Intro to recreational deep diving

[Dtaine]

I just completed my AOW and have several dives to 90-100 feet and am planning several with max depth of 120 in the near future. I will be diving a single HP 120, no pony. Diving with permabuddy.

I have planned my rock bottom PSI and EANx mixtures at 1.3 PO2 at max depth and wanted any other helpful information/preperation that was out there.

Nitrogen Narcosis - Never experienced it. Tips or advice for a first encounter?

I've been to 130' without noticing narcosis, but I know it was affecting me to some extent. If you notice anything beyond ordinary be safe and turn the dive.

Loss of buoyancy at depth - Do you adjust continously on descent or at depth?

Continously, you shouldn't have a problem unless you have an undersized BC. You can calculate this beforehand to make sure it's good.

NDL - Not pushing it to the limit (ie 1 min remaining at the begining of ascent) do I need to account for longer ascent time in NDL? At 120 ft, using 2 minutes to reach my deep stop at 60 feet, how much NDL would you start your ascent with? (ongassing/offgassing threshhold)

Anything else to think about?

For your first dives this deep turn a few minutes before you think you will and don't push the NDL. It'll take longer to get to the surface if something goes wrong and you don't want to be pushing deco just because something held you up (Like taking 3 minutes fumbling with your mask and gloves)

Maintaining more than 8 pounds of thrust, continuously for several minutes is a huge effort and will also send your SAC rate thought the roof.

If you have a BC failure, and need to swim it up from the bottom (if there is a bottom) it's also possible that you'll also be OOA at some point during your ascent due to the increased effort and air consumption.

Although I've never measured it, i'm also not certain that an average diver can actually maintain 8 Lbs (more actually, since you want to move) of thrust over an extended period.


OK: Torn inflator hose (the big flexible one), broken or cracked elbow, elbow pulled out of BC and hole is damaged, failed or missing elbow gasket, torn or punctured bladder, broken inflator (valve assembly), BC seam failure. Lots of others I can't think of right now.

Before you say "these are all really unlikely", I'd like to mention that I had #1 on the list on my #7 OW dive ever, on a wall dive.

BC's do fail, and it's definitely a consideration on deeper dives; but I don't think you need a drysuit or a redundant bladder for recreational dives to 120. Best to make sure your gear is well maintained and that you and your buddy have a set amount of air for reserve.

Nobody is saying "if you go over 100', you'll die" (well maybe some are). All we're saying is that deeper divers require more thought, more planning, more training and maybe different equipment.

Just as an example, what happens if your buddy gets caught in some discarded mono-filament or steel leader and now you're 10 minutes over the NDL and have a deco stop. You've been working harder and are almost out of gas, and your buddy who didn't have enough to handle his own deco stop certainly doesn't have enough to handle yours.

Carry a good knife/shears, keep a reserve on air (definitely possible with hp120's even to 120 feet), if it's a boat dive you might consider having a drop tank off the boat. Someone can just as well get entangled and hit deco on an 80 ft wreck as a 120 ft wreck. Even somebody with doubles can get entangled and be unable to make deco stops. Research the site you're going to, don't push anything on the first dives, and keep an eye out for entanglement hazards.

When you start working closer to the edge, little problems can easily turn into major disasters if you didn't plan for them before hitting the water.

If you're thinking about wandering around near the edge of the no-deco limit, I'd suggest taking a deco class where you'll learn about all the things you need to be aware of and how to plan for and handle them.

Lots of people do 120' dives every day with single tanks and live to tell the tale, however it's only because nothing bad happened. You'll be much safer if you know that you and your buddy can handle almost anything that's likely to happen.

Terry

I agree that taking more courses is a good idea, but I don't agree that diving to 120' with single tanks and a wetsuit is beyond a reasonable level of risk as long as the divers understand those risks and prepare for them as best they can. Let the flaming begin .... :fire:

 

[scubadiver888]

Im worried by the admission on here that someone cant refit and seal their mask with gloves on! If you cant do that you should NOT be diving with those gloves on. Its a basic and absolutely essential skill.

At this point (12 cold water dives) I can get my mask on with the gloves on. To practice, I put my gloves on then TRY to get my mask on. I then have my buddy check my mask. So far I've been unable to get all my hair out of the mask. By end of next summer, I might be able to do it. Right now I'm not worried because I can get my mask clear enough that I could dive with it. It is not like I have long hair. It would be more like a mask that doesn't fit quite right. I'd be clearing it every few minutes. I just hate that and would rather call the dive.

If the mask was leaking to the point that I had more than 1mm of water at the bottom of the mask every minute then I would agree it is a problem but having a few hairs in the skirt and the mask leaking to the point it would be flooded in say 2 hours, this is not a huge problem. It is just annoying. For me, if I'm not enjoying the dive I'll call the dive.

Also, I'm talking about this in the current context. If I was on a 100' dive and had to get my mask back on PERFECTLY I'd probably take the rest of the dive to do it. Would be easier to just get the mask back on 'good enough' and call the dive. If I lost my mask 5 minutes into a 60 minute dive, I'd take the time to get my mask back on and totally clear. It would probably take me a good 3 to 5 minutes to do it.

 

[Web Monkey]

BC's do fail, and it's definitely a consideration on deeper dives; but I don't think you need a drysuit or a redundant bladder for recreational dives to 120. Best to make sure your gear is well maintained and that you and your buddy have a set amount of air for reserve.

If ditching your weights won't make you positively buoyant at any point during your dive (overweighted or non-ditchable), or if ditching your weights is unacceptable or useless (virtual or physical overhead), you need redundant buoyancy.

Equipment fails. Even brand new or recently serviced equipment.

Even somebody with doubles can get entangled and be unable to make deco stops.

"Unable to make deco stops" is simply not an option. A blown deco stop that's significantly past the NDL can easily lead to a frothy agonizing death while all your friends watch in horror.

Research the site you're going to, don't push anything on the first dives, and keep an eye out for entanglement hazards.

How can you research monofilament?

I agree that taking more courses is a good idea, but I don't agree that diving to 120' with single tanks and a wetsuit is beyond a reasonable level of risk as long as the divers understand those risks and prepare for them as best they can. Let the flaming begin .... :fire:

No flames. People are free to take whatever risks they want. I choose to not risk my life on a single cloth bag.

Terry

 

[String]

At this point (12 cold water dives) I can get my mask on with the gloves on. To practice, I put my gloves on then TRY to get my mask on. I then have my buddy check my mask. So far I've been unable to get all my hair out of the mask. By end of next summer, I might be able to do it. Right now I'm not worried because I can get my mask clear enough that I could dive with it. It is not like I have long hair. It would be more like a mask that doesn't fit quite right. I'd be clearing it every few minutes. I just hate that and would rather call the dive.

I still find that extremely worrying. What equipment did you use to certify with? No student will pass a course (or shouldnt) with ANY agency if they're incapable of a mask remove and replace in a sensible time frame. Gloves aren't exactly technical equipment. Thousands of people certify every year wearing 5mm gloves or even 3 finger mitts.
I still maintain if you are unable to complete this most basic of skills quickly and easily you should not be diving with that particular piece of kit.

 

[Atomic_Diver]

Well as for bouyancy you should adjust to stay netural, or slightly negiative as you go down, then when you reach bottom you should adjust to stay netural. As far as nitrogen narcossis you really can't do much but ascend to a shallower depth if you are hit bad, really i think the only cure to Nitrogen narcossis is to dive Trimix which uses helium to replace nitrogen, or if you don't want to take a trimix course they do have a class called Recerational Trimix, and Helitrox which cost about $400.00

 

[Rick Murchison]

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[Bismark]

Well as for bouyancy you should adjust to stay netural, or slightly negiative as you go down, then when you reach bottom you should adjust to stay netural. As far as nitrogen narcossis you really can't do much but ascend to a shallower depth if you are hit bad, really i think the only cure to Nitrogen narcossis is to dive Trimix which uses helium to replace nitrogen, or if you don't want to take a trimix course they do have a class called Recerational Trimix, and Helitrox which cost about $400.00

To the OP, I would strongly suggest that for your personal safety you back off the throttle considerably. If you are having issues with buoyancy control to start with, adding helium to your tank could kill you. Period. Diving trimix is not as simple as just replacing nitrogen with helium and off you go. The properties of helium can cause you considerable grief if you do not have rock solid buoyancy control.

To Atomic Diver. I would suggest you become more knowledgable about this topic before you recommend this to anyone. You are advocating something that could kill them without the proper skills. I do not believe any instructor could in good conscience offer trimix training to someone with the limited experience either yourself or the OP has. While no doubt your intentions are good, and you are correct in regard to the narcosis issue, in this case, based on your experience as stated in your profile, you are trading the devil you don't know for the devil you really don't know.

 

[Dtaine]

If ditching your weights won't make you positively buoyant at any point during your dive (overweighted or non-ditchable), or if ditching your weights is unacceptable or useless (virtual or physical overhead), you need redundant buoyancy.

Equipment fails. Even brand new or recently serviced equipment.



"Unable to make deco stops" is simply not an option. A blown deco stop that's significantly past the NDL can easily lead to a frothy agonizing death while all your friends watch in horror.



How can you research monofilament?



No flames. People are free to take whatever risks they want. I choose to not risk my life on a single cloth bag.

Terry

Your right that redundant buoyancy is a good idea, and with regard to entanglement you can't guarantee mono filament or other loose lines won't cause a problem.

As far as PADI's concerned though, redundant buoyancy within recreational limits isn't required. Maybe it should be, after all I'm recently trained within this diving area. Looking back at the Deep Diver Manual I can't find any references to BCD failure issues. Why this isn't addressed I'm not sure .... it certainly brings up another question as to what PADI's training standards should include

 

[scubadiver888]

I still find that extremely worrying. What equipment did you use to certify with? No student will pass a course (or shouldnt) with ANY agency if they're incapable of a mask remove and replace in a sensible time frame. Gloves aren't exactly technical equipment. Thousands of people certify every year wearing 5mm gloves or even 3 finger mitts.
I still maintain if you are unable to complete this most basic of skills quickly and easily you should not be diving with that particular piece of kit.

Since you asked, I was certified in warm water and did not need to use gloves.

Your obsession with being able to get your mask removed and replaced in a sensible time frame makes me think of people who cannot parallel park. I can see you as a driving examiner, failing people who cannot parallel park.

Do you get your mask kicked off a lot? In warm water I can remove my mask, throw it away, find it, put it on, clear it in a matter of seconds. This is because I practised the exercise. Can I do that in cold water? No but then I don't have a lot of practise yet. Will I practise it and get better at it? Yes. Am I going to do it because you think it is an absolute necessity? No.

I have NEVER had my mask removed underwater outside of doing it myself. I've had my regulator kicked out once when I was diving the same location as a Discover Scuba Dive. I've had a rental mask strap break and I was without a mask. Ended the dive without a mask. I don't dive with people who would be so careless as to kick my mask off (at least not in cold water).

You might want to double check ALL agency requirements. For the few I know about, mask removal and replacement is required in confined water and not open water. There is nothing saying a student has to wear gloves. A good dive instructor will have students do it with the same kit they'd use in open water but technically does not have to.

Even in confined water, I strongly doubt most agencies have a requirement of "in a sensible time frame".

If you hold your students to a higher standard that is great. My instructor had me do things that went beyond the PADI requirements for OW (actually I've since learnt some things I was required to do go beyond AOW) but the things he added were things he knew I might need some day.

 

[Sas]

Since you asked, I was certified in warm water and did not need to use gloves.

Your obsession with being able to get your mask removed and replaced in a sensible time frame makes me think of people who cannot parallel park. I can see you as a driving examiner, failing people who cannot parallel park.

If you can't parallel park you can just keep driving and find another spot that doesn't require it. Underwater without a mask, it might be difficult to move along and ignore it . Maybe it is just me, but I have a bit of trouble reading my gauges without my mask, however I would just ascend if needed and I can ascend without my gauges. I also find it very uncomfortable having really cold water on my face for a prolongued period (I guess my eyeballs freeze or something ). Warmer water, mask loss is no big deal. I carry a back up on dives just in case I lose it just so I don't have to end a dive because of a lost mask.

Do you get your mask kicked off a lot? In warm water I can remove my mask, throw it away, find it, put it on, clear it in a matter of seconds. This is because I practised the exercise. Can I do that in cold water? No but then I don't have a lot of practise yet. Will I practise it and get better at it? Yes. Am I going to do it because you think it is an absolute necessity? No.

If you can complete a dive safely without your mask in warm or cold water, I wouldn't be concerned too much about not being able to replace it. I mean, I think it is silly to end a dive or have an uncomfortable dive swimming around without a mask in cold water because you can't replace your mask, but to each their own.

I have NEVER had my mask removed underwater outside of doing it myself. I've had my regulator kicked out once when I was diving the same location as a Discover Scuba Dive. I've had a rental mask strap break and I was without a mask. Ended the dive without a mask. I don't dive with people who would be so careless as to kick my mask off (at least not in cold water).

I think it is the person who gets their mask kicked off who is careless actually. If you get it kicked off then you have swum into somebody's feet Though twice I've had someone land on my head and knock it off, I get annoyed at those people (but they have both been OW students who were descending feet first... not my buddy!)

You might want to double check ALL agency requirements. For the few I know about, mask removal and replacement is required in confined water and not open water. There is nothing saying a student has to wear gloves. A good dive instructor will have students do it with the same kit they'd use in open water but technically does not have to.

I had to do all skills in OW including mask skills. I was told that it was a requirement of my agency and I don't have any reason to disbelieve them but do not have a requirements list handy (SSI).

But yea, if you can't replace your mask, whatever. I just think it is silly to dive with gloves that prevent you from doing such a simple skill as it just means if you lose it or it gets dislodged you will have a dodgy dive after that. I was doing a wreck dive the other weekend and got to the bottom and my mask came off a bit within minutes of starting the dive, after paying $58 for the boat ride, $25 for a Nitrox tank hire and driving for an hour and a half leaving very early in the morning, I would be real annoyed to have to surface because I can't replace my mask!!!