Deep stops and ascents...

[Calvinandhobbs]

We were told a three minute stop at 15 feet is considered to be good practice.

 

[LiteHedded]

I bounce to the bottom and spend my entire dive doing safety stops.
the rest of you guys ARE GOING TO DIE!!!!!

 

[Charlie99]

I bounce to the bottom and spend my entire dive doing safety stops.

When possible, I prefer to do multilevel dives all the way back up to the surface too.

(Yeah, I know your post meant to poke fun at those that hang forever, but my serious point is that multilevel profiles do have lots of advantages. Unfortunately, normal tables don't do a good job of planning or tracking them, and multilevel dive planning isn't taught in OW courses.)

 

[AquaDuck]

vkalia wrote:
I am not saying deep stops are a bad idea, incidentally. Doesnt hurt to have a wee bit more safety. I do teach deep stops, but in AOW - not in OW. For 20m dives, it is not needed. For deep dives, it doesnt hurt to do it... and in some cases, it is indeed helpful.

I agree entirely. Both my wife and I dive with Suunto Mosquito and Stinger comp's and we make sure that our students stay either on eyeball level or slightly below one of us on ascents while the other (either her or I) bring up the bottom of the group; the ascent rates are *slower* than one bar on the mosquito or Stinger. Our OW students are taught to respect the 18m(60ft) limit and all other students the 30m(98ft) limit unless they have qualified as Deep Divers and shown us their deep dive speciality cert cards for dives between 30-40m(98ft-131ft).

We thoroughly discuss safety stops in our OW courses and promote a 18m/2min level off dive/stop for dives deeper than 30m(98ft) in our AOW courses. All students are taught to *always* make their safety stop at 5m/3min(16ft/3min) unless advised by their dive computers to do an *additional* stop within a certain depth ceiling/floor restraint, which usually means they violated some safe diving practice on the dive like ascending too fast, ignoring dive limit times etc, in which case we'd increase our standard stop time to 5m/5min to be on the safe side after they have completed their required computer depth/time window.

By the very nature of the definition, No Decompression Diving means that under normal circumstances a decompression stop is not required *if* the diver sticks to the time limits religiously on their tables and/or computer. A Safety Stop becomes a mandatory PADI standard as an added safety measure when times are exceeded or limits are being pushed (i.e. 3 pressure groups from your NDL on PADI tables). That having been said, doing a 5m/3min and a 18m/2min stop/level off for dives deeper than 30m has become our standard practice stops under all circumstances for all dives.

As for air consumption, we start our ascends if anyone in the dive group reaches 75bar(1100PSI) on dives deeper than 18m(60ft), and 50bar(725PSI) for shallower dives to allow us to do safe, slow ascents and then comfortably do our 5m/3min stop.

 

[ArcticDiver]

-First Deep Stop is 2ATA from deepest point. Sometimes this is the same as 1/2 measured depth from the surface; sometimes not. The key is to get enough difference in ATAs that I'm truly offgassing.
-Ascent rate is 30fpm below 20' and no more than 10 fpm above.
-If a multi-level dive the Ascent Rate and Required Stops can be worked into the profile.
-From 40' up there are pauses every 10' until the 3-5 minute stop at 15'-20' depending on sea state and local geology.

I was taught 30fpm ascent and 3-5 minute "Safety Stop". But to regard the Safety Stop as a mandatory Deco Stop because "All Diving Is Deco Diving". Then a "slow" ascent rate to the surface.

Deep Stops were added once I started recognized that diving is an art, not a science and I had better understand the underlying scientific principals.

 

[lowwall]

For typical recreational profiles, it doesnt make a snit of a difference whether you do deep stops or not - no matter how fashionable they may be. I find it a bit funny when I see loads of earnest - and well-meaning divers - doing a deep stop after a 24m doddle along the reef or whatever.

"It now appears that subclinical changes can occur without overt manifestations of decompression sickness. This is documented by the increasing frequency of cases of dysbaric osteonecrosis and hearing difficulties diagnosed in commercial divers. Sport scuba divers may be at risk for these other latent symptoms affecting the brain, spinal cord, eyes, and lungs." - Long-term Effects of Diving in "Medscape Orthopaedics & Sports Medicine eJournal"

It may not make a snit of difference if you are comparing relative DCS rates, but it makes a noticeable difference in post-dive fatigue. And I find it pretty hard to ignore the conclusion that the fatigue is indicative of something negative going on in the body, perhaps it is even an indicator of damage that may lead to the problems mentioned above.

 

[ArcticDiver]

Could you explain please? My understanding and experience doesn't support this statement. After I explain, please educate me.

Fatigue, to me, merely indicates that a person is fatigued, i.e. tired. So when I get to the end of my workout at the gym, I'm fatigued/tired. If, like I'm doing now, I'm doing unaccustomed exercise(working out at 5700' instead of my accustomed 435') I'm unusually fatigued/tired.

So, if I'm just fatigued/tired with no other clinical symptoms how is this an indicator of anything else other than I need to rest and nourish myself? One of the tenets of strength training is to work until the muscles won't respond any more(total fatigue) then rest and nourish so the body can build new and stronger muscle.

So ,if a person is fatigued after a dive doesn't it mean that the person is merely tired? After all don't most divers indulge in their sport infrequently? Therfore, their bodies and minds are unaccustomed to the physical stresses and the mental anxiety involved in diving? If so, fatigue/tiredness after diving is a normal result of the activity. They just need to rest and nourish before doing it again.

This is entirely separate from the commercial diver who does the job on a daily basis and therefore can be assumed to be mentally and physically accustomed to the stresses of that job. If that person becomes unusually fatigued that would be a clinical symptom worth investigating.

Oh yes, the key word in your quoted article is "may". The author has a theory that "may" be true. But while there is some evidence for this among commercial divers there is a paucity of similar evidence among recreational divers. Or, at least that I've been able to find.

.

 

[lamont]

Could you explain please? My understanding and experience doesn't support this statement. After I explain, please educate me.

Fatigue, to me, merely indicates that a person is fatigued, i.e. tired. So when I get to the end of my workout at the gym, I'm fatigued/tired. If, like I'm doing now, I'm doing unaccustomed exercise(working out at 5700' instead of my accustomed 435') I'm unusually fatigued/tired.

So, if I'm just fatigued/tired with no other clinical symptoms how is this an indicator of anything else other than I need to rest and nourish myself? One of the tenets of strength training is to work until the muscles won't respond any more(total fatigue) then rest and nourish so the body can build new and stronger muscle.

So ,if a person is fatigued after a dive doesn't it mean that the person is merely tired? After all don't most divers indulge in their sport infrequently? Therfore, their bodies and minds are unaccustomed to the physical stresses and the mental anxiety involved in diving? If so, fatigue/tiredness after diving is a normal result of the activity. They just need to rest and nourish before doing it again.

This is entirely separate from the commercial diver who does the job on a daily basis and therefore can be assumed to be mentally and physically accustomed to the stresses of that job. If that person becomes unusually fatigued that would be a clinical symptom worth investigating.

.

Different post dive outcomes:

1. got up at 6am for a dive, get home, nap: normal
2. got enough sleep, did a dive, get home, watch TV/DVD, read scubaboard, relax, stretch sore muscles: normal
3. got enough sleep, did a dive, nearly fall asleep on the drive home, fall asleep on the couch, fever chills and "stoned" feeling: not normal

#3 is what i call "post-dive fatigue"

and i dive 1-2 times a week at least and get at least 2 days of excersize (weights or swimming) a week, so diving usually doesn't knock me out completely.

i haven't had post-dive fatigue since i stopped diving air and started being religious about ascent rates.

 

[ArcticDiver]

Different post dive outcomes:

1. got up at 6am for a dive, get home, nap: normal
2. got enough sleep, did a dive, get home, watch TV/DVD, read scubaboard, relax, stretch sore muscles: normal
3. got enough sleep, did a dive, nearly fall asleep on the drive home, fall asleep on the couch, fever chills and "stoned" feeling: not normal

#3 is what i call "post-dive fatigue"

and i dive 1-2 times a week at least and get at least 2 days of excersize (weights or swimming) a week, so diving usually doesn't knock me out completely.

i haven't had post-dive fatigue since i stopped diving air and started being religious about ascent rates.

Your #3 also included clinical symptoms. Therefore, fatigue was just one of the sympoms you were exhibiting. To be accurate a person can not call all you were exhibiting by the name of only one symptom.

Your #1, by your description, was probably just post-dive fatigue since a nap took care of it and there were no other reported symptoms.

I absolutely agree about ascent rates. In my opinion the single most important thing a person can do is control their ascent rate. That is what our Diving Algorithms are all about, whether they are encapsulated in plastic sheeting or in an electronic device.

 

[lamont]

Your #3 also included clinical symptoms. Therefore, fatigue was just one of the sympoms you were exhibiting. To be accurate a person can not call all you were exhibiting by the name of only one symptom.

Maybe with the chills, but feeling "out of it/stoned" and "tired" are not really clinical symptoms. And I didn't have a fever over 99...

Your #1, by your description, was probably just post-dive fatigue since a nap took care of it and there were no other reported symptoms.

I should have mentioned that I normally don't get up at 6am though. Taking a nap after getting up at 6am is totally normal for me.

If I've had enough sleep and I still need to take a nap after diving, then that's a sign that something may be up.