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O2 During Safety Stop? - DanL - 09-16-2003
I'm getting old... Tired on the drives home from dives...
Nitrox really does help. How about adding O2 on the safety stop? Could carry an O2 pony and switch to it the last shallow part of local dives. Or, to avoid carrying all that, mount a 20 or 30cf O2 tank with reg on a dive float/flag, with a 15ft hose. Pull float or come back to it toward end of dive and breathe O2 for 5min or so.
Thoughts?
Re:O2 During Safety Stop? - DRE - 09-16-2003
Dan,
before you start adding the O2 I'd look at a couple of factors that might be contributing to post-dive fatigue: what are your dive parameters (depth/time), are you approaching the NDL's (or doing deco dives), how do you shape your ascents (ie do you go fairly shallow quickly, or do you incorporate some kind of deep stops in your ascent even for a no-deco dive), what kind of actual stops are you doing (3min at 15ft vs 1min@40, 1@30, 3@20 and 3min ascent to surface from 20ft), etc.
Adding O2 at 20ft might reduce your post-dive fatigue somewhat, although I believe you'll get much better results by adding some He in your mix than by jacking up your O2. If your doing a dive to 100ft on 30/30 vs EAN 32 the 30% He will be out of your system by the time you surface (if you do a proper ascent), which means that there's already 30% less residual inert gas left - it's a question of simple math above and beyond all the underlying physiological interactions.
You're only drawback would be cost of the mix, but that's a decision you'll have to make (or not make
).Feel free to PM me with any further questions.
David.
Re:O2 During Safety Stop? - ScubaDiveandTravel - 09-17-2003
Dan,
I know we spoke about this at the shop, so hopefully it's not too repetitive. For your style of diving, there is no need to be diving trimix. Your O2 idea would definitely benifit you. You will off gas about twice as fast using O2, allowing you to return to the surface much cleaner. There is a place for recreational trimix, such as cave or wreck penetration in the 100-150 range, where task loading becomes an issue. I believe the added danger of helium based diving for simple recreational, no decompression, open water diving is not worth the little bit of benifit. Helium absorbs into your tissues much faster than Nitrogen, meaning you will become saturated with inert gas much faster. You should come out cleaner if you follow a staged decompression schedule, but we are talking about no decompression diving. If your tissues were saturated with Helium at 100ft and you had to make a fast assent perhaps to assist someone, or you blow a HP O ring, ect. you would most likely come up bent. Make an informed decision for yourself and weigh the positives and negatives.
Hopefully this has been helpful.
Happy Diving,
Richard
Re:O2 During Safety Stop? - LKunze - 09-17-2003
Great points guys. I agree, the multiple stop ascents instead of just one 3 minute stop at 15 feet makes a lot more sense even for dives within the recreational limits. The first time I did a multiple stop/VERY slow ascent I noticed I felt better after the dive.
Re:O2 During Safety Stop? - john j - 09-17-2003
I agree with the multiple stop ascent idea. At least try that first. If that doesn't seem to help, then maybe try the O2 route but that's adding a bit more complication and as you know there is some additional risk too that should be considered. I wouldn't recommend the recreational trimix at all. As I've stated before, I think this is a silly course that has no real value or place in non-decompression, non-overhead environment, recreational type diving.
Are you in good shape aerobically? Regular exercise might also be a solution. Also make sure you are very well hydrated before and after the dive. I'm convinced that post-dive fatigue is actually sub-clinical decompression sickness. Anything that you can do to reduce the chance of DCS might reduce your fatigue level.
Re:O2 During Safety Stop? - Freedive WI - 09-17-2003
1. Proper hydration
2. Deep stops
3. Proper breathing pattern- you can easily give yourself CO2 headaches by breathing wrong.
HE2 might be absorbed faster, but it also comes out faster. IF you have the skill, meaning proper bouyancy control and ability to make controlled ascents, I see no problems with switching to triox. Some of the bad hype that it gets (not for recreational divers) is the EXACT same story that we used to hear 10-12 years ago about nitrox, and now look what has happened to that! In another 10-12 years triox will be no big deal.
It is a bit more expensive, but if I wear one of those rebreather guys I wouldn't dive anything but triox since the expense issue would have been negated at that point.
I think that you'll find the biggest difference by adding in some deep stops to your dive plan. I know that it made a huge difference in my post-dive fatigue. Actually, it elminated it.
jon
Re:O2 During Safety Stop? - john j - 09-17-2003
Good summary.
On the triox issue...I dive almost exclusively with trimix in my CCR, even on the shallow dives (just easier to leave the trimix on than switching to a different tank) so I am definately a supporter of trimix, a BIG supporter. Just not for 130ft or less dives, that are single tank, no-decompression and non-overhead environment (a.k.a recreational dives). There is just no need for it, it adds risk in my opinion, and the diver just isn't down long enough to truely benefit. I'm not saying people shouldn't be allowed to do it. You can spend your money however you want. If you want to waste the $20+ per fill, that's your business-go right ahead. I just think it's silly. My funds are limited, so I would rather spend my money where it will count more, so I'd go for the advanced nitrox/deco class or extended range before I'd go with recreational trimix. Or I'd go on another dive trip or something. I just don't see what you really get out of recreational trimix. Education and skill practice I suppose. Now I've changed the subject..sorry. Anyway, I thought the previous summary was good-and the idea about keeping breathing control was a great one. I suppose that the free divers really are good at breath control while SCUBA diving. Free diving sounds like a great skill set to compliment SCUBA diving skills.
Re:O2 During Safety Stop? - freedivernd - 09-17-2003
From JohnJ
Quote:. I suppose that the free divers really are good at breath control while SCUBA diving. Free diving sounds like a great skill set to compliment SCUBA diving skills.Good supposing JohnJ. ;D I'm convinced nothing extended my scuba air time more than breath hold diving.
Fred
Re:O2 During Safety Stop? - lrmoll - 09-19-2003
Recently NAUI changed its training. Instead of one stop at 15 the first stop is at half max depth with a shorter safety stop at 15.
Re:O2 During Safety Stop? - lrmoll - 09-24-2003
I wonder Fred. How do you resist the urge to hold your breath when SCUBA diving after training so much to do just that?