If you are a new diver, please read this

[LavaSurfer]

When you are freaked out at the surface as a new diver on your 6th opena water dive... you don't remeber to dump your weights or orally inflate your BC... especially if your BC is an airtrim model and requires more steps.

But you would if it was driven into you. In the pool, many many ascent are made and then completed with an oral inflation to achieve neutral buoyancy. No Student of mine is certified without Mastering this skill to a level that is beyond expected. Oral inflation both under water and at the surface should be a regularly practiced skill and especially important if you rent gear or change gear as you may have differences you don't want to discover in an emergency.

 

[Ursus]

I'm glad you learned a lot from your trip, but why in the world would you think a diver needed to buddy breathe at the surface? That sounds like a real danger, if the diver felt that this was necessary. This statement in bold, (possibly taken out of context) seems to represent an almost complete lack of watermanship skills, by both you and the people doing it. Thinking that buddy breathing at the surface is necesary is just crazy.

THe diver was a seasoned vetran who ran out of air while waiting rotation to board boat in 3'-5' waves plus current following a deep dive. He bingoed while on standby and apparently got a bit panicked. His BC was inflated, but at times hard to keep your head out of water due to waves. If he had a snorkel he probably would have felt a little calmer. I can only speculate that between open ocean, current, waves, no air, and multi tasking to get on the boarding rope, remove fins, and deal with other divers competing to do the same it was a bit overwhelming for him. He was assisted by a veteran diver. My point was that the unexpected happens and even experienced divers can become overtaxed.

 

[Blackwood]

Plus, it has the advantage of being in the format students are accustomed to, so it would be an inexpensive, non-invasive, uncomplicated addition to BOW curriculum which would put all divers in a buddy team on the same page.

e.g.

The back side could have conversions from volume to pressure for a variety of tanks.

 

[Rainer]

Yes, would probably want the other side to have conversions (maybe also list the tank factors so divers could do the calcs without ref to the chart).

I'd also likely highlight the 2.0 row as it's what many use for emergency planning (i.e. two divers both at 1.0 SCR). Could probably even do away with such fine grain distinctions in the SCR column.

Otherwise, nice table.

e.g.

The back side could have conversions from volume to pressure for a variety of tanks.

 

[Blackwood]

Otherwise, nice table.

Not bad for a 3 minute job (most of which was formatting).

But yah, it's just a suggestion to those (a minority in this thread, but not so in the wider world) who seem to think that teaching gas planning is overly complicated and math intense.

I totally agree you should keep your own life in your own hands and watch your OWN SPG religously, but if you got a spare minute and are close enough to check your buddy's....

And better yet, have an expectation of what it will say.

Why not just ask him?

 

[Rainer]

The gas management taught...
monitor your guages, know how much air your buddy has, begin your ascent when one of you has "x" amount of gas left, be back on the boat with no less than 500 PSI. (+-100 psi)
.

How are new divers being taught to calculate "X"? [Especially as relates to dives to different depths.] What are divers being taught "X" represents? That is, how is a diver to know what amount of gas to reserve such that he can actually get on the boat with 500 psi? And why 500 psi? How is that number being motivated? To me, gas management pretty much boils down to calculating and understanding "X" (i.e. rock bottom). If a diver can't figure out what the minimum amount of gas needed to get him and a buddy to the surface in an OOG emergency, he's conducting an unsafe dive. There's really nothing more basic than calculating the right "X".

 

[Jrock1062]

good read

 

[Rainer]

But there's the rub, many of us don't dive off commercial boats or have DMs to tell us these "limits". Seems worthwhile to take a few minutes to explain to a new diver how to calculate these number for himself.

If I'm doing a 30' shore dive, there's absolutely no reason to reserve 1200 psi. If I'm doing a 100' dive in an Al63 (no, I wouldn't do this, but PLENTY of divers do...), 1200 psi probably isn't enough of a reserve.

The point is, there's no need to pull "magical" numbers out of a hat. If anything, teaching new divers where these numbers come from is only going to reinforce better dive practices.

X is either 1200 or 1000 depending upon their depth (for tourist and most OW divers) and it is usually the number given them by the commercail dive boat during their briefing (Here in Florida)

See above

see above

I believe that is fantastic for a more advanced diver such as yourself. This type of calculation is taught in most Advanced Open Water classes

 

[Teamcasa]

I contend that it is not a key thing for students to learn in OW class. You have given no evidence to change that thought. ...

He won't.

The gas management taught...
monitor your guages, know how much air your buddy has, begin your ascent when one of you has "x" amount of gas left, be back on the boat with no less than 500 PSI. (+-100 psi) Is more than sufficient to keep new OW divers safe!

I contend you are giving them a needless excercise at the OW level when you could be "teaching" them important skills for that level... buddy, bouyancy... heck, even how to use their computer...

How are new divers being taught to calculate "X"? ... There's really nothing more basic than calculating the right "X".

Your do contend a great deal based on assumptions that you have no basis for making except your own paucity of experience.

Again, we are talking about brand spankin' new divers.

The Divemaster, staring into the wide eyed group of new OW divers begins his briefing.
"OK, we are at noname reef. The site is about 50 deep and we expect to see all sorts of cool stuff.
We will descend down the mooring line and head West until one of you gets to 1200 or so PSI. At which point, we will turn and return, make our stop here on the line. Check you air regularly and check your buddy's as well.
I will lead, the other DM, Suzi will follow. Again, check your gauges regularly and let us know what your air pressure is when we ask. Here is how I want you to show me your pressure remaining..."

X is what the DM says it is.

 

[BHB ScubaTroll]

But there's the rub, many of us don't dive off commercial boats or have DMs to tell us these "limits". Seems worthwhile to take a few minutes to explain to a new diver how to calculate these number for himself.

If I'm doing a 30' shore dive, there's absolutely no reason to reserve 1200 psi. If I'm doing a 100' dive in an Al63 (no, I wouldn't do this, but PLENTY of divers do...), 1200 psi probably isn't enough of a reserve.

The point is, there's no need to pull "magical" numbers out of a hat. If anything, teaching new divers where these numbers come from is only going to reinforce better dive practices.

All these areas were covered in the first OW class. They were the same numbers given by the instructors for the first OW class and they keep the vast majority of new OW divers safe.

I know that: on a 60-80' dive I can begin my ascent with 750 psi, do my safety stops and be on the surface with 500 psi using a steel 100 HP... There, calculations done

I know this because I do it over and over again.

I reserve more air when I dive deeper...