Lost sight of buddies - tank came loose

[DevonDiver]

Kit remove and replace is a core open water skill. It can achieved using integrated weights, but yes, it takes practice to adapt the skill.

Aren't divers told that they should keep their skills refreshed and applicable to the kit they use?

I agree completely that the cause of the problem was a failure of the buddy system. The tank strap should have been checked pre-dive. The buddy should have had awareness during the dive...and anticipated the problem as he saw it slipping etc

However, the failure to resolve the incident immediately (at depth), was due to poor skills by the diver concerned. This was because he had changed configurations and did not attempt to refresh his skills so that they would be appropriate to the new equipment.

 

[John C. Ratliff]

Have you ever actually tried it?

I demo this a few times a week in a WI BC and can tell you quite definitively, it's not difficult or complicated, and students who have only been in the pool for four sessions do pretty good the first time they see it.

If You + WI BC are neutral, when you take your arms out of the arm holes, you + WI BC are still neutral.

The BC tends to sink and you tend to float, however as long as you don't let go, you're still neutral

It doesn't fly away, nothing gets ripped out of your mouth, and in reality, once you get over the shock of being underwater staring at your BC instead of wearing it, it's pretty much a snooze.

In the case of a loose tank strap, all that's required is to tighten it up a little and re-fasten the tank.

flots

I'm sure you do take your BC off with the scuba attached; I'm also pretty sure you don't allow your scuba tank to separate from the BC prior to taking it off underwater. Here's what the OP said:

However during this situation I felt a continual bumping from behind and I kept turning round and there was nothing there - became anxious - and I realised my tank had loosened from the velcro and was hanging on its own without support.

I stayed down and completed my safety stop and ascended and everything was cool though when I was on the surface it was obvious my tank was just free of my BCD and I had to be helped.

This diver was concerned that the regulator could become separated from the tank valve while in use; that was dispelled pages ago. But next time you do this demo in open water, have one of your students release the tank from the BC. I'm sure you'll handle it just fine, as you will know about it and have pre-planned it in your head. This diver did not have that luxury. Also, be sure to do it in open water, say 20 feet above the bottom; don't use the bottom as a crutch (quite literally). Then, pull the scuba tank back through the loop of velcro for the tank strap, and secure it. Once that is accomplished, put it back on. It is not a difficult task, but tell me this, do you practice this with the tank out of the BC underwater during this exercise?

SeaRat

 

[DevonDiver]

Every scuba incident consists of a chain of events. If unbroken, that chain leads to disaster. They key to avoiding incidents, is to ensure that your procedures and skills prevent the chain from occuring at the earliest stage.

Let's analyise this chain..

1) Pre-Dive Equipment Assembly. Equipment was not put together by the diver. If the diver had insisted on assembling and checking his equipment at this stage, the problem may have been identified and rectified, or never occured in the first place.

2) Pre-Dive Safety/Buddy Check. The pre-dive buddy check should include all straps and releases, including the cylinder cam-band. If conducted properly, the check should have identified the problem and allowed rectification before the divers entered the water.

3) Buddy Skills - Water entry and Descent. Proper buddy skills should dictate an awareness of the buddy, especially during the descent phase. It is likely that the cylinder began to slip during/after water entry. If the dive pair had maintained close contact during the water entry and descent, there is a likelihood that the problem could have been identified and rectified before the tank had fully disengaged from the cam-band. It is a good procedure to pause the descent at 5m, to conduct a brief visual check of your buddy and their equipment.

4) Buddy Skills - Dive. Again, proper buddy skills would have ensured that the problem would be identified immediately by the diver's partner. They should have identified and rectified the problem as soon as it became apparent. At no point, should the diver have been left unattended.

5) Self-Rescue Skills. The diver should have been familiar and practised with their equipment, possessing the skills and confidence to resolve the problem immediately.

6) Dive Plan. The diver should not have been left alone because the group decided to enter a restricted area (swim-through). The decision to enter a restricted area should have been communicated as part of the dive briefing. This would have allowed contingency planning and personal decision making/risk assessment to be conducted prior to the dive itself. If the buddy team were aware of this issue within the dive plan, then they would have a pre-established system to complete that phase of the dive.

7) Solo Ascent. The dive group should have noticed that the diver had not followed through the restriction. There should have been supervision at the front and end of the dive group when going through the restriction. The dive leader and/or buddy should have returned immediately to the diver when they did not follow. This caused a solo ascent. If the diving conditions had been different, then this could easily have added further 'chain' to the incident. For example, strong current could move the diver away from surface support. Bad visibility could see the diver get disorientated on ascent. etc

8) Surface Rectification. The diver safely ascended and was assisted to resolve the problem. This represents the 'end of the incident chain'. This is primarily because no other factors occured that added more 'links' to the chain. However, if the chain had continued, the situation could have become more serious...

9) Chain Continued (Hypothetical).

a) Diver loses air during ascent.
b) Diver panics on ascent.
c) No surface support available on the surface.
d) Diver cannot attain positive buoyancy on the surface.
e) Diver carried by current on ascent.
f) Diver disorientated by visibility on ascent.

In this instance, the 'chain' was not broken until the 8th stage. This was because no other factors presented themselves to continue the chain.

 

[TSandM]

BEAUTIFUL post and analysis, Andy!

 

[flots am]

The point is that you are advocating a diver, untrained in this procedure, should try this @ 50' mid water in new gear for the first time during his first unintentional solo dive, Maybe its just me.

This is a basic SCUBA skill. Why would anybody be "untrained"?

flots.

 

[Bob DBF]

At the point of the incident it makes no difference why.



Bob
------------------------------
I may be old, but I’m not dead yet.

"the future is uncertain and the end is always near"
Jim Morrison

 

[flots am]

I'm sure you do take your BC off with the scuba attached; I'm also pretty sure you don't allow your scuba tank to separate from the BC prior to taking it off underwater.

It's a little difficult to simply "will" the tank off the BC while wearing it underwater, however I do demonstrate removing the BC, disconnecting the tank strap, adjusting it and reattaching it while neutral. Considering that "loose tank" is one of the most common underwater problems, I can't imagine that anybody would do a class and not cover this.

I also make sure that everybody knows that this won't be necessary if they tighten the tank strap properly before entering the water.

flots.

 

[DevonDiver]

I include this scenario (slipped tank) in my Rescue courses. It's pretty common, I've lost count of the times I've assisted a diver with a slipped tank.

 

[John C. Ratliff]

I include this scenario (slipped tank) in my Rescue courses. It's pretty common, I've lost count of the times I've assisted a diver with a slipped tank.

You realize that you have identified a product safety issue that DEMA should address with industry standards. I am old enough (turning 65 in a week) and far enough back (started diving in 1959) to say that this did not happen in the older days of diving. But it is no coincident that DEMA changed its name from the Diving Equipment Manufacturer's Association to the Diving Equipment and Marketing Association. It has no teeth, so we get manufacturers who make products which can easily (apparently) have this "slipped tank" problem. Not only did this not happen in the past, it could not happen in the past. We had medal bands which took a wrench to take off holding the tank to the harness.

I do not dive current equipment; I am a vintage diver, and can say that this type of incident cannot occur with any equipment that I currently own.

So rather than talking about how the diver should cope with this through training, we should be figuring out why the diving industry has allowed this to occur, and put into place a root causes analysis with action items which will preclude it from happening in the future.

Concerning training, when we look at the Hierarchy of Controls for incident prevention, these are administrative controls and PPE (personal protective equipment). This is the lowest in priority in the Hierarchy of Controls, meaning that they are the least effective. This is actually shown in this particular incident to be true too. We need to be looking at engineering controls, and substitution. Why do we allow a Velcro attachment prone to failure on a piece of life support equipment? Take a look at the photos below from my Pararescue days; can you imagine what could have happened if a "tank slipped" during a parascuba jump?

In the semiconductor business, we go through a process of accident analysis which we call the "Five Whys" process; it can be applied to any accident/incident situation. Basically, start asking "why" five times, in three different areas

The Incident
1. Why did he have to surface? His tanks slipped.
2. Why did the tank slip? Because it was not checked correctly prior to the dive.
3. Why was it not checked? Because the dive charter hurried through the pre-dive process.
4. Why did the dive charter hurry through the pre-dive process? Unknown, needs further investigation.
5. Why did the diver not check his/her gear? Because the authority, the boat dive master, encouraged them not to.

The Process
1. Why did the process allow this to happen? It was considered "norm" for this boat.
2. Why did the buddies not see the problem, and conduct routine buddy checks? This goes back to the charter and the dive master. They set the "culture" for the dive.
3. Why did the diver allow this dive master to set this kind of culture? Because the diver was new, and not very well trained in his basic course (apparently).
4. Why could the diver/buddy not handle this situation underwater? The buddy system broke down with the excitement of the exploration, and the buddy system went away. This became a group dive with no one watching out for the other guy.
5. Why was this not covered in the diver's training? Unknown.

The Equipment
1. Why did the tank slip? Because the Velcro was not tight.
2. Why was the Velcro attachment not tight? Because the diver, the dive master, the dive equipment maintenance person, all missed checking the attachment.
3. Why was this type of attachment allowed to be used in a life support system? It has become "normal" in the dive industry so that it is convenient to change tanks quickly.
4. Why is there no "fail-safe" mode for this attachment? It was not designed in at the manufacturer's level.
5. Why is this kind of oversight allowed within the diving industry? There apparently are no industry standards for the diving industry, such as is seen in other industries (SEMI being notable here).

From this information, Action Items can be developed with assigned personnel, dates, etc. to implement changes.

There is one other point to be made here. Many people who dive now do not consider surfacing a viable option due to their orientation to "overhead environments" (an older term we used in the 1980s to define any diving situation where we could not surface for some reason). Technical divers dive in a manner to assume an overhead environment, either by going through/under obstructions (caves and caverns), wreck diving, ice diving, or deep diving with decompression (where nitrogen loading precludes a direct ascent to the surface). These used to be considered specialty diving, but more and more are becoming the norm. But surfacing is a viable option in many (if not most) diving situations which used to be considered "normal" to diving (no decompression diving, for instance).

SeaRat

 

[underthedeepblue]

Every scuba incident consists of a chain of events. If unbroken, that chain leads to disaster. They key to avoiding incidents, is to ensure that your procedures and skills prevent the chain from occuring at the earliest stage.

Let's analyise this chain..

1) Pre-Dive Equipment Assembly. Equipment was not put together by the diver. If the diver had insisted on assembling and checking his equipment at this stage, the problem may have been identified and rectified, or never occured in the first place.

2) Pre-Dive Safety/Buddy Check. The pre-dive buddy check should include all straps and releases, including the cylinder cam-band. If conducted properly, the check should have identified the problem and allowed rectification before the divers entered the water.

3) Buddy Skills - Water entry and Descent. Proper buddy skills should dictate an awareness of the buddy, especially during the descent phase. It is likely that the cylinder began to slip during/after water entry. If the dive pair had maintained close contact during the water entry and descent, there is a likelihood that the problem could have been identified and rectified before the tank had fully disengaged from the cam-band. It is a good procedure to pause the descent at 5m, to conduct a brief visual check of your buddy and their equipment.

4) Buddy Skills - Dive. Again, proper buddy skills would have ensured that the problem would be identified immediately by the diver's partner. They should have identified and rectified the problem as soon as it became apparent. At no point, should the diver have been left unattended.

5) Self-Rescue Skills. The diver should have been familiar and practised with their equipment, possessing the skills and confidence to resolve the problem immediately.

6) Dive Plan. The diver should not have been left alone because the group decided to enter a restricted area (swim-through). The decision to enter a restricted area should have been communicated as part of the dive briefing. This would have allowed contingency planning and personal decision making/risk assessment to be conducted prior to the dive itself. If the buddy team were aware of this issue within the dive plan, then they would have a pre-established system to complete that phase of the dive.

7) Solo Ascent. The dive group should have noticed that the diver had not followed through the restriction. There should have been supervision at the front and end of the dive group when going through the restriction. The dive leader and/or buddy should have returned immediately to the diver when they did not follow. This caused a solo ascent. If the diving conditions had been different, then this could easily have added further 'chain' to the incident. For example, strong current could move the diver away from surface support. Bad visibility could see the diver get disorientated on ascent. etc

8) Surface Rectification. The diver safely ascended and was assisted to resolve the problem. This represents the 'end of the incident chain'. This is primarily because no other factors occured that added more 'links' to the chain. However, if the chain had continued, the situation could have become more serious...

9) Chain Continued (Hypothetical).

a) Diver loses air during ascent.
b) Diver panics on ascent.
c) No surface support available on the surface.
d) Diver cannot attain positive buoyancy on the surface.
e) Diver carried by current on ascent.
f) Diver disorientated by visibility on ascent.

In this instance, the 'chain' was not broken until the 8th stage. This was because no other factors presented themselves to continue the chain.[/QUOTE

I am the Original Poster of this issue and your first sentence is exactly correct. There were a chain of events that could have ended up with me dead and I am not going to dive again until I work it out.

I was basically too shy to insist on safety because I was on my own and was embarrassed to take control. There were other issues too. The dive master was cavalier and I was too stupid to check my equipment.
Never again.

I came back into this forum today because I honestly think I couldn't think about it until now.

Had one more thing gone wrong I may have drowned. I am astonished I didn't panic