Incident Involving Drop Bottle and Deep Diving

I am obviously biased, but the way my group dive is that cylinders are marked a certain way, and there must be an analysis tape on the neck of the cylinder for that day with a signature and decimal point on it. If there isn't an analysis sticker, I will question why. If it has a signature, and the analysis sticker is complete, I trust that the person has analysed it and the contents are what they are supposed to be.

Regards
 
GLOC said:
I am obviously biased, but the way my group dive is that cylinders are marked a certain way, and there must be an analysis tape on the neck of the cylinder for that day with a signature and decimal point on it. If there isn't an analysis sticker, I will question why. If it has a signature, and the analysis sticker is complete, I trust that the person has analysed it and the contents are what they are supposed to be.

Regards
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I don't do trust me dives ,
 
Mr fish said:
I don't do trust me dives ,
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I get that Steve, and I think the point Andris is making is at what point do you trust the person whose job it is to analyse the cylinders to have done their job properly? Or does everyone in the 10 man team have to analyse all the gas?

The diving I have done hasn't involved a drop bottle, but has involved safety bottles which would be staged on the line. Those dives were with people I trusted. If it was a dive with unknowns, then it is a different game, but I wouldn't likely do a dive needing safety bottles with unknowns...

The main point I was trying to make above is that even someone else's twinset or stages must have an analysis sticker on it for me to make that dive with them. If not, I will ask the questions and wait until the gas is analysed and stickered up.

Regards
 
GLOC said:
I get that Steve, and I think the point Andris is making is at what point do you trust the person whose job it is to analyse the cylinders to have done their job properly? Or does everyone in the 10 man team have to analyse all the gas?

The diving I have done hasn't involved a drop bottle, but has involved safety bottles which would be staged on the line. Those dives were with people I trusted. If it was a dive with unknowns, then it is a different game, but I wouldn't likely do a dive needing safety bottles with unknowns...

The main point I was trying to make above is that even someone else's twinset or stages must have an analysis sticker on it for me to make that dive with them. If not, I will ask the questions and wait until the gas is analysed and stickered up.

Regards
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Just pulling your pisser m8. With you on what your saying , I always try to only use cylinders Iv tested my self , understand maybe that,s not always a simple thing to do ,
And yes I to trust a few lads I dive with , but only if I have no other choice ,
 
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GLOC said:
I get that Steve, and I think the point Andris is making is at what point do you trust the person whose job it is to analyse the cylinders to have done their job properly? Or does everyone in the 10 man team have to analyse all the gas?

The diving I have done hasn't involved a drop bottle, but has involved safety bottles which would be staged on the line. Those dives were with people I trusted. If it was a dive with unknowns, then it is a different game, but I wouldn't likely do a dive needing safety bottles with unknowns...

The main point I was trying to make above is that even someone else's twinset or stages must have an analysis sticker on it for me to make that dive with them. If not, I will ask the questions and wait until the gas is analysed and stickered up.

Regards
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I totaly understand the teem problem

I just make sure its me in the teem that does the analising.

And thats not even slightly intended as a joke

ATB

Mark
 
I like to analyse drop bottles on trips and always ask two other people to witness and agree bottles are labeled correctly. This works for my OCD and you do not rely on one person.

Regards
Tony
 
Tonyf said:
I like to analyse drop bottles on trips and always ask two other people to witness and agree bottles are labeled correctly. This works for my OCD and you do not rely on one person.

Regards
Tony
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And, I guess, that goes a long way to address a statutory Duty of Care in Law and therefore potential liability...

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Mark Chase said:
Only with Ali 80s

No problem with 250bar nitrox fills in steel 10s They were neg enough to slide as long as there was some angle in the line

If a strong current is to be expected then clip some lead to the tank neck ring


Our drop tanks are on a sofnalime barrel and have 6mm rope at MOD depth + 1m for the 9m tanks and +4m god forbid we used a 21m tank as we found depth length just didnt work. Deeper the tank more extra rope you need

At the bottom of the line is a clip that clips on to the tank neck ring & into a large loop in the roap

If you put an extra 4kg lead on the tank to sink it in a current you can unclip the lead and clip it to the deco tank line and clip the tank to your self so you dont have to manage the extra 4KG

Or if its all a bit stressfull, just ditch it its only lead.


I would have grave concerns about deflating a divers SMB in a stress situation.

Adding to that sending him down a negative tank of gas?

Doesent sound good to me

And my SMBs are crack bottle & C02 so a sod to reinflate if you delfate it for me

ATB

Mark
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Hey Mark,

Yeah our system (like everything) ain't perfect and its still evolving. I guess it originated with some of our guys diving with British deep wreck teams in Falmouth etc or British teams coming over to Ireland roughly 10 or so years ago to dive the north channel or Lusitania and we used elements of their systems etc. in what we currently have. Both in terms of our deco station system and the emergency response we tailored for our local conditions, the boats we use and the availability of gear to form dropsets etc.

The reason we deflate the bag which the lads didn't mention is we don't want to get the set hung up or entangled on the dsmb line under any circumstance. We tend to drop deep, very deep indeed and we've found the deeper you drop the more likely entanglement in the dsmb line is to occur. Our dives could typically be 115m, 130m or even 160m so a drop to 90m would not be out of the question.

The other thing is that once the deep set goes in (attached to the deflated dsmb) each subsequent set (mid-range and shallow) goes in along the deep drop line i.e. the deep drop set only has deep cyls on it - the rest of the line is clear. The *hope* is that with the dsmb line attached to the bottom of the deep drop the diver will be able to establish contact with the sets. There's no descending, reeling stuff up etc etc.

The system has been practicised but its very hard to get a group to blow off a load of gas and possibly a days charter going out to 100m to try a "full blown" scenario. That's a vulnerability all right.

How much faith do we have in the system? Well....some of use are team divers, other prefer the "starburst" formation. Some totally rely on the dropset, some treat the drops as a bonus and buddy or triple up and try and carry enough gas to get a diver out - scooters and third carbon cyls for each diver, some scooter solo with barely enough to get to even the deepest drop realistically. I'm not dwelling on the pros or cons of any of these.

All I know is that on any of these dives I tend to feel a wee bit of relief when I get shallower than 80m and quite relieved when passing 60m and once I retrieve my tally/tag and head up the lazy line towards the station passing 40m and back into the company of the rest of the team for the long shallow stops I know I'm almost home ;-)

Stress situation - yeah I've done enough topside support for Irish and British teams, yellow bag gas deployments etc to see a few mistakes all right and weaknesses in any response situation exposed so not totally deluding myself as to the invincibility of this or indeed any system

Hope that clarifies

Stephen
 
smcmullan said:
The reason we deflate the bag which the lads didn't mention is we don't want to get the set hung up or entangled on the dsmb line under any circumstance. We tend to drop deep, very deep indeed and we've found the deeper you drop the more likely entanglement in the dsmb line is to occur. Our dives could typically be 115m, 130m or even 160m so a drop to 90m would not be out of the question.
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So you deflate the DSMB on the surface and clip the deflated bag to the drop rope? I'm trying to figure out how you get the diver at say 60m to the hanging cylinders. Are they able to see them or?

Around here, the buoy and the cylinders won't hang in a straight line up and down (too much current going different ways) so we'd be limited to perhaps a lowest gas at say 30m. But there's little or no ambient light down there at 30m so unless we weight them very heavily and drop them really close to the diver in need they won't get to them.
 
Generally speaking we're talking about Western Approaches to the North Channel of Ireland is where we do our deepest stuff and the visibility would be quite good and the tides/currents would be moderate. There would be exceptions in the case of plankton blooms or red tides/algae which could occlude all light from the surface some months or even seasons. Ditto moving further east towards and past Malin Head where the tides get trickier. I myself have never had to use the system in anger but as I'm attached to the drop line by the dsmb I have the option of reeling it in or even just arm over arming my way to the line if its out of sight I guess.

It all depends on the context I guess. If you were coming screaming (up to 60m) from 95m solo and needing the sets in a bit of a hurry then I'd imagine things would get quite exciting. If the incident happened at 60m with other divers about and you're only starting to tap into your bailouts with the option of going onto 02 rebreather at 6m then you may not even need the deep and intermediate sets to get home and you may choose to delay sending up the yellow (if it all).
 
Ok thanks, we are considering your system for our next deeper dives. In conjunction with our normal safety diver to help "connect" the drop bottles with the ascending divers.
 
Yeah we do use surface support and support divers where we can. Sometimes they are hard to get. We tend to also only deploy a support diver when absolutely necessary - prefer to have the extra hands on deck to help the skipper if anything arises. Some of our reluctance is due to the risk to the support diver themselves (who watches the watchmen?) and also needing them to do shallow cover on the deco station at the end where the last two remaining divers are finishing up. We don't leave anyone alone in the water on deco at the end of a long run. Support diver is last out.
 
And make sure you have walked your skipper through how your drop set system operates especially if there's more than one i.e an intermediate and shallow dropset as well.
 
I'm not a lawyer, qualified or 'barrack room' but I suggest if you wish to find out more, get charged with negligence see how quickly the prosecution refer to a duty of care...

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cathal said:
Thanks for that explanation of duty of care so under what law does this duty of care exist ?
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In the case mentioned by the OP, the charter boat, skipper or divemaster could be considered to have not exercised a reasonable care in dropping unmarked and unanalyzed bottles to the divers. Sure those divers should have been responsible for their analysis and marking. But that doesn't make the complicity of the boat/skipper/divemaster in using them more reasonable. In other words, its pretty hard to defend yourself from an angry widow when your practices are that far outside the boundaries of what prudent normal divers/skippers/DMs do.
 
Richard,

Interesting point. As with many aspects when looking at safety and incidents, it depends. Depending on where you are in the world, "prudent" has very different connotations and, because there are no formal rules governing these activities, I would expect those defending what happened to turn to the social norms of the location where the activity took place. If you go to dive in South East Asia with a 'sausage machine' dive centre, I wouldn't necessarily expect that they would have the same outlook on life (and subsequent) practices as somewhere in the US or the UK. To me this means that the burden of responsibility to make sure that the mitigations you want (and expect) are indeed in place and not to rely on someone else to do it.

Duty of care is a local definition, and therefore if you are in certain places in the world (the Middle East springs to mind), and someone owes you a duty of care but subsequently fails to deliver and you get injured or killed, because you are a foreigner, you will be in the wrong even if it is obviously not the case...

Regards
 
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