Did my AOW class this weekend and while we were doing my search and recovery dive, i went to fill the lift bag with my ATX40 octo and it began to freeflow. I tried everything to stop it, but all without luck. I turned down the airflow stuck my finger in it and nothing would work. It was spitting out ice chunks it was so bad. (The water was in the 40's) What could i have done to stop the freeflow without turning off the gas? With all my great instruction i was smart enough to get ready to ditch the weights but managed to surface(only about 5-10' deep at the time) and fill my bc. I bought Apeks under the impression freeflows were next to none. What happened and what could i do in the future to prevent it?
AOW and freeflow
- Thread starter scottyroz
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scottyroz:
I believe the ATX50 is where the line is drawn for performance and freeflow capabilities in the second stages.
I have an ATX200 w/ an AIR2 as my octo and I've not had a problem. I just picked up an ATX50 which I plan of hooking up to my SPM25AF on my doubles. I had a wicked freeflow w/ my SP reg at 120' with water in the 30's last year and havn't given them a chance to redeem themselves. I took them to the shop to have them detuned and will try them out at Gilboa with my doubles.
One thing I'd suggest differently is to add air to the lift bag in moderation. Pushing the plunger and firing for full effect pushes alot of gas through the regulator. The action of the gas expanding will make the reg get cold, hense the ice. Ice in any mechanical parts leads them to freeze open - hense the freeflow. However if you add air to the bag is small doses - ala your breathing pattern - you should be in a better situation.
-netmage
scottyroz:
First, I hope you were kidding about dropping weights at depth because of a free flow.
Second, I would be very careful about filling lift bags with my own breathing supply in cold water.
A couple of alternative techniques --
You could try filling the lift bag from the reg in your mouth by hold the opening of the bag where it will catch the exhaust bubbles, then taking a couple of deep breaths. This was taught to me by my first tech instructor, though I've got some reservations about having anything dangly up close to my head / reg / manifold underwater.
I've started using the Halcyon SMB's instead of a traditional lift bag. Instead of inflating them from a reg you unplug your drysuit, push the low pressure hose up against the fitting on the SMB, and off it goes. The low pressure hose is not capable of locking to the SMB the way it does to a drysuit or BCD (unless it gets damaged first).
I can add that we routinely inflate traditional lift bags from Apeks ATX50's and 200's without difficulty in our mid 40's water here.
Best Regards,
Merlin
You could try filling the lift bag from the reg in your mouth by hold the opening of the bag where it will catch the exhaust bubbles, then taking a couple of deep breaths. This was taught to me by my first tech instructor, though I've got some reservations about having anything dangly up close to my head / reg / manifold underwater.
I've started using the Halcyon SMB's instead of a traditional lift bag. Instead of inflating them from a reg you unplug your drysuit, push the low pressure hose up against the fitting on the SMB, and off it goes. The low pressure hose is not capable of locking to the SMB the way it does to a drysuit or BCD (unless it gets damaged first).
I can add that we routinely inflate traditional lift bags from Apeks ATX50's and 200's without difficulty in our mid 40's water here.
Best Regards,
Merlin
scottyroz:Yeah my instructor said to fill it in spurts next time. He said hes gonna have me practice with 50lbs of muscles in the lift bag the next time
You shouldn't be filling the lift bag with a second stage in the first place. Short spurts or not. There are other safer and more efficient ways to do this that your instructor ***should*** know.
You might consider talking to someone more familiar with proper lift bag use.
I wasnt kidding i was out of air completely. I got to the surface (since i was unable to stop the freeflow at depth) and add air to my bc so that i would float at surface. I didnt need to drop weights since there was enough air to keep me floating otherwise i would have had a problem. Is this not the correct thing to do?MikeFerrara:
Well I learned that the hard way which is sometimes a good thing. What other ways could i have inflated if not with my own breathing supply?MikeFerrara:
MechDiver:
I'll bite -- I'm an instructor and I can only think of the following:
1. Inflate from your octo.
2. Inflate from your primary like I was taught, but don't like.
(long hose/necklace changes the above around, but the meanings are the same)
3. Use a sealed bag and inflate a from a low pressure hose, either your drysuit, BCD (eek!), or an extra hose (eek!).
4. Like #3, but from an extra scuba cylinder you carry just for this purpose (appropriate for very large bags).
5. Inflate from a CO2 cannister that's built into the lift bag.
What am I missing or did you mean one of the above?
I'm taking your advice and talking to someone more familiar with lift bag use
My personal choice is to use a sealed bag with a LP connector, but if there is a better way to use an open ended bag I'd love to hear it.
scottyroz:
Ditching weights at the surface is of course ok. At depth it's an absolute last resort. Prior to deciding to do a buoyant ascent you would share with a buddy or failing that you would attempt an ESA with all equipment, including weights, in place.
If I'm going to be filling lift bags (for lifting) I'd rather carry a seperate supply to fill off of.
Under the right conditions I might fill from my breathing supply but...
Atticus:I'll bite -- I'm an instructor and I can only think of the following:
1. Inflate from your octo.
2. Inflate from your primary like I was taught, but don't like.
(long hose/necklace changes the above around, but the meanings are the same)
3. Use a sealed bag and inflate a from a low pressure hose, either your drysuit, BCD (eek!), or an extra hose (eek!).
4. Like #3, but from an extra scuba cylinder you carry just for this purpose (appropriate for very large bags).
5. Inflate from a CO2 cannister that's built into the lift bag.
What am I missing or did you mean one of the above?
I'm taking your advice and talking to someone more familiar with lift bag use
My personal choice is to use a sealed bag with a LP connector, but if there is a better way to use an open ended bag I'd love to hear it.
Inflation would depend somewhat on what the bag was used for, as well as the style of bag.
Closed bags are easy and obvious, so open bags. I will fill an open DSMB with exhaust bubbles, but I use a closed bag most of the time for that, as well as lifting if needed.
If I was taking an open bag(s) to use for S&R, I would have an extra LP hose with a nozzle attached and would use that only. You **could** prime the bag with exhaust bubbles but it would not be the safest method by any means. Depending on how big the job is would determine whether I took a pony for the inflator or just used backgas. Either way, the chance of the inflator freeflowing is just about nil.
Having been through a number of AOW S&R classes in warm water where the primary or octo was used, I cannot blame the poster for following his instructors lead. But, for coldwater, as Mike indicated, using your primary air source in a condition that is prone to create freeflows, the instructor should have known better IMO.
MD
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