Imperial users abroad?

[Lorenzoid]

Ideally I'd get everything in metric, but if I'm diving stateside, I want to be on the same page as my fellow divers -- I don't want to have to convert anything in my head underwater, if someone asks for my gas levels for example.

Great recommendations given by others.

I would add that what's most important is that YOU monitor your own gas and act accordingly. Now, if you find yourself faced with diving with an unfamiliar buddy or divemaster, you can let them know beforehand that your gauge reads in psi and that if they ask you for your pressure, your response will be in psi (and explain what signals you use for the digits--that's something dive buddies should always make sure they are on the same page about).

If you are diving with a paid professional divemaster, the divemaster should accept that part of that role is dealing with the inevitable American visitors whose gauges read in psi. When I was diving in Honduras, my group included both Americans and Europeans, and I recall the DM saying it was okay for us to reply using either bar or psi, and we worked out how we would do that.

If you are diving with an unfamiliar buddy--that is, someone with whom you have no relationship except that a little while before the dive you agreed to buddy up with each other--there is really no necessity for such a buddy to ask you for your pressure, since it's your responsibility to monitor your own gas. You and your buddy may or may not want to agree before the dive to ask each other your pressures during the dive. Absent such a prior agreement, an experienced diver who has sadly forgotten what it's like to be a new diver might feel his ego bruised by a newbie asking him for his pressure. Most typically, you will agree to just signal each other when you reach half your starting pressure, as someone else pointed out. If and when your gas gets "low" (whatever that may mean to you), you signal to your buddy that the dive is over and it's time to ascend.

 

[agilis]

I monitor my own depth, gas supply, and other relevant parameters. I do not understand why it would matter in the slightest that other divers were using different numbers on essentially the same gauges.

 

[Freewillow]

the signals for turn around and half tank are universal

Universal, I wonder. What are they for you? I know at least two for half tank and none for turn around .................except that we normally turn around @ half tank, except if otherwise agreed with partner

 

[Centrals]

It doesn't matter!
Who is reading your gauge anyway beside yourself?
As for hand signal, I thought it has to be agreed before hand.

 

[runsongas]

circular finger twirl for turn around, T with two hands for half tank? never seen anyone do it differently.

 

[KevinNM]

If you plan to do a lot of overseas dive travel, at least get a dual unit SPG: ScubaPro Dual Scuba Pressure Gauge - SPG in Metric and Imperial | SPG

I have that and it's hard to read when actually diving. I moved it to a pony. If anyone has larger diameter one with larger/clearer markings without the stupid color code stuff I'll be willing to try again.

 

[JohnnyC]

I've never had a problem. Just remember that 35 bar is pretty close to 500 psi, 50 bar is close to 725 psi, 140 bar is close to 2000 psi, that's really all that most DM's are looking to see. You should be watching your own air anyway, and in most places, just giving an "ok" signal is good enough for most DM's provided you are a demonstrably competent diver.

Interestingly enough, I've found giving numerals in hand signals as opposed to the arm thing is sufficiently confusing to most DM's that they don't bother asking after the first time.

 

[Centrals]

Interestingly enough, I've found giving numerals in hand signals as opposed to the arm thing is sufficiently confusing to most DM's that they don't bother asking after the first time.

Especially counting beyond five with one hand.

 

[drbill]

The conversion to bar is pretty simple as Pete suggested. I travel to many places that use the metric system but I still use my imperial unit gauges with little to no trouble

 

[Kevrumbo]

For those with imperial gauges, what do you do when you go abroad? Do you swap it out with a set of metric gauges, or do you just do on the fly conversions when talking to local dive buddies/DM's/etc?

Easy, quick & approximate conversions to practice, especially if you are buddied-up with a lot of European or Asian Divers over the course of an overseas dive vacation:

Pressure Bar multiplied by 3/2, and multiplied again by 10 gives Pressure PSI;
Pressure PSI multiplied by 2/3, and divided by 10 gives Pressure Bar.
Example:
Full 11L/bar (AL80) Tank: 200bar(3/2)(10) = 3000psi ; 3000psi(2/3)/10 = 200bar.
Half Tank: 100bar(3/2)(10) = 1500psi; 1500psi(2/3)/10 = 100bar.
"Be On Surface": 40bar(3/2)(10) = 600psi; 600psi(2/3)/10 = 40bar

A full AL80 tank at 3000psi has a volume of 77 cubic feet. In Metric, this is called an "Aluminium Cylinder" rated at 11 Liters/bar with maximum 200 bar pressure and 2200 liters volume.

The common counting numbers, or Reference Cardinal Numbers, for depth seen in most Dive Tables are approximate sequences like:

Imperial US (feet) denoted by intervals of 10:
Ex): 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110 etc

Matching the above, Metric System goes by 3's:
Ex): 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33 etc

Practice the depth conversion factors above ("3/10" and "10/3") between the two number sequences. . . So 18 meters x 10 feet/3 meters = 60 feet
And 60 feet x 3 meters/10 feet = 18 meters.

Any "in between" number like "75 feet", just round it to the next deepest number (80 feet), and do your conversion: (80)(3/10) = 24 meters.
Another example, 31 meters round it deeper to 33 meters: (33)(10/3) = 110 feet.

To get a "visual idea" of what a depth of 10 meters looks like, just imagine the length of 10 yards on an American Football Field (10 meters is around 11 yards). So be aware that a value like 50 meters is very deep -roughly half the goal-line to goal-line length of a Football Field. So obviously 50 meters is not the equivalent of 50 feet!!

Deg C to Deg F: just double and add 30. So 25 deg C converts to 80 deg F (a little bit more than the actual value of 77 deg F, but a good approximation).
Deg F to Deg C: subtract 30 and take half. So 90 deg F converts to 30 deg C.

1 kg is 2.2 lbs; 10cm is approx 4 inches.