Don't turn this into a "nanny state" argument. I believe firmly that Darwinism should be allowed to run its course. I'm completely open to a discussion about dive gear and dive techniques, and you haven't offended me. That's not the issue.
Back on topic: the question was redundant buoyancy in warm weather for deco purposes. Pete said he uses a balanced rig, diving all aluminum tanks and no backplate (due to sidemount). I don't dive deco but am about to start. I dive dry very often. If it's too warm for a drysuit, I'd probably move to a lift bag. My tanks are heavy steels, but I guess depending on the situation I could move to rented alu tanks. I think I just need to practice using a lift bag for buoyancy. I'd probably get a giant lift bag and use it as a wing, but with a reel attached....so if I have to I can let it go and use it as an "anchor line" to climb up. I'd probably need heavier line on my reel, though. I'll have to look at tensile strength of rope and then whatever reduction in that my knots are providing.
Dan, how do YOU deal with the need for redundant buoyancy in the tropics?
Hi Victor,
First I would have to separate this into two discussions...the "redundant buoyancy issue for recreational, and then the one for tech.
For recreational, there is never a depth I will reach, or a water temp too low, for a semi-dry suit like my wife Sandra just got to keep me warm....He;*, I'm still in my 2.5 mil wetsuit now! With 90% of these dives using a 80 cu ft Al tank, there is really no buoyancy concern going on--for me, or really for anyone I know that dives like this....the tank is so easy to swim up that this is a non-issue.....We also own some extremely heavy HP100's...which Sandra and I got more for Dry suit diving.....If I use one of these with my 2.5 mil suit and my 19 pound lift wing....at 60 or 100 feet deep feet deep, I am practically fully inflated to be dead neutral. My backplate is 6 pounds, add the sta and big video cannister light --try around 9 pounds...and the heavy tank is like 8 pounds....Now, I can easily swim this to the surface, especially with my big Dive R Freedive fins, or with Excellerating Force Fins, or Extra Force Fins...it might be a little challenge with Jet fins on....but typically I would not use this combo.....If I need more air for a 110 foot deep wreck dive, the better plan is a low pressure 120--which I can jack to being a 170 if I really want to
It makes me only about 14 pounds negative--not so bad as the hp100....still not really the right tank for the small 19 pound wing..but for the 2 blue moons a year where I decide this is what I need, this will work....Sandra has the Halcyon 30 pound wing, so for her, this is fine. I think this is more about deciding what is a good tank to be using.
If we are talking tech....even though this is the tropics, we get thermoclines often at 120 to 200 feet deep...and it can go from 79 in summer at the surface, to 53 on the bottom at 280. So any wetsuit, including the semi dry, is not going to do the job well....particularly as most wet suits have compressed so much at 280 feet, that they are about as warm as lycra at that depth....So here I really do have a desire to wear my TLS 350 Drysuit....with double 80 aluminums and a 30 cu ft al bottle with 100% O2 for deco. Dive duration is limited to 25 minutes--which allows this volume of gas to support me and Bill Mee, or one of my other buddies, even if one of us has a failure.
If I have a wing failure, I can swim this rig up from the bottom easily, without using the drysuit as an elevator
I don't believe in using larger and heavier tanks than the double 80's in ocean....280 is deep enough for the dive sites I care about, and we see alot in 25 minutes of bottom time...There are too many tradeoffs you have to begin losing benefits with, if you decide to start going much deeper, or much longer.
Conceptually, I am AGAINST REDUNDANT BUOYANCY-- I think this implies the diver is using the WRONG TANK, or is for some reason, so HEAVY on the dive that they need an elevator to get from the bottom to the surface.
REdundancy for me--is replaced by not being insanely heavy on the bottom--and by having fins on that offer propulsion that can easily carry even a good sized anchor up from the bottom if freediving ( or wearing a tank, and without using the BC for this). So my Dive R Freedive fins are sort of my alternative to redundant Buoyancy--in that I know that I can always swim myself or my buddy, up to the surface--and will never need an external elevator to assist me. These don't work well if I was doing a serious penetration in a wreck--but....there are few of these worthwhile to do...there is no gold or diamond stash to be found--and the best marine life is outside or just inside in the big easy access chambers where the freedive fins are fine....
[video=youtube_share;xKUgKhvcELk]http://youtu.be/xKUgKhvcELk[/video]
This wreck has the kind of penetration easily done with my big Dive R freediving fins---the ceiling is high, and there is no way I will silt in this environment....I wish I could say that for some of the other divers that enter into the wreck with normal small fins
There is actually a lower "room" right under this chamber--and it is tight with a low overhead...so it would be a place to use the Extra Force Fins.....the thing to get me down into it--is that sometimes a dozen or more of the goliaths are hanging out down in there--but this lower room dive is a serious and REAL Penetration dive, and the danger issue goes up by several orders of magnitude....You go from a really fun and easy dive--with great video opportunities, to a dive with some serious planning required--and where you MUST have only optimal dive buddies--and 2 of them, as on a high challenge dive, the video guy ( no matter how much they try to be attentive), is not always watching the buddies--he is watching the video subject---and so the video guy is really a dependent buddy.
---------- Post added December 6th, 2013 at 12:27 PM ----------
Let me share a "redundant Buoyancy" fatality story....
Back in the 90's, there was a tech diving instruction accident...the thread ran for months, and was called Divers Supply Triple Death Tragedy.
While I could go into great detail on this, as my team did many dozens of dives over many miles of deep reef in a vain attempt to find John Claypool's body ( a close friend of my brother's--and if there is no body found, a family can lose everything when there is no insurance pay off, from no proof of death).....
So...after MANY horrific errors of judgement, which led to one of the students running completely out of gas at around 260 to 280 feet deep....with the instructor Andre Smith choosing NOT to share gas with his OOA student....Smith and the others found that their heavy steel doubles and heavy steel stages, had them so heavy on the bottom that they could not swim up--initially, could not get the body off the bottom, and subsequent to this, had a hard time getting themselves off of the bottom...
So, from the account of the lone survivor, Andre decides to send up a lift bag, and to use this to get sufficient lift to reach the surface...potentially to help with the body as well.
Andre shoots the bag, but it has so much lift and he is so heavy, that the bag gets away from him, and shoots to the surface--no longer connected to andre, as it has the reel with it.
Claypool and the lone survivor, made multiple launches for the surface, which were visible as a see-saw series of depth reads on the computer of the survivor, and finally they made it to 100 feet, after many tries...they were quite hypothermic, as they were wearing thick wetsuits, which were useless on the bottom depth....bottom was in the high 50's or low 60's ( don't recall exactly). Claypool waits a few minutes, realizes his friend Andre was not making it up, so Claypool goes back down, after him, never to be seen again.
Andre apparently stripped himself out of his doubles, and tried, but failed to free ascend.....and bloat from three weeks or so underwater brought him to the surface a month later....where a fishing boat spotted a school of sharks on the surface, investigated, and found the dead Andre, bloated and floating with no tanks on.
Moral to the story? So many mistakes were made in pairing heavy steels, thick wetsuits, bungee wings in very cold water( speculation that the bungees tightened in the cold, and would not allow full inflation for the big wings they were wearing), an instructor leading by swiming 15 feet in front of students, not visually aware that one of the students ( the one that went OOA), was bumping into the bottom constantly, and could not swim well with his heavy weighting and malfunctioning BC. ....and there is speculation that Andre may have been diving deep on air...another reason he ditched his tanks to remove evidence....this ties to the shop and boat purposely giving us the wrong inituial dive site locations, as well as trying to keep us out of the water the first few days after the accident....The Sheriffs Department intervened, and ASKED us to find Claypool . But another moral to be learned is that even a very strong diver, in an emergency situation, may very easily FAIL to be able to hang on to a high inflation lift device not securely strapped to them like a BC or parachute. Sure there were proceedural errors in his deployment, but the idea is that a wing failure has precipitated a catastrophic emergency--you are stuck to the bottom like a hard hat diver with no line to the surface.....This is a scenario for absolute panic--or at least less than ideal skills performance based on anxiety..the deep air multiplier would be the icing on the cake..... This incident was one of the factors that led George and Bill Me and I, to push so hard for the concept of a "balanced Rig" you could swim off the bottom, and for not using heavy steel doubles on ocean dives--and IF you must, to NOT use them with wetsuits on Tech dives where they would lose their buoyancy and thermal protection.
