bill that may not be fully covered by your insurance? Or the trauma and upset you cause to friends, family and fellow divers by subjecting yourself to emergency medical care?
Are those few extra minutes
really worth the risk of pushing yourself further into a grey zone where DCS likelihood and increased severity of injury becomes more significant?
The reason technical diving training exists is to
mitigate those increased risks. It provides a significantly higher standard of dedicated training, along with a proven (
accident analysis driven) equipment and techniques blueprint for preserving a high degree of safety and risk insulation. In short, it balances risk appropriately.
I really don't understand the lemming-like obsession to push one's tolerances into potentially injurious and unforgiving dive parameters. To push dives up to, or beyond no-stop limits.... to show
scorn for conservatism... For what? A few pathetic extra minutes at depth?
If someone was that desperate and carefree for a few extra minutes underwater, then they'd probably benefit from diving more frequently... rather than diving more aggressively.
Or if they truly needed the capacity to dive deeper or longer than reasonable no-stop limits permit, then they can take advantage of the readily available training and equipment that empowers extended diving with a high degree of risk mitigation.