Fatality at Jersey Island

[darushin]

If that were possible, the rebreather would not meet (according to experts) Clause 5.1 of BS EN 14143:2013 (or its prior wording in BS EN 14143:2003), which states:

“It shall not be possible to assemble or combine the components or parts in such a way that it can affect the safe operation and safe use of the apparatus, e.g. by incorrect connection of the hoses to the breathing circuit.”

With The DSV in standard configuration, it is not possible to assemble it wrong. With the BOV upgrade purchased, it is possible. If you buy it stock you can't assemble the hoses wrong.

Daru

 

[gianaameri]

With The DSV in standard configuration, it is not possible to assemble it wrong. With the BOV upgrade purchased, it is possible. If you buy it stock you can't assemble the hoses wrong.

Daru

Is that with the Hollis BOV upgrade, or a BOV from another manufacturer retrofitted to a HP2?

Which year you received the "standard" version of your HP2 (non-BOV, standard DSV)?

 

[darushin]

Is that with the Hollis BOV upgrade, or a BOV from another manufacturer retrofitted to a HP2?

Which year you received the "standard" version of your HP2 (non-BOV, standard DSV)?

I purchased my P2 before the BOV was even available and received it almost 9 months or so after the unit. My BOV is not Keyed and can be installed upside down(I have been told it can also be reversed to be used on a Explorer). However when done so it becomes very obvious. In the default BOV config, the LP hose for the regulator runs up the left side and plugs into the BOV there. Installing the BOV backwards would cause the LP hose route in front of your face do a u-turn back into the BOV (not to mention the regulator being upside down). I have been told now though, that the BOV is keyed.

Furthermore, if I were to reverse the flow of my unit, the pre-dive check list would catch it or a very simple watching of the PO2 during pre-breath would make this evident (besides the stupid hard WOB). When reversed, the inhale causes a O2 drop and a exhale cause a O2 increase. I was trained when manually flying the unit to inject O2 on exhale because the O2 should be lower and also it helps to avoid "O2 pockets" in the loop.

Daru

 

[HIGHwing]

I have a Hollis P2 in my CCR "collection" and quite a few dives on it. Through time the P2 has emerged to be my favorite because it's so simple to assemble and use. Truth be told, I basically use it for all my diving just to spite one of the loudmouths in this thread.

I hate to admit it, but I have once assembled the hoses to the head backwards. Looking at the unit, I immediately noticed the error right away. The chest straps were in the wrong place, the O2 and Dil hoses were not the correct length, and the loop had a weird twist near the DSV.

The Cave Diver in me decided to breathe the unit on the surface before correcting the problem. Perhaps it would feel different? My curiosity was rewarded as the WOB was dramatically different with the loop installed backwards. Once you get the CLs dialed-in the WOB on the P2 is pretty amazing even where compared to any CCR I've dove or own. This dramatic WOB difference with the hoses backwards would be immediately noticed by *any* reasonably experienced P2 diver long before any positive/negative/stereo.

I submit the victim's lack of experience regarding the feel of the unit was a principle factor in her decision to dive the unit improperly assembled. Ultimately, she "passed" the unit based on binary information, the unit breathes, the unit maintains set-point, I can manually adjust the SP as expected, the unit is reasonably air-tight (I understand this is debated at this juncture). She didn't take the additional cues available to her, i.e. chest strap leads on the wrong sides, LP hose lengths are all wrong, perhaps an unusal twist in the loop near the DSV, and strange breathing characteristics. It could be said, she wasn't scared enough of the unit to fail the assembly/pre-dive/pre-breathe checklists over "something doesn't feel right" because she likely had very little experience to gauge it from.

If you own a P2 and this worries you a spot of colored paint on the head, and the loop hose connectors will give you an additional cue as well. I submit the WOB has such a different feel there is no way you wouldn't notice, unless you had a tremendous lack of experience to draw upon. If there was a design modification submitted to Holllis from this accident, I would key the head/hose connections and add colors to the hose/head connections. That said, the correct assembly is documented with pictures in the manual, and the training obviously would have covered this eventuality as a potential assembly risk. If Hollis wanted to take the design modifications slighly further the velcro/gigantic fastec fittings could be colored/reversed for an additional cue as well.

Quote whatever standards, CE, design, interstellar space, or whatever the diver either missed, or worse, disregared the strange circumstances during assembly.

 

[gianaameri]

I have a Hollis P2 in my CCR "collection" and quite a few dives on it. Through time the P2 has emerged to be my favorite because it's so simple to assemble and use. Truth be told, I basically use it for all my diving just to spite one of the loudmouths in this thread.

I hate to admit it, but I have once assembled the hoses to the head backwards. Looking at the unit, I immediately noticed the error right away. The chest straps were in the wrong place, the O2 and Dil hoses were not the correct length, and the loop had a weird twist near the DSV.

The Cave Diver in me decided to breathe the unit on the surface before correcting the problem. Perhaps it would feel different? My curiosity was rewarded as the WOB was dramatically different with the loop installed backwards. Once you get the CLs dialed-in the WOB on the P2 is pretty amazing even where compared to any CCR I've dove or own. This dramatic WOB difference with the hoses backwards would be immediately noticed by *any* reasonably experienced P2 diver long before any positive/negative/stereo.

I submit the victim's lack of experience regarding the feel of the unit was a principle factor in her decision to dive the unit improperly assembled. Ultimately, she "passed" the unit based on binary information, the unit breaths, the unit maintains set-point, I can manually adjust the SP as expected, the unit is reasonably air-tight (I understand this is debated at this juncture). She didn't take the additioanl cues available to her, i.e. chest strap leads on the wrong sides, LP hose lengths are all wrong, perhaps an unusal twist in the loop near the DSV, and strange breathing characteristics. It could be said, she wasn't scared enough of the unit to fail the assembly/pre-dive/pre-breathe checklists over "something doesn't feel right" because she likely had very little experience to gauge it from.

If you own a P2 and this worries you a spot of colored paint on the head, and the loop hose connectors will give you an additional cue as well. I submit the WOB has such a different feel there is no way you wouldn't notice, unless you had a tremendous lack of experience to draw upon. If there was a design modification submitted to Holllis from this accident, I would key the head/hose connections and add colors to the hose/head connections. That said, the correct assembly is documented with pictures in the manual, and the training obviously would have covered this eventuality as a potential assembly risk. If Hollis wanted to take the design modifications slighly further the velcro/gigantic fastec fittings could be colored/reversed for an additional cue as well.

Quote whatever standards, CE, design, interstellar space, or whatever the diver either missed, or worse, disregared the strange circumstances during assembly.

She may have had a different version from you.

Also, apparently both one-way valves ended on the same side of the DSV, so WOB was nil since she was breathing from a single hose into and out of the same counterlung.

 

[gobfish1]

once she put the lungs on the wrong side , it looks to me she just went dot to dot , as that the only way it would all fit ,
dsv was the right way , just bad news for her that the inhale flipper valve sits in the hose ,

so ended up butting both valves togeather on the right side blocking that side of the loop off ,
and only being able to use the left lung that now has no flipper valve

much like diving a bin bag and a garden hose, and thinking you have a rebreather ,

 

[gianaameri]

once she put the lungs on the wrong side , it looks to me she just went dot to dot , as that the only way it would all fit ,
dsv was the right way , just bad news for her that the inhale flipper valve sits in the hose ,

so ended up butting both valves togeather on the right side blocking that side of the loop off ,
and only being able to use the left lung that now has no flipper valve

much like diving a bin bag and a garden hose, and thinking you have a rebreather ,

That is what I understand from the Coroner and HSL findings posted on the net elsewhere:

• The rebreather had been put together such that the gas would not circulate in the required loop and CO2 would not be removed from the inhaled gas.
• The inhale counter lung was positioned to the diver’s right hand side, instead of the left hand side.
• The exhale counter lung was positioned to the diver’s left hand side, instead of the right hand side.
• The one way inhale valve that should be positioned on the inhale side of the mouthpiece, to ensure the gas circulated the loop, was found butted against the one way exhale valve of the mouthpiece stopping any gas passing into the exhale counter lung on the diver’s right hand side.

 

[HIGHwing]

She may have had a different version from you.

I doubt it. The Prism 2 has been pretty stable in configuration since new. For reference, I have the latest revision with the DiveCan Petrels. I have not modified the rig at all other than removing it from the shipping container.

Also, apparently both one-way valves ended on the same side of the DSV, so WOB was nil since she was breathing from a single hose into and out of the same counterlung.

Perhaps I was confused from the earlier back and forth. But my curiosity is definetly piqued. I will put my P2 together at home tonight in this fashion and breathe it. I want to see what it feels like with the 3.5 liter (standard) lungs.

My suspiscion is that if you managed to perform the assembly in this manner the loop *could* fail the negative test, and would absolutely immediately fail the positive and stereo tests. Either way, if you followed the checklist, and your training provided even a glimmer as to *why* you're doing these tests this unit would have completely failed the Assembly Checklist, as printed, in every edition of the product manual that I've ever read or used. Of this there is absolutely no debate whatsoever in my mind. I'm going to find out in a couple hours, and I will post a synopsis of my findings.

BTW - It's highly unlikely she had the 2.5 liter lungs. I ordered my P2 with the 2.5 liter lungs from Hollis in August 2013. Hollis shipped it with the 3.5L lungs because no 2.5L were available. I then had to order (at my expense) the 2.5L lungs. I ordered the 2.5L lungs in May and Hollis only had one 2.5L lung. They shipped one 2.5L lung, and I'm still waiting for the other one. Long and short is the 2.5L lungs are hard to get.

 

[gianaameri]

Ok, perhaps I was confused from the earlier back and forth. I will put my P2 together at home tonight in this fashion and breathe it. I want to see what it feels like with the 3.5 liter (standard) lungs. It's highly unlikely she had the 2.5 liter lungs. I ordered a set of the 2.5 liter lungs from Hollis in May 2014 and they still haven't been able to produce them and ship them despite running the credit card immediately. Hollis are you reading?

If you can assemble it incorrectly in that fashion let us know.

It would be quite relevant to the discussion.

---------- Post added December 2nd, 2014 at 01:56 PM ----------

I have the latest revision with the DiveCan Petrels. I have not modified the rig at all other than removing it from the shipping container.

Then your unit is different from the deceased unit because the Coroner was told the rebreather loop had been re-designed by Hollis after the fatality (as posted elsewhere on the net). I was told there were only 8 faulty or non-compliant units made.

 

[HIGHwing]

If you can assemble it incorrectly in that fashion let us know.

It would be quite relevant to the discussion.

I agree. I have to tell you though, the assembly procedure you're requesting required me to actually visualize if it is even possible. I just don't see how the knurled ring on the DSV has enough tolerance to allow both mushroom valves to be seated. My guess is the loop will not pass a negative because the loop will not be air tight. More on that later.

For those of you who somewhat familiar with rebreathers and following along, I want to make an overarching statement about the proposed assembly. This assembly procedure I'm going to replicate to my knowledge has never happened before in the wild. For this maganitude of an assembly error requires more than a single missed test on a list, or an oversight, essentially the majority of the loop has to be built incorrectly. As you may have noticed, I couldn't even intially understand how it was done desipte the lengthy discussion. It is my position prior to trying it in the first person there is no way this rebreather could possibly have passed the tests included in the Assembly Checklist.