How do you signal air remaining?

[Charlie99]

I always have my divers signal on one hand. 1300=5+5+3. I have found it to be the least confusing method for everyone. But, you have to keep in mind we are all a little bit slow in the Caribbean.

This is the simple method I use when diving with insta-buddies. Easy to brief. ("1 hand. 1 finger for each 100psi.") Easy to use. Since we only exchange signals once or twice in a dive, simplicity is more important than speed.

Swim over and grab SPG if there's any doubt.

On most dives the only pressures of interest are the agreed upon turn and ascent points, so SPG readings aren't needed.

Where it DOES help to exchange SPG readings a couple times is on dives where you are wandering around a reef, then headed back to shore or anchor line. Knowing my buddy's consumption rate helps me pick an intinerary best suited for the length of time and gas left.

 

[Mike Veitch]

When i guide divers i don't care what they have until they get to 1000psi. Thats when i tell them to give me the finger.....whichever one they like....makes for humourous briefings

 

[Bo-jan]

In Europe we use different measuring units for pressure. A full tank is 200 bar (1 bar being about the equivalent of atmospheric pressure at sea level). I usually signal half a tank (100 bars, form a letter T like in time-out) and 50 bars (clenched fist). If I have to signal the remaining air at like 115 bars it's much easier just to show the pressure gauge.

Cheers
Bojan

 

[String]

If i only had a 200 bar fill in my tanks id be straight back to the fill station asking them where the other 32 bar has gone !

I thought only ancient aluminium tanks had 200 bar max pressure ratings.

 

[Bo-jan]

If i only had a 200 bar fill in my tanks id be straight back to the fill station asking them where the other 32 bar has gone !

I thought only ancient aluminium tanks had 200 bar max pressure ratings.

Most of us here dive with 15 or 18 liter steel tanks. 200 bar is just the declared pressure rating as I think most are tested on 300 bar to get the atest. I'm not 100% sure about this tho. Anyway, it is "good practice" to fill the tank to 220 bar which then cools down and you get effectively 200 bar out of it. Everything else is imho overkill as you increase the strain on the material and you decrease the life span of the tank and also the first stage of the regulator since it has to handle higher pressure. However, the dive center I was with on the island of Korcula in Croatia always filled the tanks to 220 bar net!

Cheers
Bojan

 

[String]

All the tanks ive seen here (99% are steel) are 232 bar working pressure (348 bar test). Most of my diving is with a 15l cylinder and id hate to ever see the type of diving that requires an 18!

The reason abroad 200 bar seems normal is the compressions are only rated at 206 bar maximum so are unable to fill a steel tank to its full working pressure.

 

[kidspot]

This is the simple method I use when diving with insta-buddies. Easy to brief. ("1 hand. 1 finger for each 100psi.") Easy to use. Since we only exchange signals once or twice in a dive, simplicity is more important than speed.

Swim over and grab SPG if there's any doubt.

On most dives the only pressures of interest are the agreed upon turn and ascent points, so SPG readings aren't needed.

Where it DOES help to exchange SPG readings a couple times is on dives where you are wandering around a reef, then headed back to shore or anchor line. Knowing my buddy's consumption rate helps me pick an intinerary best suited for the length of time and gas left.

I agree completely - around here with so many "unknown" buddies simplicity is a good thing. And since many dives are just cruising around the reef it's nice to know how long to plan for and if you can go to certain places or not once you are into the dive...

Aloha, Tim

 

[mark99]

All the tanks ive seen here (99% are steel) are 232 bar working pressure (348 bar test). Most of my diving is with a 15l cylinder and id hate to ever see the type of diving that requires an 18!

The reason abroad 200 bar seems normal is the compressions are only rated at 206 bar maximum so are unable to fill a steel tank to its full working pressure.

The AL tanks are rated to 200 bar working pressure plus an allowance for 10% overfill (hence Bo-jan's 220 bar fills). The steel tanks you are referring to are "high pressure" (HP) steel tanks, rated to 232 bar working pressure (no overfill allowed).

 

[String]

The AL tanks are rated to 200 bar working pressure plus an allowance for 10% overfill (hence Bo-jan's 220 bar fills). The steel tanks you are referring to are "high pressure" (HP) steel tanks, rated to 232 bar working pressure (no overfill allowed).

If you call a standard 232 bar steel tank "high pressure" what on earth do you call a 300bar steel tank?

 

[cool_hardware52]

99 Posts! Boy there is a truely frightening number of variations.

A couple points:

Signals................First Part of Predive Brief, do it! (Do the rest too)
Emergency
Activities
Buoyancy
Air
Gear

What I was taught, and what I do.... One handed Fingers Up, palm out for 1-5, Fingers sideways palm in for 6-9, circle all fingers, i.e. almost closed fist for zero (not the same as OK)

This method requires only one hand, no addition, and can be "backlit" in low light or vis.
(Failure to be able to do simple addition is a pretty interesting "nark" test.)

For SGP readings zero's are unnecessary. Thousands and hundreds only. Who's kidding who with a 1240 sign? Can you really read your SPG to +, - 10 psi? Even if you could, does it matter?

If somebody signals me a single digit of 3 or greater, I know it's hundreds. If I get a 1 or 2, it's gunna be 1000's.

What about the unknown newbie air hog who might be signaling 200 psi? You can tell who's the complete air hog, sucking down an al 80 to 200psi in 20 minutes. They look like a giant alka seltzer. These folks need to be bird dogged anyway. I'm not going to trust their signals in the first place.

For SPG readings, grabbing the gauge is always an option, but one needs to be able to communicate numbers UW for other reasons such as:

Compass headings

Depth

Depth and times (Safety stops, deco etc.)


Tobin