Advantages to Imperial units

[UFOrb]

When my buddy asks how much gas I have, I don't have to do some crazy hand flashing, counting, cross handed sign language. I just hold up one hand, and show the number of Jeffs. There's a reason humans invented a base-10 number system. Now divers can use the even more handy 5 finger salute!!

I have wondered how you signal remaining gas in psi units, I'm now getting an idea. It'll be interesting if/when I get to dive stateside, could get confusing! Another advantage of metric, although still not as efficient as Jeffs (until you get down to 50bar)

 

[rivers]

I am from one of the three countries in the world that use Imperial units (feet, pounds, etc.) and I have found one advantage to this (apologies to Dr. Neil deGrasse Tyson).

My depth reminds me about how much air I should have to start my ascent, to wit:

When I have 1000 lbs, I start ascending if I am 100 ft deep,
When I have 800 lbs, I start ascending if I am 80 ft deep,
...etc... (I do not go deeper than 30m as a rule).

Now before you can say "depending on conditions", I totally agree this is assuming benign conditions below *and* above.

Now before you say "WHAT?!? Way too early!" -- I say: this is what works for me -- as a guideline, because I am a heavy breather.

Now before you say: "You gotta work on your air consumption, buddy", I say: Tell me something I *don't* know!

Now let the compliments, condolences, and criticisms roll in.

Have a happy.

- Bill

I'd say that's way too late to be ascending, but that's just me. How much gas do you need to get you and your buddy to the surface from 30m (100 ft)? Do the maths and then see if your 1000psi is enough.

 

[Centrals]

I have wondered how you signal remaining gas in psi units, I'm now getting an idea. It'll be interesting if/when I get to dive stateside, could get confusing! Another advantage of metric, although still not as efficient as Jeffs (until you get down to 50bar)

Hand signals have to be agreed before.

 

[JohnnyC]

Just remember, there are two types of countries, those that use the metric system, and those that have put man on the moon......

 

[UFOrb]

Hand signals have to be agreed before.

Yes, even with bar we go over hand signals beforehand, although they're generally universally the same. For psi I'm guessing there's more variation in the signals used?
My SPG is bar, so when I dive in the States presumably my guide/buddy would be/have to become familiar with those units, or I'd rent a psi gauge and I have to learn...

 

[Kevrumbo]

. .. .
My depth reminds me about how much air I should have to start my ascent, to wit:

When I have 1000 lbs, I start ascending if I am 100 ft deep,
When I have 800 lbs, I start ascending if I am 80 ft deep,
...etc... (I do not go deeper than 30m as a rule). . .

- Bill

For a reasonable attainable non-exerting rule-of-thumb SAC rate on an AL80/11L cylinder of a novice to experienced Diver, your depth in meters will roughly indicate how much you will consume in 5 minutes in bar pressure units -so for example, at 30m depth in 5 minutes, you will consume 30 bar of Air. [This approximately relates to a RMV of 17 liters/min, which is 0.6 cf/min in US Imperial]

So if you start the dive at 30m with a 200 bar 11L cylinder source of Air, all you need to do in keeping track of your consumption is an easy running subtraction of 30 bar every 5 minutes, and confirm it with a quick check of your SPG every ten minutes (or in this case because of deep depth of 30m on single tank, check SPG every five minutes). And so you expect the SPG to read 170 bar remaining after 5min elapsed dive time; and to read 140 bar after another 5min elapsed dive time; and finally a "Rock Bottom" Minimum Gas Reserve value of 110 bar after another 5min elapsed dive time for a total bottom time of 15 minutes at 30m depth.

Since you are a heavy breather Bill, the consumption value you should try is the depth in meters absolute -which is just adding an extra 10 meters to the depth gauge reading- so 30m gauge reading is 40m absolute. So at 30m depth in five minutes elapsed dive time, expect to consume 40 bar of Air instead.

The point is that in Metric units, it's much easier to account and keep track of your dive time and corresponding consumption rate waypoints as they approach your Rock Bottom final SPG reading. If the running consumption rate indicated by your SPG is 30% or more than you figured, then you have a leak somewhere or are physically breathing harder due to unexpected exertion or perhaps experiencing a medical problem, and probably should consider aborting the dive.

Lastly, consider using a dual unit SPG:
Extreme Exposure

 

[Centrals]

Just remember, there are two types of countries, those that use the metric system, and those that have put man on the moon......

Living in the past by Jethro Tull(1969).
First man on the Mars count! But I won't live to see that.

 

[UFOrb]

Just remember, there are two types of countries, those that use the metric system, and those that have put man on the moon......

Ha, you just have to be awkward! At least in the States you use imperial only though. We're now all over the place in the UK, with the older generation mainly familiar with imperial, the younger generation metric and us in the middle using both, imperial for some measurements and metric for others. Eg I use imperial for human height & weight, but metric for everything else (I think), including weight Oh yeah, we all use imperial for distance & speed on the roads. Edit: and how could I forget beer! we still drink pints.

For diving its metric all the way at least!!

 

[admikar]

Waiter, why are only 4 Jeffs of beer in my keg?
Legal question for European divers, can my c-card be pulled off if start behaving weirdly? Like using Jeffs?

 

[w3dge]

Ha, you just have to be awkward! At least in the States you use imperial only though. We're now all over the place in the UK, with the older generation mainly familiar with imperial, the younger generation metric and us in the middle using both, imperial for some measurements and metric for others. Eg I use imperial for human height & weight, but metric for everything else (I think), including weight Oh yeah, we all use imperial for distance & speed on the roads. Edit: and how could I forget beer! we still drink pints.

For diving its metric all the way at least!!

Because ordering half a litre of beer just isn't the same! At least you get to order a litre of beer in Germany, I suppose...