How to Communicate Air Level

[cbborromeo]

There was a thread about this a long while back. As you found out, there is no consensus on this and the DM should communicate his/her preferred method during pre-dive briefing. HOWEVER, many folks prefer the one handed signals that is used by the Navy SEALS, Coast Guard Rescue Divers, pilots, etc.

I have a handy visual from Advanced Diver Magazine. If I get permission from Curt bowen of ADM and figure out how to post it, I'll be happy to share.

 

[Charlie99]

Obviously it is important to have agreed ahead of time. The various systems I've encountered include:

1. Show the gauge

2. 1 finger per 100psi, repeated groups of 5 on one hand.

3. Same as 2, but using both hands.

4. Sequentially doing thousands, then hundreds, using two hands.

5. Sequentially doing thousands, then hundreds, using just 1 hand.
1 to 5 is fingers vertical, 6-9 is with fingers horizontal.

6. After reading some other posts in this thread, I realize that one instabuddy did the "thousands on the forearm, hundreds on the fist" method, I just didn't know it at the time and swam over and read his gauge.

Other signals include
"timeout" sign for half a tank (or 100 bar).
A closed fist for out of air, also sometimes for 50 bar

Then the other general method ---
agree upon ascent and turnaround pressures and when you hit that point, give the appropriate signal.

Part of my standard insta-buddy briefing is that I use 1 finger for every 100psi (or 10 bar), showing repeated groups of 5 using only one hand. Slow, but very intuitive and easy to brief and understand.

 

[Guba]

Two good methods that require a minimum of movement and only one hand:

1) A tap on the forearm is 1000...holding up a fingers is a hundred psi a finger. So, the fellow who tapped his arm and held up three fingers was showing 1300 psi.

2) An easier way comes after understanding how to communicate small numbers under water. Each finger held up vertically is 1, up to five. Then point horizontally (the same fingers) for 6, 7, 8, 9, and 10. (see www.scubadiver.cc/handsignals/uscommunications.htm for video examples)
Okay, so for reporting air, forget the hundreds. Simply sign the first two digits of the air you want to report. 2200 pounds is 2...2. (two fingers held vertically, twice) Eighteen hundred is 1 (one digit vertically) and 8 (three fingers held horizontally).
Quick, easy, and easily understood ASSUMING that both divers in the communication loop know the system beforehand.

 

[MXGratefulDiver]

That's a very good question to ask your dive buddy before you get in the water. I've seen at least four different ways to do it.

Discuss what signals you will use as part of your pre-dive routine, to make sure you'll understand each other.

Showing your gauge or AIC is often not effective, as ambient light or lack of familiarity (with a given model of computer) may make it difficult for your dive buddy to read ...

... Bob (Grateful Diver)

 

[nagel]

Thanks for all the input. I'm relieved to know I didn't sleep through something in class. On the way home, my "normal" buddy and I talked about this. We have our signals (5's), but diving with "instabuddies" created this miscommunication issue and neither of us was aware of any "standard" way of doing this - thus the question to the experts here.

Thanks,

S. Nagel

 

[Guba]

Man, talk about redundancy! What did we all do, have a conference call and then send in at the same time? Three of us sent in essentially the same method with the same time stamp on it!
Quick typing, ya'll! lol

 

[diver 85]

Kinda a stupid question, but you know what they say - there is no such thing. While under water, what is the standard way to communicate your air level? What I mean is, say you're buddy signals that they want to know how much air you have left. You check and you have 1900psi. How would you communicate this short of showing them your spg?

I was on a dive recently doing some training with about 5 other divers that I had never dove with before; so, we didn't have any clear cut signals for this. The instructor went around to everybody signalling "how much air do you have left". Some of the other divers tapped on their arm and then held up fingers (not sure what this meant). Others, tried to signal using their fingers - such as for 1900 they held up 1 finger and then 9 fingers.

Seems like something simple, but I was confused and forgot to ask after the dive.

S. Nagel

In this case, I would make a circle around my SPG with my index finger then count out 1,9 for 1900....That would be my index finger only pointing up(for the one in 19) then index, middle,ring, & pinky all pointing sideways @ one time(for the number nine in 19)....That would indicate the number nineteen, short for the number 1900....note, you could always make to small circles meaning the 2 zeros in the number 1900 but I usually don't, most will understand 19 for 1900)........


Now if it were for an even 1000, 2000, or 3000 psi, I would(let's take the case of 2000 psi here) lay my index and middle down together across my forearm indicating 2000 lbs left, no multiple finger counting needed, ie much easier.......(3000 would be ring, middle, and index---1000 would be index finger only)......

 

[El Orans]

While on Bonaire, we dove a lot with American divers (psi), we're strictly bar though.

We got around this by using "quarts". 750 psi equals 50 bar, so when asked we'd just indicate 1/4, 1/2 or 3/4. Worked like a charm.

 

[Charlie99]

While on Bonaire, we dove a lot with American divers (psi), we're strictly bar though.

We got around this by using "quarts". 750 psi equals 50 bar, so when asked we'd just indicate 1/4, 1/2 or 3/4. Worked like a charm.

That's good enough for car fuel gauges, so I guess that ought to work for scuba too.

Typically I request gas pressure info for only two reasons

One is when I'm leading and want to compare SACs in order to better organize the dive, such as whether or not to head out towards a specific point of interest or spend time at a different place. For me at least, what works best is to note starting pressures, and then check again at about 3/4 tank. The 1/4 tank resolution isn't going to work for this purpose.

The other reason I inquire about SPG reading is when I suspect that my buddy is approaching or has gone past an agreed on point such as turnaround pressure or ascent pressure.

For either of those purposes, I find the simplest, most foolproof method of exchanging signals is 1 finger per 10 bar. Before the dive, we agree upon turn pressure and rock bottom in both psi and bar.

Most of my diving is with AL80 / 11l 207 bar tanks. The only conversions needed are
70 bar per 1000 psi (so 35 bar per 500psi) and full tank is 200 bar (so half tank or 1500psi is 100bar, and quarter tank or 750psi is 50 bar).

 

[RonFrank]

Agree on the method to use prior to entering the water.

I generally don't monitor other divers air. If I'm with a buddy that I know uses more air than I do, I will sometimes ask if they are OK by just pointing at my SPG, and than asking for an OK.

In general however we just set limits, and then follow them. IOW's maybe we say Max Depth X, max time at max depth Y, turn pressure is Z. First one to Z signals an ascent, or we start the ascent when we hit max Time at depth. This makes the assumption you trust your buddy to monitor their air!

It also depends a bit on what one is diving. If boat diving shallow reefs or even deeper sites generally I run out of NDL, or allotted time, before air.