Deco dives/day or Deco+NDL/day... what are your guidelines?

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

Nasser

ScubaBoard Supporter
ScubaBoard Supporter
Messages
544
Reaction score
239
Location
Jordan, Red Sea
What are the limits/guidelines you have regarding the number of staged decompression dives per day?

Will you allow yourself to do more than one deco dive/day in moderate ranges (45-55mm) or approx. 15-25min of deco?

What about your daily limits limits on deeper dives in the hypoxic range (deeper than 65m) or longer decompression times?

Will you allow yourself a combination of deco dives and NDL dives in the same day?

These are just some possible combinations of dive day scenarios, but I'm just interested in your views and the personal guidelines you generally follow.

cheers
 
I don't dive that deep as most of my diving is in caves now, but my dives have been getting bigger. My current limit is 2 per day, each about 30m max depth with 45-60 minutes of deco. I've done two big dives (big for me) followed up with a small dive with my wife in the cavern zone, and I was just very careful to ascend extra slowly. Beyond that, more dives is just completely exhausting. I am starting down the path of doing more OW deco and have been considering some mix-training, so it'll be interesting to see what others say.
 
2 dives a day if deco, regardless of depth. Additional oxygen at 6m for 5 min or more after deco for insurance, very slow trip from 6m to surface, 2 hours or more between deco dives (longer is better). Had no issues to date. Dived Truk for 14 days, then Palau for 14 days. Only other rule is shallow dives last day before flying the next day and 100% oxygen before surfacing (use it all up). 24 hrs before flying.
 
I would do two dives in the 45-55 m with in the 45-50 min. of deco with a healthy SI.
This being said I would track my O2 exposure carefully and weigh in how I felt physically.
If I feel a bit off or overly exerted I will not dive or alter the plan to not push my deco limits.
After being around so called undeserved hits Im excessively conservative.

Anything over 65m with 45-60 min of deco multiple deco gasses its one a day for me.
Im old enough, not in tip top shape, have several skeletal issues with discs, so I do not push it.
Ive been on several dives that were amazing and would have loved to continue but when you deco in the Great Lakes your thermal issues come into play in a HUGE way!
The thermal effects on decompression are solid in my opinion.
I limit the amount of deco depending on how long I feel I can comfortably "safely" hang.

Having done dives in FL as well as Great Lakes it is great consideration just what the water temps at depth are.
As a part of my practice I often ascend very slowly, far less than 9m a min. usually somewhere around 5m a min.
I also watch my O2 exposure taking breaks when using 99-100%.
I do not mind the extra time @ 6m.
We also spend time just hanging in the water conditions pending on deco dives.
I also like to take my tanks off in the water if possible reducing any exertion keeping my activity to just getting out of BC and dry suit.

Just my practice I try not to push any limits but enjoy the dives immensely!
Helium makes them so much more memorable.
Enjoy

JCG
 
The depth and total dive time as well as CNS% are very important.
Normally 2 dives per day with min of 3hrs(air dive) or 4hrs(trimix) of surface interval. As I am getting older it is ONE deco dive per day for no more than 3 consecutive days.
 
More on the NDL side of your question... Me and a couple of buddies go out 4-5 times a year for Lionfish. It's not unusual for us to do 6-8 dives in a day (a couple of times one of the younger in shape guys might do 9 if we get an early enough start), with usually 1-3 of those incurring some small deco obligation (10-15 mins tops). The trick for us is good hydration and rest for the previous day or two, aspirin and continued hydration during the day, and we always finish the day sucking down a 40 of 50% at around 5-15 meters.
 
I'm down to 1 deco dive a day, I'm far more conservative now as I'm getting older and physically less capable of multiple long deco dives in a day.


Sent from my iPhone using Tapatalk
 
I am in the 1 and done camp for dives in ow that are 2 to 1 for deco. If we are doing 1 to 1 I will still do 2 a day. I am not even close to being twenty something anymore.
YMMV
Eric
 
I do one deco dive a day; all the other dives (max. 2) are shallow dives usually less than 60 ft max. well within NDL.
 
What are the limits/guidelines you have regarding the number of staged decompression dives per day?

Will you allow yourself to do more than one deco dive/day in moderate ranges (45-55mm) or approx. 15-25min of deco?

What about your daily limits limits on deeper dives in the hypoxic range (deeper than 65m) or longer decompression times?

Will you allow yourself a combination of deco dives and NDL dives in the same day?

These are just some possible combinations of dive day scenarios, but I'm just interested in your views and the personal guidelines you generally follow.

cheers
Just a general Rule-of-Thumb recommendation: should be no more than two deep deco dives a day with minimum SIT 3hrs between them over several consecutive diving days of a week or more --especially if using bottom mixes with high FN2 percentages like air or nitrox-- by Day 4 start adding more O2 profile time at 20feet/6meters with a very slow ascent (0.5 m/min or 1.6 foot-per-minute) to the surface, monitoring for signs & symptoms of slow tissue type one DCS ("niggles" to obvious acute joint & limb pain and have an In-Water-Recompression (IWR) contingency profile ready in your Wetnotes, just in case).

Better yet, take a day off to further Off-gas those N2 saturated slow tissues after three consecutive days of Deep Air diving with mandatory decompression. . .
----------


21 consecutive dive days completed here at Truk, including 10 straight days of two deco dives per day with an average 3hr SIT. Except for the North Pass site of the Oite Destroyer at 57m average depth, all deep morning dives were mostly on the wrecks of the Fourth Fleet Anchorage (San Francisco Maru, Aikoku Maru etc) with ave depths of 45m to 51m with 45min to 60min Bottom Times, and total run times of two-and-half to over three hours. All but two deep dives were on Air bottom mix, the other two using 20/20 "Tropical Economy Trimix" (for reel-line penetration of Aikoku Maru's engine room at 60m max), with 50% and 100% O2 for deco; and Nitrox30 for the repetitive dives in the afternoon with O2 deco
only- all on Open Circuit. No prompt or delayed acute DCS symptoms/signs post-dive this time compared to last year Oct-Nov, with only a few upper arm/shoulder "niggles" felt overnight once. (Air & water temperatures 27 deg C, wind chill Winter conditions with NE winds 8 to 12 knots, 1m to 2m surface water chop with scattered rainshowers inside the atoll/lagoon).

The disadvantage of tactically compensating for the deep stop slow tissue loading with elective extra O2 time of around 10 to 20 minutes maximum was expected: an uncomfortably high CNS OxTox figure result of 300 to over 500 max as tracked by the Petrel dive computer on 30/85 GF. By the start of this last week, I discarded the Ratio Deco Profile (along with Nitrox50 intermediate deco S-curve profiles emphasizing the high ppO2/"Oxygen Window" at 21m & 18m, and only slowing the ascent rate from the bottom at 10m/min to 3m-6m/min, at where that first required Ratio Deco/One Minute Deep Stop would have been), and instead followed the Petrel computer at GF's 30/85 with further conservative resetting on-the-fly of the Surfacing GF to 70 or 60, in order to extend the O2 deco profile (I really like and found this feature of the Shearwater Petrel Dive Computer most useful along with the @+5min/"predicted deco time remaining to surface staying at current depth for 5 more minutes" function). The CNS loading in this instance never went beyond 250 max.

Anecdotal Impression: I did not notice or feel any difference qualitatively post-dive using either Ratio Deco w/ Deep Stops, or Buhlmann GF's 30/85 as calculated by the Petrel Computer -both with using high N2 fractional bottom mixes of Air, 20/20 Trimix, or Nitrox30 & extended O2 profiles. The disadvantage of using elective extended O2 profiles to conservatively compensate & eliminate slow tissue loading is noted above with excessive CNS/Oxygen Toxicity rating factor, especially with deco profile implementation of the Ratio Deco Algorithm with Deep Stops.


Effects & issues of 21 consecutive Tech Dive Days with Deep Stops & elective O2 deco profile extensions.
 
Last edited:
https://www.shearwater.com/products/teric/
http://cavediveflorida.com/Rum_House.htm

Back
Top Bottom