Why are AL80 tanks often refered to as 12L tanks (rather than 10L?)

[James79]

However, you do need more pressure than your reg's IP if I'm not mistaken.

The first stage only closes off the tank pressure when IP is reached.... breathing the tank below IP will just cause the second to breathe harder, but it won't stop giving air until tank pressure is down to ambient (hence a cesa with the reg in your mouth should actually allow for a breathe at some point on the way up).

 

[Diving Dubai]

Hmm I've booked 15lt tanks for a Bali trip, I was hoping they were going to be Faber steels like I use at home but then they said they were aluminium. Not too happy that they're actually 13.6lt.

The13l is worth an extra 30 bar over the AL 80. Up to you to decide if it’s worth it

Or just take SM rig

 

[stepfen]

Hmm I've booked 15lt tanks for a Bali trip, I was hoping they were going to be Faber steels like I use at home but then they said they were aluminium. Not too happy that they're actually 13.6lt.

Yeap, definitely not as good as real 15Lt, but better that the standard 11.1Lt. Back then I chose to use them (and pay a bit extra per tank). It was a good decision because it allowed me to follow the group till the end for most of the dives.

 

[Mike1967]

Or just take SM rig

Was going to do that but apart from being new to SM, that would cost me even more and I'd be bringing gas back every dive. I'll definitely stick with the 13s this trip.

 

[Mike1967]

It was a good decision because it allowed me to follow the group till the end for most of the dives.

Cheers

 

[Diving Dubai]

Was going to do that but apart from being new to SM, that would cost me even more and I'd be bringing gas back every dive. I'll definitely stick with the 13s this trip.

Fair point about SM

I’ve never been charged extra for a second AL80. I would rig it as a pony. Sometime heavy gas consumption can be caused by worrying about having a small cylinder. When I was away using an AL80 as a pony, I’d use mayber 30 bar out of it, and have 80 bar in my back tank at the end of a dive. Had I taken just an AL80 or AL100 (13l) I’d have been down to 30bar at dive end, just from “worrying” that I’d be the first person to surface due to gas consumption.

I take my SM everywhere now on trips, so never need to worry about gas.

 

[RainPilot]

Was going to do that but apart from being new to SM, that would cost me even more and I'd be bringing gas back every dive. I'll definitely stick with the 13s this trip.

That's fair. For two tank boat trips, you will find though that you get more gas from 2 x AL80 in SM than from the same 2 as single back mount. That can be a significant difference in some cases.

 

[Mike1967]

I take my SM everywhere now on trips, so never need to worry about gas.

Yeah this is my first diving holiday so I'm trying to keep it as simple as I can, once I get more experienced with SM I'll do the same.

For two tank boat trips, you will find though that you get more gas from 2 x AL80 in SM than from the same 2 as single back mount.

Are you referring to only needing one reserve at the end of the second dive instead of 2 when diving singles?

 

[RainPilot]

Yeah this is my first diving holiday so I'm trying to keep it as simple as I can, once I get more experienced with SM I'll do the same.


Are you referring to only needing one reserve at the end of the second dive instead of 2 when diving singles?

Yep. 30 bar extra (around 12 CF) on shallow dives and up to 100 extra on deeper dives (around 30 CF) in my particular use case.

Of course the caveat is that if you use that reserve on the first dive for a situation, then dive 2 may no longer be doable.

 

[Mike1967]

30 bar extra (around 12 CF) on shallow dives and up to 100 extra on deeper dives (around 30 CF) in my particular use case.

I dive to a 50bar reserve so I'de only gain that, how do you get a 100bar gain?