double bladder

[Scubaroo]

Generally the consensus is that while diving wet in an area with a deep or nonexistent floor (i.e. ocean or large cave) a redundant BC is a good idea. Many people feel that a diver diving a dry suit could use the suit for emergency buoyancy. This assertion is quite reasonable but should be practiced to determine one's proficiency.

Turns out the reference is not in the DIR-F book (I was going from memory, my copy is out on loan), but the above quote is taken from the GUE website.

The quote is actually from http://www.gue.com/equipment/jj-hogarth.shtml

I guess if you want to be accurate it's Hogarthian, but not DIR, if read in the context of the article.

 

[Doc Intrepid]

Turns out the reference is not in the DIR-F book (I was going from memory, my copy is out on loan), but the above quote is taken from the GUE website.

The quote is actually from http://www.gue.com/equipment/jj-hogarth.shtml

I guess if you want to be accurate it's Hogarthian, but not DIR, if read in the context of the article.

Knew I'd heard Jarrod support the use of dual bladders under proscribed circumstances, but couldn't find the quote. Thanks for the citation.

 

[Mako Mark]

I remember when the DSAT tec deep course came out and Karl Shreeves caused a ruckus by insisting on redundant buoyancy, all sorts of fights erupted. I personally find in most situations I feel it is not scary, although I also don't prescribe that the danger of it suddenly causing a buoyant situation outweighs the benefit of redundancy. I just find them too bulky, and I generally dive in shallow caves. worst case scenario, I can walk out. Deep with multiple stages, I would seriously consider it, but OTOH, in that situation I would probably be diving dry anyway.

JM2C

 

[MikeFerrara]

If some one walked out of a system like Peacock the vis would be blown for a week but that wouldn't be the worst of it...In some places the line is way off the bottom and the silt could be several feet deep. That means you'd be walking through black soup and making your way out without a line. LOL

If one was diving in a wets suit and lost their bc, I can see a problem even with a balanced rig (one you can swim up)...and that is that swimming up in a cave doesn't get you any place. You need to swim horizontally and you want to do it without making a mess in that deep black silt I mentioned above.

And...even if you can swim a rig up what if you have a bunch of decompression.

Personally my answer is that I hate wet suits and dive a dry suit almost everywhere. If I were to be diving caves or dives that required staged decompresison in a wet suit I'd have to give some thought to a second wing...or going back to the dry suit.

 

[jonnythan]

Hey Mike, let me ask you something just out of curiosity.

It seems to me that using a drysuit to offset, say, 20 pounds of gas when you totally blow a wing would be a royal pain in the butt compared to using a redundant bladder that's not hooked up until you need it.

The "it's different from your normal procedure" argument doesn't apply, because using a drysuit as buoyancy control isn't your normal procedure either.

So why not take the redundant bladder? It's not a failure point or anything.

 

[Derek S]

So why not take the redundant bladder? It's not a failure point or anything.

Because it's not DIR, and this is a DIR forum, Mr. Moderator.

 

[MikeFerrara]

Hey Mike, let me ask you something just out of curiosity.

It seems to me that using a drysuit to offset, say, 20 pounds of gas when you totally blow a wing would be a royal pain in the butt compared to using a redundant bladder that's not hooked up until you need it.

The "it's different from your normal procedure" argument doesn't apply, because using a drysuit as buoyancy control isn't your normal procedure either.

So why not take the redundant bladder? It's not a failure point or anything.

Speaking for myself and I think it's at least part way inline with whats DIR, the benefit of the dry suit with heavy tanks is the buoyancy from the air space created by the underguarments. In other words you shouldn't be too negative in the first place. Of course when you start talking double 104's and decompression/stage bottles you could have 20 pounds of gas or more so at the beginning of a dive. If you still have all your gas you haven't gone very far and probably don't have much deco or anything and if it's larter in the dive you may be very neutral. Either way if I don't see that it's a big deal if I have to shoot a little air in my suit for the swim out. If I'm cold and squeezed at deco, I might shoot some air into the suit anyway.

I just don't really feel the need for the second wing with a dry suit (and the right weight underwear). With a wet suit I'd probably give it some thought depending on the dive but like I said I don't use a wet suit much except for short shallow (warm) stuff and at 30 ft who cares anyway. LOL

BTW, I've only seen one wing fail such that it essentially wouldn't hold any air and that was a wing with a pull dump on the inflator that came apart. I don't use wings with pull dumps either any more.

 

[Doc Intrepid]

Because it's not DIR, and this is a DIR forum, Mr. Moderator.

Whether it is or isn't appears at least to be questionable, Derek. If you go to the GUE website and review what Jarrod wrote (post #61), Jarrod seems to be suggesting that under certain circumstances dual bladders might make sense.

"Generally the consensus is that while diving wet in an area with a deep or nonexistent floor (i.e. ocean or large cave) a redundant BC is a good idea".

Unless you're suggesting that Jarrod is a huge stroke who's never done a real dive in his life, you'll have to pardon me if I accept Jarrod's conclusion on the subject as a more appropriate pronouncement of 'whats DIR' than yours above.

 

[Derek S]

Whether it is or isn't appears at least to be questionable, Derek. If you go to the GUE website and review what Jarrod wrote (post #61), Jarrod seems to be suggesting that under certain circumstances dual bladders might make sense.

Unless you're suggesting that Jarrod is a huge stroke who's never done a real dive in his life, you'll have to pardon me if I accept Jarrod's conclusion on the subject as a more appropriate pronouncement of 'whats DIR' than yours above.

Doc,

I was just giving Jon a hard time, I know him personally.

I never officially congratulated him on his 'promotion', so that is my way of doing so. :14:

 

[Doc Intrepid]

Doc,

I was just giving Jon a hard time, I know him personally.

I never officially congratulated him on his 'promotion', so that is my way of doing so. :14:

By all means, please proceed to do so! Jon is an excellent moderator, however, he can always use some extra Special High Intensity Training to become even better. In fact, I heartily endorse your giving Jon all the Special High Intensity Training he can possibly handle! (I've been known to give him some myself from time to time! )

<but always with a grin!>