Switching D/S and Wing Inflator Posts

[Flightlead]

I hope this doesn't turn into the all too common DIR flame war but...

I would like to start a conversation about the pros and cons of switching which post ones dry suit and wing inflator hose is connected to, from the "standard" technical standard of right post for wing and left post for dry suit to putting the wing on the left post and the dry suit on the right post. NAUI is apparently changing their NTEC (NAUI Technical Equipment Configuration) to reflect this change soon.

The most significant argument for this change I heard (or understood at my level) is that in the event of a roll off (left post) you would be in better shape loosing your wing inflation than your dry suit inflation. The argument went thusly:

In order to have a roll off you are in an overhead environment, such as a cave, and have contact with the ceiling. The most likely way to have this contact is when entering a descending section of cave/wreck from either a horizontal or ascending section (eg when swimming over a hump or restriction then heading down hill) and bumping the ceiling as it slopes down towards you. In this case you are descending in a head down position. As you descend, as we all know, you get increasingly negative and accelerate downwards unless air is added to one of your two (usually both) buoyancy control mechanisms: dry suit and wing. If one was to loose the wing, buoyancy could be controlled by adding air to the dry suit. However if dry suit inflation capability is lost, one might become so pinched in the descent as to restrict or prevent movement and therefore be unable to inflate the wing or perform any other activity.

I'm sure there are other arguements both for and against this configuration. I'd be interested in hearing them. Let me preempt any posts that might mention it by saying that obviously team consensus should be followed and if everyone else on the team is wing-on-right-post that should be a primary consideration.

 

[do it easy]

Use an argon bottle and some blue gloves and then there is no issue, unless you manage to roll off the argon bottle :11:

I think this is one of those issues solved by technique- checking valves and maintaining buoyancy. I would hope the diver would notice when the drysuit squeeze becomes immobilizing.

Really, I sometimes wonder about all the configuration options. I don't think that any one of them is optimal at all times, so it boils down to what scares you the most and what happens most often. These would be the high severity/low frequency and low severity/high frequency events.

 

[PerroneFord]

I'd hope that someone notices a drysuit squeeze on a descent before the 40-50ft drop necessary to make reaching the inflator very difficult. Not to mention, unless you are dropping down a vertical shaft, you're going to make contact with the bottom before you drop 40ft.

 

[TSandM]

Having been (in a drill) in the situation of having my dry suit too squeezed to reach valves, I can understand some theoretical concern about this. But if you're properly trained to check your left post after any contact with the ceiling, how likely is it that you'd descend enough to get into any trouble?

I'd hate to have to retrain all the circuits in my brain to remember everything backwards . . .

 

[SparticleBrane]

Sounds like a solution in search of a problem.

 

[do it easy]

I think the argument for the status quo has to do with breathing from the right post. Ostensibly, that post is more likely to freeflow, so in that case, you would shut it down. If you have the DS on the left post, you still have DS inflation and the mobility and buoyancy that comes with it. If you have the DS on the right post, this would put you in the same situation you are trying to avoid by swapping hoses.

Which would you consider more likely- freeflowing the right post or not noticing the drysuit squeeze?

 

[do it easy]

Sounds like a solution in search of a problem.

Nah, it's a good question- in the least, it's an exercise in risk management. Heck, I've lost sleep over the possible failure points of my p-valve.

Of course, it could also be a conspiracy with the hose manufacturers since everyone would buy new hoses to get the lengths just right

 

[JeffG]

I think the argument for the status quo has to do with breathing from the right post. Ostensibly, that post is more likely to freeflow, so in that case, you would shut it down. If you have the DS on the left post, you still have DS inflation and the mobility and buoyancy that comes with it. If you have the DS on the right post, this would put you in the same situation you are trying to avoid by swapping hoses.

Which would you consider more likely- freeflowing the right post or not noticing the drysuit squeeze?

also, the bc inflator can be a backup reg if the left post rolled off.

kinda hard to breath off your drysuit.

 

[Steve R]

I hope this doesn't turn into the all too common DIR flame war but...

I would like to start a conversation about the pros and cons of switching which post ones dry suit and wing inflator hose is connected to, from the "standard" technical standard of right post for wing and left post for dry suit to putting the wing on the left post and the dry suit on the right post. NAUI is apparently changing their NTEC (NAUI Technical Equipment Configuration) to reflect this change soon.

The most significant argument for this change I heard (or understood at my level) is that in the event of a roll off (left post) you would be in better shape loosing your wing inflation than your dry suit inflation. The argument went thusly:

In order to have a roll off you are in an overhead environment, such as a cave, and have contact with the ceiling. The most likely way to have this contact is when entering a descending section of cave/wreck from either a horizontal or ascending section (eg when swimming over a hump or restriction then heading down hill) and bumping the ceiling as it slopes down towards you. In this case you are descending in a head down position. As you descend, as we all know, you get increasingly negative and accelerate downwards unless air is added to one of your two (usually both) buoyancy control mechanisms: dry suit and wing. If one was to loose the wing, buoyancy could be controlled by adding air to the dry suit. However if dry suit inflation capability is lost, one might become so pinched in the descent as to restrict or prevent movement and therefore be unable to inflate the wing or perform any other activity.

I'm sure there are other arguements both for and against this configuration. I'd be interested in hearing them. Let me preempt any posts that might mention it by saying that obviously team consensus should be followed and if everyone else on the team is wing-on-right-post that should be a primary consideration.

Unreal, yet oh-so-typical.

How to prevent roll-offs causing a problem?

Check when you bump.

Problem solved.

Anything else is Sparticle's comment................solutions looking for a non-existent problem.

If that really is NTEC thinking, W*T*F* happened to them all of a sudden?

 

[SparticleBrane]

If anything, at least they're going through all the "What if?" scenarios. Better than I can say for most people...