MacDive Forums

On a recent trip I found I was using metric tanks that had no counter parts to US tanks. So it would be nice to have metric tanks where you just enter the water capacity and it calculates out the SAC/RMV rates based on the pressure.

I only ever use tanks in metric and it works fine for me.

I have 5L, 7L, 10.5L, 12L, 12.2L, & 15L defined and choose the one(s) for the dive.

ManateDiver wrote:On a recent trip I found I was using metric tanks that had no counter parts to US tanks. So it would be nice to have metric tanks where you just enter the water capacity and it calculates out the SAC/RMV rates based on the pressure.

Hi there,

SAC/RMV should be displayed correctly with only a volume if you are using Metric units - working pressure is only required if you display in Imperial. Is your issue here that you normally display in Imperial units, and you are trying to enter data in Metric and have it display?

If so, there's no way to do this - the units are application wide, not specific to bits of data. Can you just approximate it, if you need to convert it to imperial? I'm not quite clear on the specifics here, so I'm kind of guessing.. does this help, or could you clarify the issue a little further?

I am US based so everything else is setup in Imperial. But was overseas diving metric tanks.

Yes I was able to approximate it later, but would've been nice to be able to just have an option to enter the tank's metric volume, and it works out the cuft. And perhaps vice versa for metric folks diving in the States/Caribbean.

It is quite easy to calculate.

Take the volume in litres and multiply by the working pressure in bar. This gives you the number of litres of gas in the tank when full. Multiply this by 0.0353 to get cuft.

So a standard Faber tank is 12.2L and 232 bar so:
12.2 x 232 = 2830.4.
2830.4 x 0.0353 = 99.91312 which is close enough to 100 cuft.

AL80 is 11.1L and 207 bar is 81.10881 cuft.

Of course, metric is more accurate.

ATJ wrote:It is quite easy to calculate.

But it still requires someone to exit the program, have to calculate it out, and then create a new tank.

Since the program already has to do the math for metric tanks, I was putting in a feature request of having the ability to use the other system for defining tanks for traveling divers. I understand if it is back burnered or even rejected as TBH most travel divers are diving the common AL80, but it never hurts to ask.