no safety stop after 53' dive

[boulderjohn]

My impression of boulderjohn's post was that the necessary deco stops were done. This second safety stop (at the surface) is not required but it certainly won't hurt. Think of it as a "best practice."

That's correct. I just looked it up in my NSS-CDStext, and the recommended time was 5 minutes, not 10. It is not a widespread practice, and I know of no research related to it.

 

[Adobo]

My impression of boulderjohn's post was that the necessary deco stops were done. This second safety stop (at the surface) is not required but it certainly won't hurt. Think of it as a "best practice."

I'm not at all plugged in with the latest recommendations from any of the agencies but... I have never heard of this suggestion formally discussed before. Additionally, the context of this discussion is a diver who missed a safety stop after his 6th open water dive. Put a different way, this is in the context of a recreational dive.

From reading scubaboard, I am under the impression that the necessity of safety stops is already misunderstood by some newer divers. In fact, recently there was an incident where a dive team opted to do a safety stop even though one of the divers was dangerously low on gas. That dive ended with one of the divers dying.

I would suggest that this practice is in of itself benign or even perhaps beneficial but weighed against the exposures involved in recreational dive profiles, it seems quite unnecessary. Weighed against other considerations, boat dives in the ocean for example, this practice becomes less benign.

I would caution against promoting this kind of thing as a best practice to new divers. It might be fine in a spring but out in the ocean, not necessarily.

Note: I am not against waiting 1 or 2 minutes before getting back on the boat. Under the natural course of things, a diver will likely take at least 2 minutes before he can get back on the boat anyway. I just find it unnecessary to linger on the surface for 5-10 minutes after a dive thinking there is some kind of known benefit when there really might not be. This not only can be uncomfortable in rough seas but also affects the other divers/dive teams either still in the water or waiting on the boat.

 

[Zen Diving Inc.]

From reading scubaboard, I am under the impression that the necessity of safety stops is already misunderstood by some newer divers. In fact, recently there was an incident where a dive team opted to do a safety stop even though one of the divers was dangerously low on gas. That dive ended with one of the divers dying.

So a diver died because of a safety stop or low gas on a safety stop...? What, did he drown? I'm willing to bet there is far more to that story that what you included. Please provide the link.

I would suggest that this practice is in of itself benign or even perhaps beneficial but weighed against the exposures involved in recreational dive profiles, it seems quite unnecessary. Weighed against other considerations, boat dives in the ocean for example, this practice becomes less benign.

Safety stops are not... Benign. Think about what you have said... "exposures involved in recreational dive profiles...boat dives in the ocean for example..." What or where is the comparison? What exposure are you talking about? Scuba diving in general, boat traffic, cold water, giant sharks, newbie divers? What are you talking about?
Better to get out of the water and possible exposure to ??? then stay and do a safety stop. That at the very least is an interesting point of view. I can say from experience that there have been a few times I skipped a safety stop to reduce my exposure to being cold in a drysuit having to pee, or spearfishing off florida coast and garnering the attention of a few blue sharks wanting my dinner which I handed over at the tip of my spear. Aside from a life threatening situation or serious discomfort I cant see any reason to plan on not making a safety stop.

I would caution against promoting this kind of thing as a best practice to new divers. It might be fine in a spring but out in the ocean, not necessarily.

I you plan and prepare properly, exposure would be reduced to start with. Taking all things into consideration, maybe the dive should be shorter so you can make that safety stop

 

[DandyDon]

This is the first I've heard of a safety stop on the surface.

I think I heard it from Dr.Deco, and I think he might have had another name for it - altho one could call it whatever makes sense.

That's correct. I just looked it up in my NSS-CDStext, and the recommended time was 5 minutes, not 10. It is not a widespread practice, and I know of no research related to it.

NASA.

 

[NAM001]

Like others have said the basic answer is NO you dont have a problem with the 3 min. Other things in your post tend me to ? that you believed that the 3 min was necessary to avoid a deco concequence. That may be from the instructor never actually conveying the purpose of the SAFETY stop as opposed to manditory stops. If that is the case perhaps you MIGHT want to look for another instructor to further your training with when you move onto aow ans nitrox. The depth issue i havent figured out . perhaps it was a shallow reef that allowed you to follow 10 above but the part of unexpectedly on the surface suggests that you were not aware of your depth, perhaps from watching the dive scenery and not the gages or listening to your body/ears. that will work it self out with more dive time. I am sure your 7th dive will go better than the 6th. Good Luck

Today was my 6th open water dive. Five divers following DM. MY friend goes thru air much faster than I do so DM took her back to the line so she could ascend. We stayed down a bit longer looking at turtles.

DM was leading thru a narrow passage, I was not comfortable with this, so I attempted to follow 10' above. Thought I was hovering just about them when I realized I had gently surfaced! I am concerned because I didn't do the safety stop at 15'. I was breathing the entire way up.

This was the last dive of the day. I stayed in the water for 5 minutes before climbing onto the boat platform. Should I be concerned about the lack of stopping for 3 minutes at 15'?

It's been 5 hours since & I feel fine.
Thank you for your help!

 

[ganu76]

... recently there was an incident where a dive team opted to do a safety stop even though one of the divers was dangerously low on gas. That dive ended with one of the divers dying.

A few years back I got wrapped up with someone's student and an OOA situation. While the student used MY octo as the of us ascended, the student's INSTRUCTOR remained at 15' until his precious safety stop was complete. I'm fairly sure that the student never broke 50' during the dive, and the OOA occurred at about 35'.

The instructor needs to be whipped. Not only was a safety stop NOT REALLY needed, but there was a real-life emergency and the instructor did nothing other than remain at 15' for a full three minutes while someone else took care of his student on the surface.

 

[Thalassamania]

I would mention that a single dive without SS is one thing, however when doing multiple dives over multiple days, safety-stops become much more important. Multiple dives throw in many other factors mentioned above such as fatigue, cold, dehydration etc.

That has no effect on the "need" for a "safety" stop. Such stops are outside of the models (except for the "PADI Patch"). It should be noted that slowing an ascent in the region above 20 feet, is not a problem.

Dive computers are conservative- some are more aggressive than others. If you own a more 'aggressive' computer, again safety stops become a bit more important.

Once again, such stops are outside of the models and to the best of my knowledge there are no computers so aggressive as to warrant the use of a "safety stop" for a healthy ascent, after all, a required safety stop, is by definition, a decompression stop, except where PADI patches their model (and does us a linguistic disservice) by requiring a safety stop under specific circumstances.

A missed safety stop can be 'fixed'. You can descend immediately (air supply and conditions permitting) and complete your safety stop. Bubble formation tends to occur around 15mins after surfacing.

Very, very bad advice. First of all it is without reason or rationale. Second of all you are now adding a danger of bubble pumping where is nothing to be gained ... you've already made the ascent and re-pressurization to a mere 20 FSW is irrelevant.

A missed safety stop dramatically increases the amount of silent bubbles, which are thought to increase the chances of 'real' bubbles on subsequent dives. One study showed that a one minute stop at 6m, and a further 3 min stop at 3m reduced the amount of these silent bubbles to practically zero after a surface interval of just 45mins. I can't remember the exact profile on this test (ie. depth and time) but it was typical of a recreational dive to around 25 meters.

Indeed a safety stop has been shown to reduce the incidence of "silent bubbles." For years we dove with the mistaken notion that if we surfaced properly (old school: 25'/minute, then 60'/minute, now 30'/minute), and did not exceed the USN Decompression Table for the deepest point in our dive we would avoid bubbles forming and creating decompression sickness. Then came the Dopplers a device can monitor bubbles that were passing through the heart. In the late 1960s Dopplers were used to check for bubbles series of no-D dives. It was found that bubbles were created during even during these dives and these bubbles did not appear to do any damage. They are usually filtered out by the lung capillary beds with no obvious symptoms and were called "silent bubbles." These asymptomatic bubbles are thought to be indicators of approaching decompression problems and this lead to the pioneering work of Pilmanis, Spenser and latter Huggins. But ... be that as it may, there is no information to support the idea that silent bubbles are any problem (or even, for that matter, that doppler detectable bubbles and bends are one and the same) or that shallow re-pressurization has any effect what-so-ever on silent bubble formation.

Personally I aim for a 5min safety stop on most of my dives- especially the last of the day. I also try to make an anally slow ascent from 3m to the surface. Slowly winding up an SMB line really helps you make a sloooow ascent.

Slowed ascents from 20 fsw on up are a good idea, and will do no harm.

Thalassamania, why the difference between a safety stop and an asymptomatic deco stop? I can think of several reasons (more like assumptions and risk analysis ) for this but I'm struggling with the "never" part for a safety stop.

Think about it this way:

Decompression stops are required and if they are missed they need to be made up somehow ... and it needs to be done rather quickly. Conventional wisdom would be to follow omitted decompression procedures within 5 minutes if non-symptomatic and to evacuate to a chamber breathing pure oxygen, if symptomatic.

Safety stops, on the other hand, are (by definition) not required and may be ignored with impunity. They should not be made up, in fact returning to the water to make them up puts you in danger (however slight) from bubble pumping due to the short nature of the safety stop.

There are some very simple rules that I follow:

1) slow your ascent, especially as you approach the surface.
2) deep stops are good.
3) gas in your tank does you no good, time at 10 to 10 feet may do you a lot of good.
4) once out of the water, do not re-enter the water to make up a missed safety stop.
once out of the water, do not re-enter the water to make up a missed deco-stop, unless you are symptom free and it is within 5 minutes of surfacing, and you have an omitted deco plan.
5) do not make short, shallow dives, even to shallow depths, after surfacing unless you have had a significant surface interval.
6) Green gas is good gas, use oxygen (at reasonable ppO2s) whenever needed.

Your spinal column will thank you.

The problem is not so much the recompression, but with decompression and recompression followed by a second decompression without first allowing enough time to adequately off-gas. Bubbles form/absorb more nitrogen during the first decompression, but the lungs do their job and prevent most of them from moving from the venous side to the arterial side where they can do damage. During the recompression, the bubbles are squashed down, so they can pass through the lung capillary filters. If someone subsequently decompresses again before those bubbles have a chance to dissipate, they re-expand through good old Boyle's Law, except now they're in the arterial side, with shrinking vein diameters and the potential to cause blockages.

It's less of an issue if you're doing a full-length deco stop after recompression. But I believe someone once commented that most of the time, you're talking tens of minutes, well beyond what most recreational NDL divers would consider a safety stop. Some food for thought: IIRC Doppler studies have found that for 'typical' NDL dives, detectable bubbles peak around 40-60 minutes into the SI, which would reinforce the suggestion that we're not talking a typical 3-5 minutes stop to avoid bubble pumping.

I read a difference being that one situation is ascending 'knowingly' without a safety stop, the other with an uncontrolled ascent, ie. a 'blown' SS. An uncontrolled ascent probably exceeds the recommended ascent rate of 10m/33ft per minute- especially in the last few meters which are thought to be the most important.

In an uncontrolled ascent, (with a probable fast ascent), all bets are off. Safety stops can be safely omitted only if correct ascent rates are maintained.

An uncontrolled ascent that substantially exceeds the ascent rate that is part of the decompression model, is not a "blown safety stop," rather, that is a "blown" decompression model. A blown safety stop (oxymoronic as the concept may be) is not making a planned safety stop whilst ascending at the prescribed rate, an irrelevant "infraction."

See also:
http://www.scubaboard.com/forums/ba...-safety-stop-immediately-after-surfacing.html
http://www.scubaboard.com/forums/ask-dr-decompression/278578-silent-bubbles.html

So a diver died because of a safety stop or low gas on a safety stop...? What, did he drown? I'm willing to bet there is far more to that story that what you included. Please provide the link.



Safety stops are not... Benign. Think about what you have said... "exposures involved in recreational dive profiles...boat dives in the ocean for example..." What or where is the comparison? What exposure are you talking about? Scuba diving in general, boat traffic, cold water, giant sharks, newbie divers? What are you talking about?
Better to get out of the water and possible exposure to ??? then stay and do a safety stop. That at the very least is an interesting point of view. I can say from experience that there have been a few times I skipped a safety stop to reduce my exposure to being cold in a drysuit having to pee, or spearfishing off florida coast and garnering the attention of a few blue sharks wanting my dinner which I handed over at the tip of my spear. Aside from a life threatening situation or serious discomfort I cant see any reason to plan on not making a safety stop.



I you plan and prepare properly, exposure would be reduced to start with. Taking all things into consideration, maybe the dive should be shorter so you can make that safety stop

Safety stops are being oversold by instructors who do not understand that they were invented not due to deco considerations but to slow the overall ascent (divers where typically doing 120 fpm when the accepted ascent rate was 60 fpm and to assure buoyancy control near the surface.

A few years back I got wrapped up with someone's student and an OOA situation. While the student used MY octo as the of us ascended, the student's INSTRUCTOR remained at 15' until his precious safety stop was complete. I'm fairly sure that the student ever broke 50' during the dive, and the OOA occurred at about 35'.

The instructor needs to be whipped. Not only was a safety stop NOT REALLY needed, but there was a real-life emergency and the instructor did nothing other than remain at 15' for a full three minutes while someone else took care of his student on the surface.

Yup, that instructot was real "farm animal stupid."

 

[Crush]

a danger of bubble pumping

Thal's definition of bubble pumping is good. Here is another article on bubble pumping by Doppler: http://www.scubaboard.com/forums/co...s-what-do-if-you-find-yourself-doing-one.html

 

[PfcAJ]

I think I heard it from Dr.Deco, and I think he might have had another name for it - altho one could call it whatever makes sense.

We call it surface deco. Not much value, imo, on rec dives.

 

[Adobo]

So a diver died because of a safety stop or low gas on a safety stop...? What, did he drown? I'm willing to bet there is far more to that story that what you included. Please provide the link.

There was more to it than that. But on of the errors the team committed was to do a safety stop when
one diver was critically low on gas. He wound up running out of gas before getting to the surface. Details available here:

http://www.scubaboard.com/forums/accidents-incidents/430827-fatality-off-point-lobos-california.html

Safety stops are not... Benign. Think about what you have said... "exposures involved in recreational dive profiles...boat dives in the ocean for example..." What or where is the comparison? What exposure are you talking about? Scuba diving in general, boat traffic, cold water, giant sharks, newbie divers? What are you talking about?
Better to get out of the water and possible exposure to ??? then stay and do a safety stop. That at the very least is an interesting point of view. I can say from experience that there have been a few times I skipped a safety stop to reduce my exposure to being cold in a drysuit having to pee, or spearfishing off florida coast and garnering the attention of a few blue sharks wanting my dinner which I handed over at the tip of my spear. Aside from a life threatening situation or serious discomfort I cant see any reason to plan on not making a safety stop.

I you plan and prepare properly, exposure would be reduced to start with. Taking all things into consideration, maybe the dive should be shorter so you can make that safety stop

I think you missed a few of the related replies prior to my post. In short:

- someone was talking about staying at the surface for 5-10 minutes after a dive. The idea being that avoiding strenuous activity immediately after a dive could further reduce the risk of DCS. Apparently, this is a practice that some cave divers observe.
- another person suggested that this could be viewed as some sort of best practice.
- I personally was commenting that while I do not see anything wrong with this practice, I find its benefits for recreational dives to be questionable at best. Further, this practice might be largely inconsequential in a spring but out in the ocean on a boat dive, things are a little bit different.

Now that I have clarified what I was referring to, if you have objections to what I have posted, please feel free to re-state.