Redundant Bouyancy

[darylm74]

I am in the midst of my tech diving classes. My instructor teaches IANTD and DSAT. I have been diving a BP/W for the last 85 dives or so and doubles for most of my last 40 dives. I read the DIR Fundamentals book and geared my configuration towads this mentality. One of the discussions with my instructor, as well as a mentor of mine, is that in the ocean, with a wetsuit, you need a dual bladder wing. Based on my configuration and original thoughts, I felt that a bag was my backup redundancy, however I have started rethinking various scenarios and I am no longer sure. If I get a hole in my BC (not likely, but hypothetical), and am still negative due to gas, sure, I can blow a bag and/or kick the rig up, dependant upon required deco. The bag gives me plenty of bouyancy for hanging with deco, but what about once I get to the surface? If I were blown off a wreck, the boat's protocol is to stay with the diver(s) on the wreck. If I get done with my deco, and come up, and am in heavy waves, then what is a bag really going to do for me? A closed circuit bag, as sold by Halcyon, would provide a decent object to hang onto, but my current open circuit would not. Obviously I would need to keep my head above water, and it wouldn't take a lot of energy to kick up a little to stay above while on the surface, but if I was out for an hour, this might become too tiring to do depending on the environment. This may be a bit far-fetched, but I like to think outside the box.

Is a redundant bladder wing that important in the wetsuit / doubles scenario, or am I thinking too much? I mainly cold water dive with a drysuit and double 95s, and I have had to use my drysuit as redundant bouyancy before at the surface before. It worked great. My reason for asking is, I will be in my drysuit to finish tech, but we are discussing going to FL to do Trimix, lending to the possibility of doing it in a wetsuit. Most likely I will put some thin undergarments on and dive my drysuit because I trust it to back me up. If I should choose a wetsuit, I believe I may need to rethink my configuration

Oh, and before someone says, look it up, it has been discussed before, I realize this, and did a search first. I found several threads say they would blow a bag and use that as redundant bouyancy or swim the rig up. The part that is missing is, once you get to the surface, how are you going to stay up? I hope my questions make sense. My brain has been going a million miles an hour since my Advanced EANx class.

Thanks

Daryl

 

[daniel f aleman]

There are many threads on this exact subject - and as usual, there are two definite views on the matter. Do a "search", and be prepared to read for hours...

 

[do it easy]

Once you get to the surface, you could fasten your weights (and tanks) to the bag and float in your wetsuit.

 

[darylm74]

There are many threads on this exact subject - and as usual, there are two definite views on the matter. Do a "search", and be prepared to read for hours...

As stated in the original post, I've already done a search. I just didn't seem to find an answer about what to do post-surface. All the posts seem to cover pre-surface bouyancy issues.

BTW, interesting pic in your profile. A rather intimidating (but very cool) view on your way back up the line.

 

[darylm74]

Once you get to the surface, you could fasten your weights (and tanks) to the bag and float in your wetsuit.

Thank you for the insight.

 

[H2Andy]

As stated in the original post, I've already done a search.

don't mind him, he's usually just about that helpful

as an emergency issue, i would rather have a spare wing installed than be fidgeting with a bag or something. you gotta figure stress is likely to be high, and you don't want to add to the chain of events that lead to an accident by complicating things

i would go with the redundant bladder because the important part to me is to get my head above water safely

after that ... it's all details

btw, lots of people dive drysuits in Florida ... like you said, it's just a matter of the right undergarment

 

[daniel f aleman]

Well, your question has several answers - the most accurate will depend on your dive profile. My rule is that when you are at the surface you are a swimmer, and not a diver. Start there...

And could you be anymore exact about the "details" there, Andy?

 

[H2Andy]

it's just not helpful to tell someone who's said he's done a search to do a search

and you usually suggest that anyway ... just my pet peeve

 

[daniel f aleman]

http://www.scubaboard.com/showthread.php?t=180595&highlight=double+bladder

http://www.scubaboard.com/showthread.php?t=169212&highlight=double+bladder

 

[darylm74]

Well, your question has several answers - the most accurate will depend on your dive profile. My rule is that when you are at the surface you are a swimmer, and not a diver. Start there...

I'm thinking worst case scenario. You are in a wetsuit, and double steels(AL80s would be best possible positive bouyancy characteristics). You dive down on a wreck and a wire punctures your BC going in the door for a short swim through/penetration. (As said, this is thinking outside the box). You abort, and for some reason get blown off the wreck. So a) you are still full of gas and a little heavy and b) you are in a scenario where you are away from your team member(s) (I have the team mentality and not a buddy that is going blindly follow you off the wreck, so you're on your own). You have to come up, do your deco/stops on the lift bag and now you're heavy and drifting in heavy waves. The dive boat most likely saw your bag (provided you popped your bag in a reasonable amount of time, as taught) and now you gotta stay afloat for awhile while the boat waits for the rest of the divers to do their deco and come onboard before they follow the current to come get you.

Other than taking the double bladder advice, I like "do it easy"'s advice, get out of the rig (which IANTD actually teaches), clip it to the ring at the bottom of my bag and float in the wetsuit. I will most likely still either do the double bladder or stick with my drysuit (TLS350). If these options were not available at the time, I want to know my options.

Thanks again,

Daryl