Dropped weight belt

[DevonDiver]

You can't put an extra 10 lb weight belt on and just ascend normally? Why mess with a liftbag for 2 5 lb weights?

It's kind of right on the limit - as per the PADI Search and Recovery...

Q6. Explain why you should never use your BCD for lifting objects.
Excess buoyancy could cause a runaway ascent if object is dropped or breaks free.


Q7. Identify the weight at which use of a lift bag becomes mandatory.
4 kilograms/10 pounds

A risk assessment, coupled with professional knowledge, should have identified the hazards involved with the recovery. As instructors, we get used to conducting risk assessments when dealing with students. Sometimes complacency sets in and we forget to do them for ourselves...

 

[Quero]

While I guess anything is possible, and yes, you should have thought through the dive plan before doing a bounce dive to retrieve the dropped weights (to decide, for example, the maximum depth you would go for your search, the maximum time you would spend on the search, whether you had sufficient air for the dive, how the dive would impact your subsequent dives on the same day, etc.), in fact, if you had made a plan, and carried it out, you would have figured out you could do this dive with very little risk other than some catastrophic failure.

If you had decided, for example, that you would dive to a maximum depth of 35 meters, and in doing a dive plan you found that your NDL was 13 minutes, then that would have been the basis of your planning. On top of that, you'd need to calculate your air reserves, but as an instructor, I imagine that your RMV is pretty good. Mine is about 12 litres a minute on average, so at a depth of 4.5 ata, my tank would last me about 40 minutes; I should have plenty of air for a 13 minute bounce dive. As long as I had a spare tank on the boat to switch out and my AOW training dive was going to be something not too deep (like navigation), I might have gone down for the belt/weights.

Now as for considering a catastrophic loss of all your breathing gas at depth and not having a buddy to provide a redundant air supply, yeah, it could have happened. The chance of it happening would seem to be rather small, but still.... If you think you are going to be in a position to have to do some solo dives like this in the future, I would recommend that you find out about self-sufficiency in diving. There are courses you can take, or you can get some mentoring from somebody who is meticulous about planning solo dives.

So from this incident you can perhaps learn that
1) you need to plan your dives, even bounce dives like the one you did, so that you don't think about a bunch of "what if's" after the fact ("what if" thinking should be done beforehand with the aim of preventing mishaps)
2) you need to have spare equipment with you on all dive outings, including equipment (e.g., a stage tank) for the possibility of having to do a solo dive when you've got no DM with you to help out.

 

[Hatul]

Location: Dayang
Date: 9th March 2013

I was teaching AOW when my last student to do the giant stride in dropped his weight belt.
As this was their very first dive of the day/course and we didnt have any spare weights on the boat I made them all huddle in a group and went down solo (did'nt have a DM)
I have done this (searching for dropped stuff) a few times before and decided to do it again. So I made the student how dropped the weight belt hold my smb and went down to search, unspooling the reel as I went along, I reached the end of the spool but could see that the bottom was relatively near. The depth turned out to be 34m+- at the bottom, I was constantly checking on my air (I had about 160bar) while searching, I spent about 12mins searching before I found the weights (10lbs in total)
I then used my BCD to surface while constantly monitoring my dive comp and releasing air when needed to prevent a fast ascent

On hindesight I guess I was real lucky nothing happened at that depth and that it will be a wiser/safer choice to have let it be.

If you repent and tell the class not to do what you did, and explain to them why it was not good judgment, you can be forgiven.

 

[dumpsterDiver]

It's kind of right on the limit - as per the PADI Search and Recovery...



A risk assessment, coupled with professional knowledge, should have identified the hazards involved with the recovery. As instructors, we get used to conducting risk assessments when dealing with students. Sometimes complacency sets in and we forget to do them for ourselves...

Sorry it has been a long time since I took a scuba course. I have brought up many weight belts by simply wearing them. I might draw the line at around 20 lbs, depending on my BC capacity. Of course if you are wearing the belt, the chance of it breaking free, should be no more than your other normal weightbelt, so the opportuntity for a runaway ascent from dropping a 10-lb belt you found should be LESS than that caused by the loss of the 20 lb belt you might be wearing. RIGHT?

 

[Abdullah]

Sorry it has been a long time since I took a scuba course. I have brought up many weight belts by simply wearing them. I might draw the line at around 20 lbs, depending on my BC capacity. Of course if you are wearing the belt, the chance of it breaking free, should be no more than your other normal weightbelt, so the opportuntity for a runaway ascent from dropping a 10-lb belt you found should be LESS than that caused by the loss of the 20 lb belt you might be wearing. RIGHT?

The SMB wasn't doing much good on the surface. A better use would have been to attach it to the weight belt to make it neutral. Then swim it up to the surface, controlling the SMB's ascent along the way. But that would have required some minimal pre-dive planning, and I think it's been established that there wasn't a plan.

 

[supergaijin]

Agree with DumpsterDiver- an extra 4-5 kg isn't a big deal for an experienced diver. Just buckle the belt, inflate the BCD and ascend. IMO there is no need to attach an SMB and could possibly break the SMB unless it had reinforced stitches.

34m is a deep solo dive and criticism is warranted that the diver descended to depth and then thought about the what if scenario.

To the OP Mike75- don't beat yourself up about it... lessons learned and all that. 'Good' instructors have all made mistakes. I reckon every human alive has made mistakes sometime in their lives which could have been fatal if the god's were unfavourable. Learn from it and move on.

 

[mike75]

thanks for all the comments guys,

 

[KD8NPB]

You can't put an extra 10 lb weight belt on and just ascend normally? Why mess with a liftbag for 2 5 lb weights?

What happens if you drop it?

Ascent rate violation = microbubbles = microbubbles combine to form big bubbles. Especially at that depth where you're ingassing nitrogen by the metric ton. It might be enough to throw you from the silent bubbles region to DCS, because at that depth with compressed air, you're sure as heck pushing into the safety margin, maybe past it if you have an undiagnosed PFO.

 

[dumpsterDiver]

What happens if you drop it?

Ascent rate violation = microbubbles = microbubbles combine to form big bubbles. Especially at that depth where you're ingassing nitrogen by the metric ton. It might be enough to throw you from the silent bubbles region to DCS, because at that depth with compressed air, you're sure as heck pushing into the safety margin, maybe past it if you have an undiagnosed PFO.

. Of course if you are wearing the belt, the chance of it breaking free, should be no more than your other normal weightbelt, so the opportuntity for a runaway ascent from dropping a 10-lb belt you found should be LESS than that caused by the loss of the 20 lb belt you might be wearing. RIGHT