back up Bouyancy ( SMB&DualBladder)

chucklindsey · March 25th, 2008, 08:06 PM

All,
Well im sitting here scratching my head. Recently read an IANTD course curriculum that stated the use of an SMB for redundant bouyancy source. Can anyone GUE certified touch on this, pros cons etc?

Also, pros/cons on a dual bladder system. Thanks in advance!

Chuck
Deep-Descent

***Fiona*** · March 25th, 2008, 08:27 PM

I am surprised you joined this forum.

Quote: (Originally Posted by chucklindsey)

On another note guys, i really dont give a S#$@ about DIR, I have 1000s of dives some very serious and have no room for the propaganda. i do agree with 90 percent of it and practice many of the same ideals however it is not gospel to me.

Quote: (Originally Posted by chucklindsey)

I forgot I put a DIR forum on the site, it was really just to apease my over zelous self ritious some what narrow minded dive buddy!

John I love you man! And originally it was to torment him with DIR bashing, most of which i do only because it upsets him more then anything. I mean i could say something about his mother and it wouldnt bother him but say something negative about JJ or the mighty "H" and Oh man its fighting time!

TobyFish · March 25th, 2008, 08:38 PM

discussion here

Alternate lift device

*Fredrik Taule* · March 25th, 2008, 09:32 PM

Quote: (Originally Posted by chucklindsey)

All,
Well im sitting here scratching my head. Recently read an IANTD course curriculum that stated the use of an SMB for redundant bouyancy source. Can anyone GUE certified touch on this, pros cons etc?

Also, pros/cons on a dual bladder system. Thanks in advance!

Chuck
Deep-Descent

Assuming the diver is properly weighted and dives a balanced rig, under what kind of circumstances are you seeing a need for redundant bouyancy?

Though the drysuit is not regarded as a bouyancy control device per se, it can undeniably provide additional lift in order to help the diver remain neutrally bouyant in case there is a leak from the wing (as demonstrated by the vast number of 'too much lead carrying' recreational divers who are using the drysuit as their only bouyancy control device).
Keep in mind that provided the diver is properly weighted, with a membrane suit he's only compensating for the weight of gas in his cylinder(s).
The discussion on drysuit being a 'back up' source of bouyancy or not is a pretty long and nuanced discussion, and I hope that I'm not causing any confusion by cutting it short.

I want to say that it's completely unlikely that all gas will be lost from a failing wing, but I'm sure someone will arrest me on that if I put it that way

So, it's highly unlikely that all gass will escape from a failing wing. We sometimes 'steal' eachothers wing OPV if things get too boring. Most divers don't notice any shift in bouyancy or realize that it's gone before they need to vent gas from the wing. Depending on where the leak is, shifting ones trim will help save gas in a leaking wing.

Speaking from my own experience I've managed to pull off my inflator going up a fissure crack at nintyish meter with +/- 2 hour decompression and a kilometer exit from the cave left to do. I can't say that really changed anything except for not finding the inflator when trying to reach for it the first 15 mins after it was gone. Considering the above, if I someone can steal my OPV at the bottom of my wing or loosing the inflator from the upper part of the wing without impacting the rest of my dive in any signifficant way, that provides the comfort I need with regards to having satisfactorily means to controll my bouyancy.

If loss of bouyancy due to suit compression in a neopren wetsuit is signifficant enough to cause problems, I'm guessing that more often than not a membrane suit with appropriate undergarment will be a preferred solution.

Weighing that against dual bladders, inflators, hoses, failure modes and procedures for managing the extra kit I find it difficult to see how dual bladder systems can be benefitial.

Hope that makes some sense to you!

Best,
Fredrik

rjack · March 25th, 2008, 11:14 PM

Quote: (Originally Posted by Fredrik Taule)

I want to say that it's completely unlikely that all gas will be lost from a failing wing, but I'm sure someone will arrest me on that if I put it that way

But that's what the bungies are for!!

Quote: (Originally Posted by Fredrik Taule)

We sometimes 'steal' eachothers wing OPV if things get too boring. Most divers don't notice any shift in bouyancy or realize that it's gone before they need to vent gas from the wing.

Now that's way better than piling rocks on their doubles

chucklindsey · March 26th, 2008, 02:31 AM

Fiona, I see you found our fun loving forum

we like to joke and poke at my over zelous dive buddy. John your the best man!

Seriously though Im coming around to most things. I will say i have learned more on this site then any other you guys rock! Fredrik, thanks for the info bro!

Best wishes all from PR!

Chuck
Deep-Descent

Ali Fikree · March 26th, 2008, 06:29 AM

HI Chuck & welcome

If you have a properly balanced rig you dont need redundant buoyancy. As you know, the key component to proper buoyancy is diving a well balanced rig. In the event of a wing failure, you should be able to swim your rig and hold the stops.

Redundant wings have an array of issues-some that I have personally seen and encountered. These issues are and not limited to another task to manage or task loading, more drag, and another inflator that could stick or leak etc...

I looked at your website and the amount of dives you have done, so you should understand what a well balanced rig is.

Best & dive safe,

A

**keri.lewis** · March 26th, 2008, 10:09 AM

Adding to Fredrik and Ali's posts -

I guess it comes down to how many failures you want to plan for..

I have tested the balance of a full rig by swimming up. I did a simulated ascent from 30M with stops of up to 5 mins at 6M.. not very long deco. I was able to do it - but it was tiring. It added CO2 to the mix in my body - and I am sure that it wouldn't be the cleanest deco imaginable.

Years ago I was taught the back-up process of using an SMB or lift bag as an alternate flotation device. I have to say it would have made the deco stops easier.

If starting from deep - you ride the partially inflated SMB up - keeping the dump valve uppermost and a hand on the string to control the ascent. (Much like using the wing dump.)

When you reach proper deployment depth release the SMB and "Climb" the string. You will need the surface marker for the boat.

Agreed it's not a DIR approach - and there are alternative ways a team could make this easier. (Emergency flotation sitting on your buddies for a start.) You also wouldn't get much out of one of the tiny DSMBs - and I'm not sure how you would deflate it anyway..

As with all emergency drills, it's only useful if practised. So as I don't practice it - I don't plan on doing it any time soon.. but it's useful to know it's there. You never know when multiple, safety-critical failures happen..

The truth is there somewhere...

TobinGeorge · March 26th, 2008, 06:01 PM

Redundant bladder wings + a wetsuit, besides all of the operational drawbacks usually end up being a means of spending another $300-400 on the enevitable Drysuit.

The wetsuit diver that wants to dive steel doubles in ocean, but can't yet afford a drysuit decides to buy a redundant (double bladder wing), and ends up spending far more than they would for a nice conventional wing.

After a few dives, freezing their A$$ off in their wetsuit they are convinced they do need a drysuit, only problem is they are now $300-400 further away from buying one.

Classic newbie "tax"

Tobin

March 25th, 2008, 08:06 PM	#1 (permalink)
chucklindsey(Offline) New Member Join Date: Sep 2007 Location: Alaska/Puerto Rico Posts: 4	back up Bouyancy ( SMB&DualBladder) All, Well im sitting here scratching my head. Recently read an IANTD course curriculum that stated the use of an SMB for redundant bouyancy source. Can anyone GUE certified touch on this, pros cons etc? Also, pros/cons on a dual bladder system. Thanks in advance! Chuck Deep-Descent __________________ Chuck Lindsey www.deep-descent.com

March 25th, 2008, 08:27 PM	#2 (permalink)
*Fiona* (Online) Moderator Join Date: Sep 2006 Location: Up North Posts: 1,206	I am surprised you joined this forum. Quote: (Originally Posted by chucklindsey) On another note guys, i really dont give a S#$@ about DIR, I have 1000s of dives some very serious and have no room for the propaganda. i do agree with 90 percent of it and practice many of the same ideals however it is not gospel to me. Quote: (Originally Posted by chucklindsey) I forgot I put a DIR forum on the site, it was really just to apease my over zelous self ritious some what narrow minded dive buddy! John I love you man! And originally it was to torment him with DIR bashing, most of which i do only because it upsets him more then anything. I mean i could say something about his mother and it wouldnt bother him but say something negative about JJ or the mighty "H" and Oh man its fighting time! __________________ Fiona Resistance was Futile Move Along YD GUE Member

March 25th, 2008, 08:38 PM	#3 (permalink)
TobyFish(Offline) Fine Upstanding Member Join Date: May 2006 Location: Telford, UK Posts: 795	discussion here Alternate lift device __________________ Rude-boy Volvo "Gangsta Rollin' in me nine-six-oh"

March 25th, 2008, 09:32 PM	#4 (permalink)
Fredrik Taule(Offline) GUE Instructor Join Date: Oct 2006 Location: Oslo, Norway Posts: 45	Quote: (Originally Posted by chucklindsey) All, Well im sitting here scratching my head. Recently read an IANTD course curriculum that stated the use of an SMB for redundant bouyancy source. Can anyone GUE certified touch on this, pros cons etc? Also, pros/cons on a dual bladder system. Thanks in advance! Chuck Deep-Descent Assuming the diver is properly weighted and dives a balanced rig, under what kind of circumstances are you seeing a need for redundant bouyancy? Though the drysuit is not regarded as a bouyancy control device per se, it can undeniably provide additional lift in order to help the diver remain neutrally bouyant in case there is a leak from the wing (as demonstrated by the vast number of 'too much lead carrying' recreational divers who are using the drysuit as their only bouyancy control device). Keep in mind that provided the diver is properly weighted, with a membrane suit he's only compensating for the weight of gas in his cylinder(s). The discussion on drysuit being a 'back up' source of bouyancy or not is a pretty long and nuanced discussion, and I hope that I'm not causing any confusion by cutting it short. I want to say that it's completely unlikely that all gas will be lost from a failing wing, but I'm sure someone will arrest me on that if I put it that way So, it's highly unlikely that all gass will escape from a failing wing. We sometimes 'steal' eachothers wing OPV if things get too boring. Most divers don't notice any shift in bouyancy or realize that it's gone before they need to vent gas from the wing. Depending on where the leak is, shifting ones trim will help save gas in a leaking wing. Speaking from my own experience I've managed to pull off my inflator going up a fissure crack at nintyish meter with +/- 2 hour decompression and a kilometer exit from the cave left to do. I can't say that really changed anything except for not finding the inflator when trying to reach for it the first 15 mins after it was gone. Considering the above, if I someone can steal my OPV at the bottom of my wing or loosing the inflator from the upper part of the wing without impacting the rest of my dive in any signifficant way, that provides the comfort I need with regards to having satisfactorily means to controll my bouyancy. If loss of bouyancy due to suit compression in a neopren wetsuit is signifficant enough to cause problems, I'm guessing that more often than not a membrane suit with appropriate undergarment will be a preferred solution. Weighing that against dual bladders, inflators, hoses, failure modes and procedures for managing the extra kit I find it difficult to see how dual bladder systems can be benefitial. Hope that makes some sense to you! Best, Fredrik __________________ Oceanic Tech, Fue.no - www.fue.no Last edited by Fredrik Taule; March 25th, 2008 at 11:41 PM.

March 26th, 2008, 02:31 AM	#6 (permalink)
chucklindsey(Offline) New Member Join Date: Sep 2007 Location: Alaska/Puerto Rico Posts: 4	Fiona, I see you found our fun loving forum we like to joke and poke at my over zelous dive buddy. John your the best man! Seriously though Im coming around to most things. I will say i have learned more on this site then any other you guys rock! Fredrik, thanks for the info bro! Best wishes all from PR! Chuck Deep-Descent __________________ Chuck Lindsey www.deep-descent.com

March 25th, 2008, 11:14 PM	#5 (permalink)
rjack(Offline) wet behind the ears Join Date: Nov 2005 Location: Seattle, WA Posts: 861	Quote: (Originally Posted by Fredrik Taule) I want to say that it's completely unlikely that all gas will be lost from a failing wing, but I'm sure someone will arrest me on that if I put it that way But that's what the bungies are for!! Quote: (Originally Posted by Fredrik Taule) We sometimes 'steal' eachothers wing OPV if things get too boring. Most divers don't notice any shift in bouyancy or realize that it's gone before they need to vent gas from the wing. Now that's way better than piling rocks on their doubles

March 26th, 2008, 06:29 AM	#7 (permalink)
Ali Fikree (Online) New Member Join Date: Dec 2005 Location: Dubai Posts: 463	HI Chuck & welcome If you have a properly balanced rig you dont need redundant buoyancy. As you know, the key component to proper buoyancy is diving a well balanced rig. In the event of a wing failure, you should be able to swim your rig and hold the stops. Redundant wings have an array of issues-some that I have personally seen and encountered. These issues are and not limited to another task to manage or task loading, more drag, and another inflator that could stick or leak etc... I looked at your website and the amount of dives you have done, so you should understand what a well balanced rig is. Best & dive safe, A __________________ Four wheels move the body, two wheels move the soul Last edited by Ali Fikree; March 26th, 2008 at 06:33 AM.

March 26th, 2008, 10:09 AM	#8 (permalink)
keri.lewis(Offline) Back in the water.. Join Date: Nov 2007 Location: Hampshire Posts: 386	Adding to Fredrik and Ali's posts - I guess it comes down to how many failures you want to plan for.. I have tested the balance of a full rig by swimming up. I did a simulated ascent from 30M with stops of up to 5 mins at 6M.. not very long deco. I was able to do it - but it was tiring. It added CO2 to the mix in my body - and I am sure that it wouldn't be the cleanest deco imaginable. Years ago I was taught the back-up process of using an SMB or lift bag as an alternate flotation device. I have to say it would have made the deco stops easier. If starting from deep - you ride the partially inflated SMB up - keeping the dump valve uppermost and a hand on the string to control the ascent. (Much like using the wing dump.) When you reach proper deployment depth release the SMB and "Climb" the string. You will need the surface marker for the boat. Agreed it's not a DIR approach - and there are alternative ways a team could make this easier. (Emergency flotation sitting on your buddies for a start.) You also wouldn't get much out of one of the tiny DSMBs - and I'm not sure how you would deflate it anyway.. As with all emergency drills, it's only useful if practised. So as I don't practice it - I don't plan on doing it any time soon.. but it's useful to know it's there. You never know when multiple, safety-critical failures happen.. The truth is there somewhere... __________________ Even a "bad" day diving beats a day in the office... Keri The more I learn.. the more ignorant I realise I am..

March 26th, 2008, 06:01 PM	#9 (permalink)
TobinGeorge(Offline) New Member Join Date: Nov 2005 Location: Southern California Posts: 566	Redundant bladder wings + a wetsuit, besides all of the operational drawbacks usually end up being a means of spending another $300-400 on the enevitable Drysuit. The wetsuit diver that wants to dive steel doubles in ocean, but can't yet afford a drysuit decides to buy a redundant (double bladder wing), and ends up spending far more than they would for a nice conventional wing. After a few dives, freezing their A$$ off in their wetsuit they are convinced they do need a drysuit, only problem is they are now $300-400 further away from buying one. Classic newbie "tax" Tobin __________________ http://www.deepseasupply.com