What if miss a required safety stop?

[northernone]

The line needed drawn somewhere safe enough to avoid some lawsuits.

Individual factors such as fitness, hydration and medical history give us each a real NDL, what time depth and ascent profile (rate, stops if you like) which keep us safe and varies from dive to dive. Sadly charts, computers or raw antidotal experience can not allowed us to calculate this.

Thoughtful question.


Regards,
Cameron

Note: recreational maximum depth is 40 metres (130 ft) according to padi.

 

[AJ]

Though I don't think there'd be an issue, I am a conservative diver so I would likely not dive for 24 hours afterwards.

What if your computer does not do safety stops like Shearwater Petrel 1? Am I in violation or can I dive again that day? Furthermore, on several occasions different computers gave different advice on safety stops in my teams. What to do then?

I prefer to base my descion on tables, knowledge and agreed deco strategy within my team. Not relying on computers with very different often unknown algorithm's. So would I be worried if my computer complains about a missed safety stop? Nope, I have a plan when I dive.

 

[JohnnyC]

This is sort of where the fallacy of conservatism comes into play (liberal vs conservative computer algorithms, tables, etc.). Your personal level of DCS is entirely independent from what a computer or a table says it should be. You may require a much more conservative profile in order to prevent DCS, or you may be able to exceed "NDL's" without issue. In the second case, the NDL clearly isn't, and your NDL for a 30m dive may be completely different from someone else's.

What PADI has done is exactly what boulderjohn says, and you need to decide if you want to play in their sandbox or not. What will happen, and what you should do, is entirely dependent on your own personal physiology. If you are prone to DCS, missing that safety stop could be an issue, and really, since that line-in-the-sand may change day-to-day and dive-to-dive, there's really no good way to give any sort of definitive answer other than "err on the side of caution."

Now, to make the issue even more confusing, Mark Powell, in his book "Deco for Divers," which I highly recommend EVERY diver reading, quotes a study where divers were tested post dive after following different ascent profiles during recreational dives within the NDL's. What they found was that from varying stops lengths from no stops, one stop of x time, one stop of y time, and stages stops of z time, had dramatically decreasing levels of post-dive bubble formation the longer the divers spent on their safety stops. If you believe that bubbles are a positive indicator of DCS risk (which empirically seems to be the case), then the divers with no stop were more likely to get bent than the x safety stop group. They were more likely to get bent than the y safety stop group, who were more likely to get bent than the staged stop z group.

Ultimately what it tells us is that if you want to lower your risk, even within NDL dives, that a staged ascent profile is the least likely to cause bubbles, which are a positive indicator of DCS, and that a direct ascent with no stop is the most likely to cause bubbles.

So herein lies the rub, if you skip the safety stop, will you get bent? The answer is that we don't know. Maybe, maybe not? It's not something I would want to empirically test, when it's less stressful to just do the stops. IF I had made a direct ascent, I'd take a looooooong SIT and reevaluated before splashing, in which case I'd do a shallow dive well within whatever NDL's I was using.

 

[NYCNaiad]

What if your computer does not do safety stops like Shearwater Petrel 1? Am I in violation or can I dive again that day? Furthermore, on several occasions different computers gave different advice on safety stops in my teams. What to do then?...

My computer does safety stops. Planning your dive, you & your buddies generally know if one of your computers is more conservative than the others. But even if you don't, my personal rule of thumb is to follow the more conservative computer. It never hurts to err on the side of safety.

...I prefer to base my descion on tables, knowledge and agreed deco strategy within my team. Not relying on computers with very different often unknown algorithm's. So would I be worried if my computer complains about a missed safety stop? Nope, I have a plan when I dive.

I agree with you that knowledge & an agreed upon strategy are important. However, tables have some pretty significant limitations including the fact that they don't actually match your dive real-time which a computer can do. If you're going to ignore your computer, why even use one then?

 

[nohappy]

Hi guys,
I appreciate all your answers, but my question is not "will I get bend if I missed a required safety stop?". My question is that since PADI says it's a required safety stop after 30m or deeper dive, what should I respond if I missed it? Let's not focus on the possibility of getting bend if I missed a safety stop. PADI says we should not dive in the next 24hr if you missed a "deco stop" (and a deco stop is mandatory). I only wonder if there is any study or reliable paper or PADI itself told us what to do next (since it says it's a required safety stop).

To sum up, my question should be "if it's a required thing, what to do next if I didn't do it? If it's OK to continue diving, why do you call it "required" but not "highly recommend?".
So far, I couldn't find any discussion or paper about this.

NOTE.
I also know that I shouldn't enter deco of course, just making an example.

 

[NYCNaiad]

Hi guys,
I appreciate all your answers, but my question is not "will I get bend if I missed a required safety stop?". My question is that since PADI says it's a required safety stop after 30m or deeper dive, what should I respond if I missed it? Let's not focus on the possibility of getting bend if I missed a safety stop. PADI says we should not dive in the next 24hr if you missed a "deco stop" (and a deco stop is mandatory). I only wonder if there is any study or reliable paper or PADI itself told us what to do next (since it says it's a required safety stop).

So far, I couldn't find any discussion or paper about this.

NOTE.
I also know that I shouldn't enter deco of course, just making an example.

I believe PADI notes that you shouldn't dive for 24 hours, but I don't have easy access to the PADI course material so I may be wrong. However, a lot of this is a gray area which is why you got the answers you did. As with a number of things in diving, the correct answer is dependent upon how you dive, your health & the choices you make.

• Some of us noted we would not dive and/or would significantly alter our diving for 24 hours. (I'm in that group of conservative divers.)
• Others said they would keep an eye on themselves for symptoms, but still dive.
• Some said they wouldn't be bothered if they missed the stop (& this wouldn't change their diving at all).

You will have to decide what makes the best sense for you.

Personally, I think it's always better to be safe than sorry so I usually err on the side of caution. This means I occasionally miss out on something good, but it also means I generally have a higher cushion of safety.

 

[yle]

I believe PADI notes that you shouldn't dive for 24 hours,

PADI's RDP addresses safety stops and emergency deco stops. The latter are required if you exceed your NDL. And the "no diving for 24 hours" on the RDP is for the emergency deco stop, not for a missed safety stop.

To the OP... you should be aware that making a safety stop does not guarantee you'll be free from DCS, and missing a safety stop does not much increase your risk of DCS. As a new diver, I would recommend you always pay close attention to your ascent rate; slow ascent rates are far more important than safety stops to keeping your DCS risk low, but are frequently ignored by new divers (and even old divers.)

 

[KevinNM]

Safety stops are not mandatory stops, they are recommendations. Presumably you had some good reason to do a direct ascent, right? I'd just be a bit more conservative on the next dive and do the safety stop. If you just blew though it for no reason that is an issue to correct, because that probably means you had an excessive ascent rate which implies a major buoyancy issue. You should be able to stop at any depth along your ascent and hold that stop within a few feet for a few minutes. If you can't stop at the 10 to 15 foot depth for a safety stop you either don't have enough lead or you are not controlling the air in your BCD.

 

[JohnnyC]

If you can't stop at the 10 to 15 foot depth for a safety stop you either don't have enough lead or you are not controlling the air in your BCD.

Or OOG in which case bent is better than drowned. One is generally easier to fix than the other.



OP, my answer was pretty verbose because it's a very gray area, and why I specifically mentioned you need to decide if you want to follow PADI's directions. If you want to follow PADI's direction, then 1) why are you missing your emergency decompression stop in the first place, and 2) why are you putting yourself in a situation where the possibility even arises. If it's "required," it's a deco stop, not a "safety stop." Their own language throws a wrench in it.

See how it's a gray area? Which is why you need to take a good long look at the whole issue, and not blindly trying to follow along.

To reiterate what I would do, I'd take an extra long surface interval and reevaluate close to splash time, and change my profile to shallow and well within the NDL scheme that I was using.

 

[AJ]

However, tables have some pretty significant limitations including the fact that they don't actually match your dive real-time which a computer can do. If you're going to ignore your computer, why even use one then?

I use a strategy that's more conservative than most computers (GUE deco strategy). Therefore I don't care much about what any computer might say, I just follow this strategy because I consider it safe and easy to execute on the fly within a team. I use my computer to know depth and time. Those two are really important to me, not very interested in warnings about stops. I know where and when to stop because whe decided on forehand. Shearwater does a great job at that. It is a reliable advisor, not a deco boss.

To answer the question from the OP: it depends on what or who you trust. But choose one method/opinion within your team and stick with it. If you trust your computer, go for it. If you trust PADI or GUE or IANTD or ....whatever, no problem. But choose a strategy that's decisive and clear to all team members. Relying on some computer without understanding what it tells you and why can be dangerous. It may come to the point that you have to decide between out of air of violating a stop. Not good, a plan within the team is better.

The suggestion to read Mark Powells book is a very good suggestion. After reading that book tables, computer algorithms, GF, etc. made really sense to me. I comprehended deco theory way beyond what's educated in a PADI, SSI or even Tech courses. IMHO this maybe the best answer TS might get.