THE "PERFECT ( being horizontal ) TRIM" HOAX

[scubadada]

@dumpsterpurrs,

I'm not sure everyone determines SAC rate (RMV) the same way. (So, not everyone is talking about the same thing when they refer to SAC rate, I think!) I learned to determine SAC rate(s) for dive planning a very long time ago using the following approach: Wearing the gear you intend to use for the upcoming dive, drop down to 20 ffw or so, get neutral, swim--fin--horizontally for a few minutes using your usual slow finning pace, and reverse course and fin back to the start. Using your cylinder pressures from the start and end of your "swim" for your particular cylinder(s), and your elapsed swim time (and the depth of your swim), compute your SAC rate.

Obviously, you'll compute different SAC rates for different gear configurations.

And the SAC rate you compute using the above approach is your working SAC rate. Your resting SAC rate (e.g., your SAC rate when you're comfortable, in calm seas, hanging onto the down line at your 20 ffw safefy stop) will, of course, be different than your working SAC rate.

FWIW, your best 6.4 L/min (= 0.23 ft^3/min) SAC rate is well below even my best resting SAC rate when I was in my best shape for diving, ~35 years ago! (I am male, 6'2", and I was ~230 lbs ~35 years ago.)

rx7diver

Hi @rx7diver

The poll asks for average RMV, that would be for the entire dive in a variety of circumstances.

For example, I have my RMV for 1,976 dives over 15 years under all kinds of diving conditions, water temps from 47 F to the mid 80s, 3-7 mm full suit with or without hooded vest, 8-20 lbs of weight. These are all rec dives, many solo, and about 5% light deco. My RMV has decreased very modestly during that time and the variation has become a little less. My average RMV is 0.36 +/- 0.04 cu ft/min (std dev) and my range is 0.24-0.63 cu ft/min. So, about 95% of all these dives have an RMV of 0.28-0.44 cu ft/min. I have a very good idea what variables raise my RMV, exertion, being cold, mental stress.

 

[Blackcrusader]

Today had some really enjoyable dives. Was in the verticle position for most of this dive.
Those down below were on a wee slope looking up and that position is a good one for observing.

Watch this video to the end. Tiger shark sweeps close to the guide then closer to me. There are sometimes strong currents at this site swishing the divers below left and right. Does get a bit crowded when big groups come in.

Yesterday a guy with the large camera rig you can see was told to stop using his strobes on the threshers and tigers and other sharks. So he doesn't listen and with one Tiger takes a photo and the strobes go off. The Tiger turned and charged at him banging into his camera rig.

Today he did not use his strobes with the sharks.

 

[Blackcrusader]

What trim is best when you can be hunted by an apex predator?

 

[chillyinCanada]

What trim is best when you can be hunted by an apex predator?

I'm surprised that worked.

 

[Blackcrusader]

I'm surprised that worked.

Yeah you never know what may work lol