Too Deep, Too Often, Too Soon?

[ricki]

I was speaking to Paul Kotik this morning about a minor lightness (I noticed no other symptoms), I perceived at the top of my head during some of those scooter dives a few days ago. I wondered if it might have been the product of an improper breath up and recovery (seemed normal), inadequate surface interval (went to ten+ minutes), inadequate hydration (could have drank more) or ???

One of his points was that unless I was used to going to that depth on breath hold dives in that frequency the attendant stresses could bring out something like that perhaps something worse as well. He described some serious instances of lung squeeze and trachea problems. He strongly advised going slow with depth increments over weeks to allow things to acclimate to the increasing rigors of depth. Makes good sense.

Unlike having to swim down and back which might take some time and repetition to achieve, a scooter or sled can allow a person in a near quiescent state to rapidly reach depths. Going down to 120 to 150 ft. repetitively seems readily within reach but may not be that great an idea, too soon anyway. The experience has felt good (more accurately great) to date but then again, strange problems can set in suddenly with minimal warning at times.

What physiological hazards and precautions come to mind in doing something like this? I wonder if new sled divers have had issues like this?

Thanks,
Rick

[harbour seal]

not exactly addressing the depth issue directly but....

in the event of scooter malfunction, i would consider not going deeper than you are able to swim back to the surface under your own power.

also i have read of freedivers experiencing serious DCS symptoms from repeated deep dives using a scooter. kirk krack comes immediately to mind (although at the time i don't think that DCS in freediving was considered a big issue).

i expect that lung squeeze and co2 narcosis would be threats in any dives to 50m+, not to mention the dcs, especially if you haven't allowed time for gradual physical adaptation. those divers who have experience with these depths are obviously the best sources of info on these matters.

cheers,
sean

ps. not sure why you needed to start another thread as your previous thread from 2 days ago addressing basically the same issues

[laminar]

DCS definitely would be a concern, especially given the potential for shorter recoveries and VERY rapid ascents. The latter being probably the most important for avoiding DCS and the former for avoiding a blackout.

Kirk did do a silly deep dive on the scooter a long time ago...

Pete

[ricki]

I had no intent to launch a redundant thread, in my mind it was not. Here's why, I just picked up an Oceanic Geo, plan on 10 minute or more surface interval between dives, plan to ascend slowly in the upper 33 ft. and depending on circumstances may even do an O2 safety stop at some point(s) in the day. So, at least I have a starting plan for trying to manage DCS which is fairly familiar from study and misadventures over several decades.

Lung squeeze aside from a theoretical issue that almost never impacts SCUBA divers or shallow free divers, different story. The same goes with trachea issues, new and unfamiliar ground for me. It seems like there may still be other issues. In constant ballast free diving you get there on your own and it is usually with smaller depth increments and down intervals over time allowing some acclimatization. This acclimatization could be cut short in scooter free diving exposing the body to rigors that it may not be ready for with limited warning.

Scooter diving can be easy, perhaps too easy to undertake deeper dives and a fair quantity of repetitions. Sounds like the making of some possible strange physiology experiments, hence my original question, which I could use some more input on.

I totally agree on going no deeper and longer than you have air to return from. Probably for around 115 ft. perhaps a bit more currently I think it should be doable. I am used to gear failures from kiteboarding and to a lesser degree diving. Over time, things can happen, just the way it is. So, I setup a 13 cft. pony bottle to carry horizontally in the small of my back. I wouldn't want to routinely free dive with it but with a scooter it may fall within a negative pressure area limiting drag. This is a fair amount of specialization of gear, procedures and precautions apart from regular free diving, still a good scooter session can be pretty intriguing.

Rick

[ricki]

Originally Posted by laminar

DCS definitely would be a concern, especially given the potential for shorter recoveries and VERY rapid ascents. The latter being probably the most important for avoiding DCS and the former for avoiding a blackout.

Kirk did do a silly deep dive on the scooter a long time ago...

Pete

Thank you for your input. You can be tempted to just go and short cut recovery time. Still, with a good handle on possible consequences and a plan for residual nitrogen management it should be easy to observe reasonable precautions. How fast an ascent is too fast promote an untoward risk of BO, are there depth intervals which are more critical than others in this regard, like ? ft. to the surface? Subjective questions, still input on this is welcome. Was that deep scooter dive on a wreck in the Caymans?

Rick

[harbour seal]

rick,

safety issues aside, scooters sound like a lot of fun.

keep us updated on your progress.

cheers,
sean

[ricki]

Originally Posted by harbour seal

rick,

safety issues aside, scooters sound like a lot of fun.

keep us updated on your progress.

cheers,
sean

Hello Sean,

Will do, hope to learn some more this weekend. It will interesting to see how wearing the bailout bottle works out and the Geo in tracking SCUBA combined with free dives over time. I usually avoid SCUBA diving entirely anymore but this weekend may unavoidably involve a mix.

Does anyone have any stories or experiences about physiological problems that have come up for new sled free divers?

Rick

[fcallagy]

Hi ricki,
Be careful about that mix others have got dcs freediving after scuab even if relativly shallow. There are no tables to base it on so the best advise is dont mix it. Obviously surface snorkelling aint an issue but even to maybe 15m there may be some micro bubbles in some of the slow dissues. In effect you are recompressing them again and then ascending very fast. Do this over a period of time and !!!!. I know one person on this board suffered from dcs while freediving after scuba.

[ricki]

Originally Posted by fcallagy

Hi ricki,
Be careful about that mix others have got dcs freediving after scuab even if relativly shallow. There are no tables to base it on so the best advise is dont mix it. Obviously surface snorkelling aint an issue but even to maybe 15m there may be some micro bubbles in some of the slow dissues. In effect you are recompressing them again and then ascending very fast. Do this over a period of time and !!!!. I know one person on this board suffered from dcs while freediving after scuba.

thank you for the warning. I spoke to tech support at oceanic yesterday about the geo's advertised ability to handle deco planning for both activities combined. the say it will do it but I will be conserative anyway. no longer a good deco test dummy choice.

I met a guy about 15 yrs. ago. he did some repetitive scuba on the cayman wall the day before. the next day he free dove to 100 ft. three times. had a real nasty type II dcs hit that didn't fully respond to recompression. the story sticks with me.

rick

[kelp princess]

Originally Posted by fcallagy

Hi ricki,
Be careful about that mix others have got dcs freediving after scuab even if relativly shallow. There are no tables to base it on so the best advise is dont mix it. Obviously surface snorkelling aint an issue but even to maybe 15m there may be some micro bubbles in some of the slow dissues. In effect you are recompressing them again and then ascending very fast. Do this over a period of time and !!!!. I know one person on this board suffered from dcs while freediving after scuba.

i am extremely curious abou this theory with micro bubbles and freediving after scuba. in fact it may be the clue to a mystery i haven't had resolved for myself and an apparentt dcs case.

any insight any of you guys have would be extremely useful:

my situation:

9 day expedition to monitor lemon sharks and pick up geological samples in the exumas (bahamas) about 3 weeks ago. freedving (snorkelling to max 15 meters) everyday, some days freediving before and after scuba diving and mixed gas rebreather diving. no erractic profiles, no rapid ascents, no overexertion. most scuba dives were recreational, no days of multiple scuba dives.

-last scuba dive on 7/29 at 12 noon
-flight home out of miami to SF on 7/31 at 8:30 pm (more than 48 hours later)
-no pain or syptoms on plane
-8/1 exhaustion and weird tingling (symmetrically) in calf muscles, swollen hands and pins and needles
-8/2 still sorta tired and still weird tingling in legs ( feels like lack of circulation), sporadic cramping from tingling inlegs
-8/3 2 quick flights back and forth from SF to San Diego, random leg tingling (both legs) through out the day
-8/4 leg cramps extreme call DAN get no good information or help (unbelievable). go to emergency room and see a hyberbaric docotr who doesn't know or have answers so to be sure sends me to chamber for pressure test: 3 atms for 1.0 hrs., 2 atms for 1.5 hrs, surface up to 1 atm 30 mins

-8/5 thru 8/7 3 more chamber rides
-8/6 hands noticeably not tingly and not swollen
-8/6 tingling in legs transitions to what i would assume is a more typical dcs symptom of achey writst, hip and back of knee ares (no tingling but extreme aches in joints)
-8/7 last chamber visit and no aches and no tingling

-8/10 today go to regular doctor (internal medicine) and she takes blood sample to see if everyone is crazy and perhaps i just had a virus?

(btw i never had a headache, dizziness, vision blur or fever...)

what do you guys think?

kp

[cdavis]

Ricki,

If you are still diving half lung or close, that is very relevant to deep scooter diving. It greatly increases the chance of encountering squeeze injuries, but decreases the chance of DCS and intensity of n2 narcosis, not sure about c02 narcosis. Eric F has some experiance and comments on this that are appicable to what you are doing. Seach FRC for his threads.

I will follow your experiance with great interest. Jon and Longfins introduced me to scooter diving last month and it is a major Wow. I plan on doing lots more.

Connor

[Jon]

Any time your freediving after scuba your opening yourself up to a DCS hit- and most of those hits will be type II due to the rapid ascent rates experienced in freediving. The general rule of thumb is freedive first and scuba second- never the other way around.

Kelp Princess,
from your profiles it sounds like you got bent. I've read that the WKPP don't even let their divers go back in to retrieve their own deco bottles after a big cave push because too many got hit from that simple dip back down to 20' after decoing out. A simple freedive after a rebreather/mix/deco dive should have the same effect- whether or not your breathing off a tank when it happens. I would separate your activities a lot more, but that's just me.

Ricki,
I wear a spare air when scootering. I know all the bad points about them for scuba, but it's all I need in case of a scooter flood at depth. I've worn one for 8 years now and never had to use it once- but it's always there just in case. Your idea of wearing a 13 cuft bottle has some merit, but I just never wanted anything that bulky on me while diving- the spare air is bad enough.

I've been wreck diving with mine to 105' with repeated excursions and never had an issue with DCS- sub-clinical or otherwise. I've always stuck with the rule of keeping my surface interval at least 2-3 times as long as my bottom time and it's worked so far.

I have seen some examples of the freediving DCS tables put together by some Spanish doctors. I think that they were published in Freediver magazine a few years ago- which has since gone out of business. They were based on longer surface intervals for deeper depths and longer bottom times at those depths. None of them had any safety stops, or ascent rates, built into them. they were all based on proper surface intervals.

There's no computer that I ma aware of that has any kind of a proven deco algorithm in it for freediving- let alone mixing freediving and scuba together. IF there was one we'd have heard a LOT more about it on here. I don't think I would trust that thing as far as I could throw it.

Just my $0.02

Jon

[ricki]

Originally Posted by cdavis

Ricki,

If you are still diving half lung or close, that is very relevant to deep scooter diving. It greatly increases the chance of encountering squeeze injuries, but decreases the chance of DCS and intensity of n2 narcosis, not sure about c02 narcosis. Eric F has some experiance and comments on this that are appicable to what you are doing. Seach FRC for his threads.

I will follow your experiance with great interest. Jon and Longfins introduced me to scooter diving last month and it is a major Wow. I plan on doing lots more.

Connor

I am still evaluating diving with fully filled lungs, new to me but not to lots of other free divers. Thank you for your thoughts about relative risks of the two approaches and the direction for more info.

I came over to Andros for a couple of days. Unfortunately, my new scooter has some serious drive shaft linkage problems so no powered dives for me this trip. I was looking forward to checking out the wall and blue hole with it, next time. Went to the "dark side" using tanks for a wall and shark dive today. So, I am probably screwed up for free diving with residual nitrogen for a while. May get some in Monday but perhaps not even then out of caution.

Scooter free diving is a trip, with all the mobility and expanded capacity. I thought it was more established than it might be. Like anything new, folks may get hurt learning what works and what is best avoided.

Rick

[island_sands]

Just the title of this thread attracted my attention.

Can never be too deep or too often

[samdive]

KP/Ricki

Don't think it's a secret that I got a nasty DCS freediving after scuba - it was the day after a 40m scuba dive - 16 hours in between and I was only freediving to 15m

My docs, and now AIDA Education, agreed that freediving after scuba should be treated like flying - don't do any until your dive computer is cleared. If you don't have a dive computer, wait 24 hours.

it's hard to put a depth on "what is freediving, what is snorkelling" so I'd say, just stay on the surface until your totally bubble-free

S