Extending bottom time with AL80s

[iztok]

I have half a dozen of AL80 tanks and a BC (Aeris 5 Oceans) that can't do doubles. So without investing a lot of money I was wondering what is a viable way to get best out of what I have for the deeper (80-130ft) dives?

I was thinking to make a sling for one of the AL80 and use it as a traveling bottle to get me down and up and one on my back to do exploring on the bottom.

Would that make any sense or am I just barking up the wrong tree?

 

[mike_s]

depends.... what mix you gonna put on your back and in in the "travel bottle" for what depth?

 

[scubafanatic]

I have half a dozen of AL80 tanks and a BC (Aeris 5 Oceans) that can't do doubles. So without investing a lot of money I was wondering what is a viable way to get best out of what I have for the deeper (80-130ft) dives?

I was thinking to make a sling for one of the AL80 and use it as a traveling bottle to get me down and up and one on my back to do exploring on the bottom.

Would that make any sense or am I just barking up the wrong tree?

...so, AL80's suck......but you bought 6 of 'em ??? ...trade 'em in for a couple high capacity steels.

 

[iztok]

depends.... what mix you gonna put on your back and in in the "travel bottle" for what depth?

Well I would use both at the same mixture for appropriate depth.

 

[bamamedic]

Hmmm....I can't think of any real reason not to...but there are a few things to consider.

You might be woefully lopsided with an 80 on your back and an 80 slung. I've started slinging an 80 when in doubles, and I can really feel the buoyancy swing of that 80, to the point where I have to compensate for it in my kick.

That much gas, at those depths, might push you past NDL. Something you'll have to pay close attention to...

Have you thought about selling a few of those 80's and purchasing a used steel cylinder instead?

 

[iztok]

...so, AL80's suck......but you bought 6 of 'em ??? ...trade 'em in for a couple high capacity steels.

Well 6 AL80s get me through week of local diving w/o going to the shop to refill them every day.

 

[Jim Baldwin]

I have half a dozen of AL80 tanks and a BC (Aeris 5 Oceans) that can't do doubles. So without investing a lot of money I was wondering what is a viable way to get best out of what I have for the deeper (80-130ft) dives?

I was thinking to make a sling for one of the AL80 and use it as a traveling bottle to get me down and up and one on my back to do exploring on the bottom.

Would that make any sense or am I just barking up the wrong tree?

You're looking at slinging one 80 and wearing the other 80 on your back both filled with air. Yes this would work. Breathe down both tanks and stay within no deco limits. You're going to have a bit more task loading.

If you don't want to invest in a BP/W, manifold, and an extra regulator and set your
80's up for doubles then consider selling your AL 80's. Use that money to put toward a couple of high capacity steel tanks.

A single 120 steel tank be it HP, LP or mid pressure will hold 50 percent more air than a standard AL 80 and you only need one regulator, one SPG and you can continue to use the BCD that you have.

My steel HP 100's and 120's have worked great for years. I have two AL80's that I have set up for sling tanks with 50 and 100 percent O2 that I use when I'm diving doubles for deco.

 

[iztok]

Hmmm....I can't think of any real reason not to...but there are a few things to consider.

You might be woefully lopsided with an 80 on your back and an 80 slung. I've started slinging an 80 when in doubles, and I can really feel the buoyancy swing of that 80, to the point where I have to compensate for it in my kick.

That much gas, at those depths, might push you past NDL. Something you'll have to pay close attention to...

Have you thought about selling a few of those 80's and purchasing a used steel cylinder instead?

I understand the NDL limits (my D9 is fairly conservative and Veo 180 is my backup) and idea is to use the same mix so if anything would go wrong with either I can breath the other.

 

[ianr33]

Yes it makes sense but I would suggest treating them as independent doubles/sidemounts.Start breathing from the stage tank.When it gets down to 1500psi switch to the back mounted tank.When that is at 1000 go back onto the stage. You should be back on the surface before the stage is empty.

Only need to do 2 reg changes and you get lots of redundancy. Make sure to always have enough gas in EACH tank to make a slow ascent in case of any gear issues.

 

[iztok]

If you don't want to invest in a BP/W, manifold, and an extra regulator and set your
80's up for doubles then consider selling your AL 80's. Use that money to put toward a couple of high capacity steel tanks.

Well I do have 6 AL80 so I don't have to run to the store to fill them in for a week during my local diving at the quarry (usually 4+ used over week).

I do have 19cf pony with regulator set already. So really with exception of making a sling for 80cf my investment is rather minimal.

Yes it is a bit of task loading as I would have to breath down both about equally. But my first idea was just to use it descending down the anchor line, leave it at the bottom, do the dive and return to the anchor line and use sling bottle for travel up.