runaway ascents, what to do?

[Jim Malone]

I have a reoccuring problem with buddies that seem to get into runaway ascents during our dives.
Because i am training to be a divemaster i frequently help out our instructor with new divers. On this dive two student divers did their 1st official O.W. dive. We formed buddy pairs. I decided to dive with the father who said he had done 5 dives in Egypt before and he seemed pretty confident about his diving capabilities.
We descended to 24 ft and the father seemed to have some trouble achieving bouyancy. After the excercises we did a little tour, and we slowly started to ascend. I watched the father pushing the deflate button but due to the fact that he was horizontal no air came out, so he started to float up towards the surface. I got closer and grabbed his fin and dumped my air to slow his ascend. His bouyancy was so high at this point he dragged the both of us up to the surface.
We missed a safety stop and had an ascend warning on my computer
He later told me that this dive in cold murky water was much more difficult then Egypt and that he tried to get air out of his BC but that he kept ascending.
I explained him why he had a runaway ascent, but i was wondering if my actions were correct. Should I leave a student shoot up to the surface or try to slow him/her down? What if a student under my supervision gets hurt and receives a lung barotrauma? What if we both get hurt?
Do any of you use a buddyline? This is quit a common tool here but i fear it might lead to more students dragging me up or down.
Should i have done anything else?

 

[Bubbletrubble]

I explained him why he had a runaway ascent, but i was wondering if my actions were correct. Should I leave a student shoot up to the surface or try to slow him/her down? What if a student under my supervision gets hurt and receives a lung barotrauma? What if we both get hurt?
Do any of you use a buddyline? This is quit a common tool here but i fear it might lead to more students dragging me up or down.
Should i have done anything else?

First of all, there's a difference between being a diver's buddy and working as a DM, i.e., watching over students during class dives or paid customers during guided tours. Your professional duties as a DM and concomitant legal/moral/ethical responsibilities should be made clear to you before you start working as a DM -- discuss this with the instructor providing your DM training. Right now, you are a DM-in-training. Technically, any students you "supervise" are actually being supervised by whomever is watching over you. Things change when you are a full-fledged DM.

Back to the given scenario...
The diver was your buddy. When your buddy is in trouble, you need to decide whether there is an acceptable level of risk for you to intervene. I think grabbing his fin and helping slow his ascent to a "safe" rate is well within the bounds of an acceptable amount of risk. If, at any time during the incident, your buddy + you began to ascend at an unsafe rate (and you can't dump any air from your BCD or your buddy's), one possible course of action would have been to simply let go of him, continue your ascent at a safe rate, and prepare to help out your buddy (in whatever condition he is in) at the surface.

One skill you'll develop as a DM is to head off minor issues before they become major ones. Your buddy revealed that he was a very inexperienced diver prior to the dive. Given this info, a seasoned dive pro would keep a very close eye on this diver...probably staying within arm's reach in case it was prudent to intervene, e.g., activate a dump valve, before a rapid, uncontrolled ascent was already occurring. The dive pro might also ensure that the novice diver is properly weighted for the dive (conduct a proper weight check), since over-weighting may make it more difficult for the diver to manage a safe ascent rate. Proper weighting is even more critical in a warm water diver who is diving in cold/temperate water for the first time because he won't be accustomed to wearing as much exposure protection (restrictive hood, thick suit, etc.) and having as much air in his BCD at depth. Such a scenario could make managing the larger BCD bubble and expansion of his neoprene during the ascent more challenging.

Once you become a full-fledged DM and are working with a student/customer, there is a duty to act...but bear in mind that you are never required to assume an "unacceptable level of risk" during a crisis situation. You would have to use judgment (based on your experience and training) to intervene at the appropriate time. There could certainly be a situation in which, despite trying to slow down your student/customer's ascent, the prudent thing for you to do is let go of him, surface at an accelerated but safe rate, and then follow emergency procedures to care for the diver at the surface.

In my locale, we deal with cold water and often low vis conditions (< 5 ft. vis). No one here uses a buddy line. It presents an entanglement hazard. If the vis is poor for only a certain segment of the dive, then we often proceed in a side-by-side fashion with a buddy (or establish touch contact if necessary). If the vis threatens to be poor for the entire dive, we usually make the decision to abort the dive altogether.

The practices in your area of the world seem to differ. If I had to use a buddy line, I would hold onto my end of the line in such a way that I could always release it if my buddy lost buoyancy control and experienced a dangerously rapid ascent. I would discuss this specific scenario with your instructor.

 

[BrianKon]

"Back to the given scenario...
The diver was your buddy. When your buddy is in trouble, you need to decide whether there is an acceptable level of risk for you to intervene. I think grabbing his fin and helping slow his ascent to a "safe" rate is well within the bounds of an acceptable amount of risk. If, at any time during the incident, your buddy + you began to ascend at an unsafe rate (and you can't dump any air from your BCD or your buddy's), one possible course of action would have been to simply let go of him, continue your ascent at a safe rate, and prepare to help out your buddy (in whatever condition he is in) at the surface."

Yes , this is the course of action to be taken

 

[TSandM]

If you are operating as a DM with OW students, you have accepted that you will bear an uneven amount of responsibility for the dive, as they are not even certified divers yet. In our cold, murky water, uncontrolled ascents are just downright common, as students are so overloaded with the temperature and the visibility that things they managed nicely in the pool are simply beyond them (like even remembering to vent their BCs!). When I am accompanying students, I like to have them buddy up and allow me to dive behind and slightly above them, which is an easy position from which to catch somebody who is beginning to float up. If I have to dive with one alone, I put him on my right and watch him like a hawk -- ANY sign of rising above me and he gets a light in the eyes and a hand signal to say "come down", at the same time I'm beginning to ascend myself -- if he doesn't act, I grab his rear dump and vent his BC myself (thus the reason for being on his left).

I have found that, if the student gets up enough of a head of steam, and given that student dives are always shallow, there is no way I can get negative enough to stop them, and all I can do is try to slow the ascent. This is particularly bad with students in dry suits, because although a buddy can vent your BC for you, NOBODY can vent your dry suit except you. The best I can do is try to make sure they're as vertical as possible, so the suit will auto-vent as much as it can.

As already stated, the most critical thing to do with students is to anticipate -- anticipate the trouble they are going to get into, and where they are going to get into it. It's not always possible, but in general, they'll do fine going downslope, and have trouble coming back up, and the shallower you get, the worse it is.

 

[Sinbad Scuba]

Buoyancy is the first skill introduced and the last skill mastered (if we ever really do!) As stated, anticipation is what is needed and it will come with practice. When I did open water instruction in a cold quarry, I normally held onto the bcd strap when a student was doing mask skills as that skill is what lead to bolting for the surface more than any other skill. The reason I held on to the BCD strap was so that as they bolted to the surface, my weight would slow them down enough so they would be forced to breath from their reg and not hold their breath. Most training dives are at a shallow enough depth that serious injury is not likely, though it is certainly possible.

Good buoyancy skills begin in the pool. I am shocked at the number of students that do not understand the concept of air goes up. I work this issue closely in the pool so students understand that to vent air, the vent must be the highest point. It is quite common for students to be horizontal, hold their deflator below them and try and vent air from their BCD. Fails every time.

A risk not mentioned with a bolting student is injury to you from an errant fin kick or being shoved away. You must be thoughtful and prepared to let the bolting/panicked student head for the surface on their own. The duty of care is defined as what another "prudent" DM would do. In other words, you do the best you can right up until you risk self-injury, then you stop and pray, follow the student to the surface and make sure they are OK. At that point, it might be time to call it a day.

 

[DevonDiver]

Step #1 - Help your divers get their weighting sorted out. Over-weighting is one of the primary issues leading to ascent control. Any excess weight translates directly to more air in the BCD. More air in the BCD leads to a proportionally greater expansion of air during the ascent - especially in those final 10m. 2lbs of excess lead equates roughly to a lite of air in the BCD. Every extra lb of surplus lead makes buoyancy control proportionally more difficult. Tackle the root of the problem (weighting) and you might not have such difficulty having to deal with the symptoms (uncontrolled ascents).

For a diver to drag both themselves and you to the surface would require a huge amount of surplus buoyancy. That is only likely to happen in 2 circumstances; either they have an LPI stick or they are overweighted massively...leading to a huge volume of air in their BCDs at depth, which then expands enormously as they ascend. A properly weighted diver should have a virtually empty BCD at depth... with only enough air to compensate for exposure suit compression. That amount of air should never be enough to drag one or more divers to the surface!

Step #2 - Practice grabbing an ascending diver and dumping their BCD. This is something that should be more reinforced on rescue and DM courses. Whilst doing so, make sure to 'flair' your body to reduce ascent speed through adding water resistance. Get slick with this maneouvre. You have to apply it quickly, before ascent/expansion becomes uncontrollable.

It's tempting to consider over-weighting yourself to help deal with scenarios like this - but doing so can actually add to your problems. If you are over-weighted also, then any intial ascent whilst dealing with another divers' problem is going to lead to massive buoyancy gain in your own BCD... after a short ascent, you'll have two buoyancy issues to deal with... the original one, plus your own.

Step #3 - Establish your own boundaries of risk. As a DM (with qualified divers) you are not responsible for their safety in this respect. However, you may feel that you have a moral obligation to protect them. You have to balance that against your own personal risk... bear in mind your recent dive history when deciding whether to allow yourself to be dragged to the surface. It's a bit different with trainee/unqualified divers... but then again, the instructor bears that responsibility...and should have accounted for this when planning the training. As a trainee divemaster you have no obligation or responsibility to do this. The instructor should brief you on what is expected.

Buddy Lines? No way! If you get injured in the incident, you are then unable to render assistance to the casualty. Worse than that... you add a further burden to the other rescuers. A buddy line is a good idea for certain scenarios.... for example, low visibility. It shouldn't be used as a 'leash' for incompetant divers.

 

[TSandM]

Andy, I DO overweight myself by several pounds when diving with students -- but I use my dry suit for buoyancy, so it's pretty easy for me to dump air while grabbing a student and dumping their BC as well. For that reason, I really liked diving doubles with students, because I could get very negative very quickly -- but that was offset by not being nearly as nimble in the water, so I went back to big single tanks instead, and just added a bit of weight.

I will also mildly disagree that a properly weighted student can't drag you to the surface -- in Puget Sound, with the thickness of neoprene that we have to use on our students, or even worse, with the ones in dry suits -- they can! We spend quite a bit of time trying to get folks properly weighted, but they can still get positive enough that I can't stop them, if they move up far enough in the water column. There just isn't enough time in the water column on these shallow OW checkout dives to be able to do very much, if they get rolling. That's why anticipation is so important. If you can catch them when they're only a foot or two off depth, they're easy to stop. More than that, and it gets challenging.

 

[mikemill]

This is particularly bad with students in dry suits, because although a buddy can vent your BC for you, NOBODY can vent your dry suit except you. The best I can do is try to make sure they're as vertical as possible, so the suit will auto-vent as much as it can.

Try pushing the vent as some (all?) will exhaust easier (take less pressure delta) when doing so. And you can give it a turn to make sure it is all the way open. If you feel really mean (and got them vertical) you can try and get in under their hood and pop their neck seal though that might not be too feasible if you are using dry gloves. Added bonus that they get wet to remind them they did bad

 

[DevonDiver]

There just isn't enough time in the water column on these shallow OW checkout dives to be able to do very much, if they get rolling. That's why anticipation is so important. If you can catch them when they're only a foot or two off depth, they're easy to stop. More than that, and it gets challenging.

Hit the nail on the head. Prevention is better than cure. A dive pro, dealing with trainee divers, shouldn't be in a position where they couldn't anticipate and prevent this problem before it became uncontrollable.

 

[Krazytomdiver]

As a dive guide,I do not work with students but I do dive with very inexperienced divers(?). Experinence by reconizing & anticipitating a situation is key to the customer's safety. I am usually 4lbs/2kilos overweighted on each dive so grabbing the out-of-control diver's top BCD air dump,(there's no air in my BCD),turn us both downward & fin, usually works. If not at least I slow them down enough that injury is minimal. I NEVER put myself in any kind of danger what so ever at anytime. IMPO I would allow a wantabe DM to be responsible for any of my customers safety by complicating/interferring. This would be stated in my dive brief.

"living life without a hard bottom"
KT