Discussion topic - buddy separation protocol

[bleeb]

Here's question that I think is relevant.
I am under the understanding that descending to do a "safety stop" after spending a few minutes on the surface is not harmful but beneficial. True ?

I'm no expert, but my understanding is that redescending only for a missed safety stop may cause more problems than it solves, especially if there's already any significant nitrogen load. The lungs normally act as a pretty good bubble filter, and redescending can recompress a bubble, making it small enough to pass through the filter from the venous side to the arterial side of the circulatory system, where it can cause much more damage when you later reascend and it re-expands. Sort of the same reason, or at least one of them, why sawtooth and reverse profiles aren't recommended. I think this is sometimes known as 'bubble pumping'. Now if you have another reason to go back down, it may be an acceptable risk for you, but that's a separate issue.

 

[LeadTurn_SD]

Here's question that I think is relevant.
I am under the understanding that descending to do a "safety stop" after spending a few minutes on the surface is not harmful but beneficial. True ?
I would typically descend again to 15-20ft if contact was not made on the surface after a few minutes and head for the boat. :depressed:

Let me answer in a round-about way:

1.) I'd be very reluctant to descend back to the bottom to look for the missing diver after surfacing from a deep dive (even if I did the "safety stop"). Significant DCS risk.... you face the risk of pushing any micro-bubbles that may be present from the venous to the arterial side, not a good thing.... But I would take the risk if I believed they were still down there and I had even a remote chance of helping them.... you see, my dive buddies are my wife and kids. Not searching for them is just not an option for me.

2.) My understanding (and hopefully others will chime in and correct this if I'm wrong) is that "in-water" recompression to make up for a missed stop is usually not recommended. Once you have surfaced, stay surfaced, and get on oxygen if you think you are at risk of a DCS hit.... Again, if we are simply talking about a missed "safety stop" and you were within NDL, you are probably just fine. Many of us dove for years without any stinkin' "safety stops" and surfacing at 60 feet per minute when within NDL limits.

 

[DA Aquamaster]

I know when I took OW and AOW in 1985, PADI taught missed deco procedures whihc was basically to:

1. Redescend within 5 minutes.
2. go to 40' for 1/4 the 10' stop
3. go to 30' for 1/3rd the 10' stop
4. go to 20' for 1/2 the 10' stop
5. go to 10' for 1.5 times the 10' stop

This was based on the US Navy missed deco protocol of the time (and we still used the PADI version of the US Navy tables, complete with deco stops for all dives to 140' or less with times requiring deco stops no deeper than 10'). Since then the US Navy has modified their protocol to include O2 use and recreational agencies ran screaming from the idea.

The current opinion now is to stay on the boat and breathe O2 and if it were a case of missing a few minutes of deco at the 10' stop (possibly still being within the olde US Navy NDL's) I'd just stay on the boat and breathe O2. I think that is the most prudent approach for the average recreational diver.

On the other hand, if I missed a lot of deco on a technical dive (which by the way I would not in the first place), I'd probably be inclined to go back down and do in water recompression. Helicopters historically seem to take hours to get to you to evacuate you with another hour or two to get you to a chamber that most likley can't blow you down below 165' and consequently would not do a great job of eliminating all the bubbles that formed during the several hours since you surfaced.

 

[bogiewan]

Of course, I am speaking of a missed safety stop, NOT a deco stop. - and I am talking about just a few minutes on the surface.

This is similar to a situation where you might need to surface to locate the boat and re-descend.
I can't see any reason that the more time you can spend at 15-20ft wouldn't be a beneficial thing, even after a very short surface time. You wouldn't be going for in water deco, which is problematic because of the time it takes, but simply allowing a little more safety margin at a depth that can allow off gassing without incurring any deco load.

Honestly, sometimes I think the buddy system is a bit over stressed.
I think every diver should understand his buddy probably will be little or no help in case of trouble and accept that as a risk of the sport. You are ultimately responsible for your own safety.

I usually dive in low or limited viz conditions where separations are commonplace even with the best of intentions.
I really try to buddy with someone who's skills I'm familiar with. That usually includes an understanding that we really are diving solo, even with a buddy. We try to stay together as much as possible but occasionally separation happens. Of course, we make an effort to find each other but if that doesn't happen within a few minutes, we simply continue the dive. All divers should be responsible for their own navigational and safety skills and should be able to get back home on their own. If they can't do that, they probably shouldn't be out there to begin with.

Stand by for the flaming !

 

[TSandM]

I think every diver should understand his buddy probably will be little or no help in case of trouble and accept that as a risk of the sport. You are ultimately responsible for your own safety.

Every diver is ultimately responsible for his own safety -- I would completely agree with that. And every diver should have the skills to execute the proposed dive and to abort it alone, if need be. However, I disagree that one should not expect help from a buddy. If divers are well trained and practiced, they can be a great deal of help to one another, in circumstance ranging from disconnected hoses to running out of gas. If a buddy were never helpful, why do so many people expect so much from divemasters?

I dive in a strange and small subset of the diving world. In my world, staying together as a team is the most central and primary focus of a dive, so we almost never get separated, even in very poor viz and difficult water conditions. We also practice basic diving skills AND emergency procedures, so that the buddy you haven't lost is also well prepared to be of assistance, and has the control to handle helping you AND maintaining control of his own dive.

I understand the attitude that a buddy is at best a convenience and at worst a liability, but I deplore it. It doesn't have to be that way. In my world, it isn't.

 

[macado]

I find the answer depends where and who I am diving with. The first thing I always do is discuss lost buddy procedures before any dive that way everyone is on the same page.

Often times if I am lobster diving or scalloping we will most likely become separated anyway. At this point it becomes a solo dive however we would have discussed this in advance. A lot of dives in New England (for me at least) end up becoming solo dives with the risk that me and my buddy ultimately accept (and discuss beforehand).

If the plan was to stay together and I am carrying a flag (shore dive) and we get separated we will both look for a few minutes and then surface near the flag.

I know the OP said if a safety stop was required. If it's a true safety stop (E.G., not a deco stop) then I will skip it and surface. If I incurred any deco time (usually unlikely as I am not deco trained) or I want to do a safety stop then I will shoot an SMB and continue my safety stop and then surface.

 

[copter53]

I would just continue the dive solo. You can't piss your pants every time you lose your buddy. You have to know how to operate on your own when it becomes necessary.

 

[Bob DBF]

To put my perspective on this and add a bit more history to DA Auamaster's post.

Until I got a computer which was fairly recently, I dove tables from back when. As I was having disagreements with the computer I started checking out the "new diving" and doing some reading and so on. Times and diving have changed a bit.

1. The dive tables (and computers) have been changed to reduce bottom time at depth, 55min@60' from 60min@60'.
2. The ascent rate has been cut in half, 30fpm from 60fpm.
3. A 3min safety stop at 15' has been instituted. It is implied and/or taught to be mandatory
This increases safety but without understanding of the changes.

Why anyone would consider a safety stop when they may be faced with an emergency astounds me. Granted, it assumed you are taking diving as buddies seriously, which should be worked out before you hit the water.

 

[Ardy]

I think it all depends on the situation as a couple of you have stated before.

You never know how you will act until you are into it.

I think that this is the correct thing to do, planning for it is and discussing it is useful but at the time some may say 'bugger it! let them look after themselves' and others will go straight back down and look for them. It very much depends on how well you know them and as I rarely know my dive buddies it will very much depend on how I act at the time.

I have had the unpleasant experience of bailing out inexperienced divers and I don't want to repeat that.