How to reduce a monstrous SAC

[beaverdivers]

Since the force required to move against water resistance is proportional to the square of the velocity of the object, the work you are doing to swim goes up very fast as you move faster. (Note that streamlining your body and your gear will help with this, but only in direct proportion, rather than geometric.) When you are getting down to the fine-tuning stage, you really want to reduce ALL extraneous motion, and reduce drag as much as possible.

As you point out, a diver wants to reduce as much drag as possible.

HP hoses cause drag!

Using a Galileo sol eliminates the HP hoses, so you are more streamline!

 

[Hatul]

Just wanted to add a bit on being careful of CO2 retention. I'm early 40's, about 6'1", 275 lbs, kind of a semi-sedentary sort, not in great shape. Diving in the Caribbean, my SAC is around 0.75 (varies either way).

On a 2 tank boat dive trip one day on a cruise stop in Grand Cayman, I used skip breathing (which people hear warn you against) on the first dive, to extend my bottom time. It did help somewhat. It also left me with a headache so intense I almost called the 2'nd dive (thankfully it eased off enough over the surface interval so I didn't miss what was a fine dive!).

Years ago in professional training, the first time I entered an operating room to observe (note: I am NOT a surgeon!!!), I watched a feeding tube placement. Got sleepy, sort of swaying back & forth on my feet. I was really embarrassed thinking I was just inexplicably sleepy. My vision started losing focus. The Physician doing the surgery explained that I was rebreathing CO2 because of the mask over my face, & had me go sit against a wall without the mask. Soon, both my hands/forearms felt like I was holding one of those vibrating aerators people used to use to blow bubbles in fish aquariums. Very distinctive experience.

My point is, while I applaud a serious effort to enhance air efficiency and extend bottom time, be careful. I think some of this stuff can slip up on you if you're not careful. You don't want to stay down the rest of your life...

Richard.

It's not really important for this discussion, but the episode you describe in the OR sounds like a vaso-vagal episode, commonly known as a simple faint, though in your case you did not lose consciousness. It's doubtful breathing through a surgical mask can cause CO2 retention to cause symptoms, though it can cause anxiety in some people. If surgical masks were causing symptomatic CO2 retention all operating room personnel would be hyperventilating and would not able to function.

 

[ajduplessis]

Learn to meditate or start yoga. If you really want to improve your SAC you will have to give this a go. Swimming also helps but the main thing is that you need to learn to slow down your breathing rate and still fell comfortable.

I use a simple slow and deep 6 second inhale, a 2 second pause and slow and deep 4 second exhale as a breathing base. This gives me 4 effortless breaths a min and a low sac without getting headaches or retaining co2. Even 3 breaths are easy to maintain if you don't have workload like on a drift dive. Practise

 

[drrich2]

Hatul:

Interesting thought. I've been around blood & guts (e.g.: grew up around deer hunters) enough that such things don't bother me much and I don't know what would've triggered it. On the other hand, with my allergies I seem to have some chronic low-grade nasal airway resistance (thank you, Flonase!) and wearing a surgical mask in an O.R. used to mess with me (haven't had to do that in many years) - I'm 'hot natured' and between being warm enough to sweat some and breathing with resistance, I really, really didn't like operating rooms once I got past the 'neat' factor when it was a novelty.

I point this out to illustrate that my response to wearing surgical masks in the O.R. was different than most (& I battle skinny people over thermostats!), though I've never had an episode like that first one again. So not recurrent and I never passed out.

Richard.

 

[Jill from Phoenix]

Who are these women that are fat weighing 132lbs? Are they 4'9"?

 

[vladimir]

Furthermore, due to the fact that you are getting rid of the High Pressure hose(s) you are more streamline.

You know, I'll buy this just a little bit with regulator hoses, which tend to loop out away from the diver and sit in the water where they cause some drag. But the HP hose routes downward, along the diver's body, and perhaps up under the arm to be clipped off on a d-ring if the diver has a console he wants to secure that way. I don't think HP hoses cause any significant drag at all, unless they are ridiculously too long.

I agree, and what minimal drag a high pressure hose causes cannot be very different from the drag a transmitter on the first stage adds. But let's not let common sense get in the way of a heavy-handed sales pitch:

beaverdivers has the Galileo Sol for sale! It'll streamline you, in addition to all of its other amazing capabilities! PM him for a price!

 

[vladimir]

Who are these women that are fat weighing 132lbs? Are they 4'9"?

No, they can be 5'7", maybe even taller. In the States they're called foreigners.

 

[jcfahy]

I am conscious of monitoring my depth and not lingering at greater depths than useful to prolong my dive time

 

[waterpirate]

Besides the zen advice I would add, it is what it is. What is your lung capacity? Giveing your height and weight is really not the whole story. I am 6 feet and 190 with 34 inch inseam. My sac rate is low. My buddy is 6 feet 210 and has a inseam of 28 inches. His sac is high. The bottom line is that the shear size/volume of his lungs may be twice mine based on torso size. It was never measured, but makes sense. My advice is to relax and dive and gas plan accordingly.
Eric

 

[Jill from Phoenix]

No, they can be 5'7", maybe even taller. In the States they're called foreigners.

I was thinking they were called supermodels. Those american models are too fat to dive, no way they're sinking.