Buoyancy

[Graeme Fraser]

If I have a bladder, then I use both. If I dive without a bladder, then just my lungs. They broke my bladder in the Philippines and I just dove without it. No one complained about my buoyancy except for one guy. He was pissed that mine was better than his and he had the use of a bladder! Go figure.

Use all your tools. My lungs are as much of a tool in diving as is any bladder. I use the bladder for coarse adjustments and my lungs for fine adjustments. This largely goes out the window when I'm on my rebreather, but not completely. In that case, a super breath will trigger my ADV (Automatic Diluent Valve) and add air. Of course, I can always exhale through my nose to vent any excess in my breathing loop. However, I have to add/subtract from my BC all the time on a rebreather which I rarely have to do while on OC.

This is the way I dive. This is how I teach it. If anyone doesn't understand or like it, then they are free to dive in any manner they want. I get compliments on my students' trim and buoyancy all the time because it's so easy that they look good from the start. In any event, just be safe and in control however you do it.

Sorry, I really don't mean to be obtuse, but isn't using BCD for coarse adjustment and lungs for fine adjustment standard practice, unless I'm missing something?

 

[Jcp2]

It may be part of standard teaching but clearly not standard practice. Maybe best practice.

 

[The Chairman]

You said "I rarely have any air in my BC"

I haven't dove backmount with a bladder on my BC since June. You can easily adjust your breathing to accommodate a 10 pound swing. I use a bit more air when I'm light, so I start a bit heavy, where I have to keep my lungs fuller at the beginning and a little bit empty at the end. Two pounds works well and the adjustment is pretty automatic. I even do this a bit when I have a bladder, but it's a bit of an advanced technique. I shared how I get my students started down the path of easy buoyancy control. Sorry for any confusion.

It is just too much work to compensate for the buoyancy swing full to empty using only lungs.

Sorry, but I don't find this to be true. But hey, everyone's a bit different and that's OK. Have fun, stay in control and stay safe.

 

[axluba]

I haven't dove backmount with a bladder on my BC since June. You can easily adjust your breathing to accommodate a 10 pound swing. I use a bit more air when I'm light, so I start a bit heavy, where I have to keep my lungs fuller at the beginning and a little bit empty at the end. Two pounds works well and the adjustment is pretty automatic. I even do this a bit when I have a bladder, but it's a bit of an advanced technique. I shared how I get my students started down the path of easy buoyancy control. Sorry for any confusion.

Holy Molly. And I am there no sure if a 14L (31#) wing would be enough for my first single tank rig...

Interesting read!

 

[The Chairman]

Interesting read!

Actually, this is how I first learned to dive back in 1969. They had horse collars back then, but I was a kid and couldn't afford that. When I got back into the sport, I really liked bladders because they kept you afloat AFTER the dive. So, now I carry a safety sausage when I dive. I might get around to putting on a bladder, but boy does this pack nice without it. I am all packed up to hit Little Cayman this week with the ScubaBoard Surge! I can't wait.

 

[axluba]

I would tell you were I was in 1969 but it would be indecent

I think it’s good for me to expend my view further than the OWD course (I love my instructor she’s great)! But at least I can realize that there is something behind my rental bcd.

 

[johndiver999]

On scuba, I prefer to breathe as efficiently as possible (a little slow and with a more complete exhalation than on land). I think this is best for me and also allows engagement in a higher workload (for short periods) without getting too stressed.

I can use lung volume to rise up and sink down for quick "excursions" that might last 20 -30 seconds or something, but otherwise I do fine tuning with the BC.

I try to prioritize efficient respiration and to avoid CO2 build up as much as is possible, rather than put too much effort into artificially manipulating the respiration cycle in order to avoid tapping a button on the BC. I find it uncomfortable to try to keep the lungs really full or really "low" during the respiration cycle. It increases the relative dead air space and I find it stressful for any period of time and it really limits my ability to swim, for example.

I've been presented with this situation a few times when at a safety stop and find myself too light. I end up trying to breath while keeping my lungs uncomfortably low. It does not make me feel good - so I try to always have enough lead. I pretty much never dive without a BC.

 

[60plus]

In saltwater I dive with 6 kg in my BCD integrated pockets and 6 kg on my belt with the weights well to the front. I find this gives me god stability (constantly correcting poor stability "burns" air) and I can slide the weight belt towards my head or feet to adjust my trim.