More conservative/"alternative" diving profiles?

[A_Buhlmann]

Most are no longer using the deep stop theory as it adds to ongassing. The only way to reduce fatigue is to slow your ascent. After a safety stop, take at least another minute or two to ascend from fifteen feet.

Thanks! NAUI recommends no more than 9m( ~30ft) per minute, while PADI recommends a maximum of 18m( ~60ft) per minute. I think I am going to follow NAUI's rule, even tough being a PADI certified diver... Never can add too much conservadorism in the diving world

 

[A_Buhlmann]

Which version of the NOAA Dive Manual, and which section/pages?

The very beginning, Chapter 1 or 2. Don't have the book with me right now... I have the 4th edition

 

[Ashes]

NAUI recommends no more than 9m( ~30ft) per minute, while PADI recommends a maximum of 18m( ~60ft) per minute. I think I am going to follow NAUI's rule, even tough being a PADI certified diver... Never can add too much conservadorism in the diving world

Be careful with that assumption, staying deep for longer is not necessary more conservative.
Going up too fast or too slow can be bad.

You need to do the assent rate that is used in the decompression tables for that set of tables to be useful.

Luckily dive computers can calculate your actual accent rate and recalculate decompression on the fly.


My point is; don't assume adding more time underwater or going slower is more conservative.

 

[Divectionist]

Thanks! NAUI recommends no more than 9m( ~30ft) per minute, while PADI recommends a maximum of 18m( ~60ft) per minute. I think I am going to follow NAUI's rule, even tough being a PADI certified diver... Never can add too much conservadorism in the diving world

Well yes, which bunch certified you means absolutely nothing. You have to make up your own mind on the subject, and it is not one that has all the answers figured out.

10m/min is a good rule for me from max depth to nearing the safety stop depth, however, from there to the surface I take it much slower due to the pressure differential.

I am also diving a conservative 50/75 gradient factor, as well as Nitrox. This combination, together with a relaxed ascent, should do pretty well. Otherwise dive hydrated, have some dark chocolate, and stay fit

 

[lowwall]

There has been very little research on deep stops, or more accurately for this type of stop, intermediate stops.

What has been done seems to suggest that true deep stops (stops at deeper than half depth) are not helpful. But an intermediate may well be. See https://www.researchgate.net/publication/5601761_Effect_of_varying_deep_stop_times_and_shallow_stop_times_on_precordial_bubbles_after_dives_to_25_msw_82_fsw

Dives with 2 1/2 min deep stops yielded the lowest PDDB scores--shorter or longer deep stops were less effective in reducing PDDB. The results confirm that a deep stop of 1 min is too short--it produced the highest PDDB scores of all the dives. We also evaluated shallow stop times of 5, 4, 3, 2 and 1 min while keeping a fixed time of 2.5 min for the deep stop; increased times up to 10 min at the shallow stop did not further reduce PDDB. While our findings cannot be extrapolated beyond these dive profiles without further study, we recommend a deep stop of at least 2 1/2 mins at 15 msw (50 fsw) in addition to the customary 6 msw (20 fsw) for 3-5 mins for 25 meter dives of 20 to 25 minutes to reduce PDDB.

 

[MargaritaMike]

Well yes, which bunch certified you means absolutely nothing. You have to make up your own mind on the subject, and it is not one that has all the answers figured out.

10m/min is a good rule for me from max depth to nearing the safety stop depth, however, from there to the surface I take it much slower due to the pressure differential.

I am also diving a conservative 50/75 gradient factor, as well as Nitrox. This combination, together with a relaxed ascent, should do pretty well. Otherwise dive hydrated, have some dark chocolate, and stay fit

Three great points. 1) Use the information available to you and make a decision on how you want to apply that information. It may not always be what you were taught at certification time. One should never stop gathering information about diving safely.

2) I like these rates. Ascend at 10m/min or less to 15-20 feet. After that I use 10ft/min to the surface. I try to plan that extra 2 minutes into my air consumption. I have seen many people (as well as myself in earlier times) get to 15ft., do their safety stop, and then pop to the surface. I think that is not good.

3) Dive a conservative GF w/ Nitrox AND eat lots of dark chocolate (I do try to stay hydrated, but fit left me somewhere between my 6th and 7th back surgery).

Cheers - M²

 

[Ghost95]

Deep stops never made sense to me because it seemed like you would continue on gassing certain tissues even though you would be off gassing others and I don't know enough math to figure it out. It seems like if you did a deep stop at half your max depth you might need stop at half your deep stop depth too to off gas the extra nitrogen you built up. Who knows but that is getting into stage deco type stuff and beyond my personal recreational threshold.
Me, personally, I've made the decision not to do deep stops and I disable that option on my computer. Instead I slow my accent rate and, after reading more on the subject, will slow my accent from 15' to the surface.

Remember, it's not how deep you go or how long you stay, it's how fast you come up.

Within reason of course.

Safe Diving.

 

[A_Buhlmann]

Well yes, which bunch certified you means absolutely nothing. You have to make up your own mind on the subject, and it is not one that has all the answers figured out.

10m/min is a good rule for me from max depth to nearing the safety stop depth, however, from there to the surface I take it much slower due to the pressure differential.

I am also diving a conservative 50/75 gradient factor, as well as Nitrox. This combination, together with a relaxed ascent, should do pretty well. Otherwise dive hydrated, have some dark chocolate, and stay fit

Very good point indeed! what is the deal with dark chocolate? I love it! I guess one more reason to have it around

 

[A_Buhlmann]

There has been very little research on deep stops, or more accurately for this type of stop, intermediate stops.

What has been done seems to suggest that true deep stops (stops at deeper than half depth) are not helpful. But an intermediate may well be. See https://www.researchgate.net/publication/5601761_Effect_of_varying_deep_stop_times_and_shallow_stop_times_on_precordial_bubbles_after_dives_to_25_msw_82_fsw

Dives with 2 1/2 min deep stops yielded the lowest PDDB scores--shorter or longer deep stops were less effective in reducing PDDB. The results confirm that a deep stop of 1 min is too short--it produced the highest PDDB scores of all the dives. We also evaluated shallow stop times of 5, 4, 3, 2 and 1 min while keeping a fixed time of 2.5 min for the deep stop; increased times up to 10 min at the shallow stop did not further reduce PDDB. While our findings cannot be extrapolated beyond these dive profiles without further study, we recommend a deep stop of at least 2 1/2 mins at 15 msw (50 fsw) in addition to the customary 6 msw (20 fsw) for 3-5 mins for 25 meter dives of 20 to 25 minutes to reduce PDDB.

The study is about "Pyle stops" correct? This is the first one with a positive/conclusive outcome! A lot were inconclusive or borderline statistically significant... If you have any others I would appreciate it

 

[Divectionist]

Very good point indeed! what is the deal with dark chocolate? I love it! I guess one more reason to have it around

Linked to reducing endothelial dysfunction post-dive when ingested pre-dive. I guess it is one of those rare 'conveniently good news' things - although I trust it to be sufficiently minor.
Here is a study based on 30g of 86% chocolate taken 90min pre-dive: The effect of pre-dive ingestion of dark chocolate on endothelial function after a scuba dive. - PubMed - NCBI

Other things you may want to do:
- aerobic exercise
- sauna
- getting on those body vibration machines
- resting and hydrating properly
- making sure you do not have dietary deficiencies
- stay warm during and between dives to allow for efficient off-gassing
- ...