Air 'conservation'

[TheRedHead]

Charlie, I'm not sure, but it is true. A mental thing perhaps. With the Aluminum 80, the thinking is postively buoyant when empty so they load on a lot of extra weight to compensate for it and when their wetsuit compresses and they add a bunch of air to the BC. Then they forget to dump that air and cork.

On the other hand, the word "steel" encourages them to take off lead and dive with a minmum of air in the BC. And you need less weight to descend which is another reason people load on extra lead.

It's a psychological effect rather than one accounted for by physics. But, true nontheless.

 

[Jim Lapenta]

Agree with rhm. I personally do not dive with al if I can help it. I own 2 pst steel 80's usually pumped to 37-3800psi and 3 steel 72's that have not seen a fill below 3200 since I've owned them. I'm a little concerned cause I'm going to key largo 1st week of may and all the op uses are al tanks. I'm gonna have to get in the water with one before I go to get an idea of weighting cause I haven't used one since AOW which is about 70 dives ago. And I've been dropping weight regularly with the steel as I get better at this stuff. Last dive before going dry for the season was in a new 5 mil that I'd not dove before with a steel 72 and i only needed 10 lbs and was good all thru the dive including the safety stop with 400 psi left in the tank. Freshwater now so I know salt would require more but not that much more. Don't think I could do that with an al tank. BTW first dive on vacation will be the Duane ! Think I'm gonna borrow a tank when I get there and get weighed out in the lagoon before that tho.

 

[Miss Mollusc]

Sorry, didn't mean to sound grouchy, and yes, it comes up a lot. A good SAC comes with time and practice and if you are using more air right now, then bring more. There is nothing about the AL 80 that I like in recreational diving. I think the current rental fleet of AL80s should be destroyed and replaced with the beautiful E7-100. Then most of the newbies would run out of time before air and they wouldn't cork so much on their safety stops.

It's just an aluminum abomination.

You didn't Hmm, must hunt out this E7-100!!

 

[PaulChristenson]

Hi,

I'm relatively new to diving (<15 dives) so I'm a bit green - but I have a bit of a query regarding air usage. My delightful friends refer to me as 'air pig' as we have to cut dives short because I go through my tank twice as fast as the rest of the crew. I'm calm and relaxed but still seem to have to take very deep breaths. Any tips on er..air conservation? I'm small too, so it's not like I have elephant lungs!!

Thanks.

Aerobics for what ails ya....

And if you are in shape...then VISUALIZATION Exercises...
"Beeee the Diiiiverrrr"


Paul in VT

 

[neophyte]

I'm very new to diving also and started out as an awful airhog. I'm finally starting to improve and can personally attest to the fact that everything posted so far is true. Just keep diving and your consumption rate'll improve largely on its own. Using your hands less certainly helps, as does using larger tanks for the time being, that's how you'll get more bottom time and therefore more practice. Also, your buddies won't get so annoyed at you cutting their dives short

There is one thing I'd like to add that I haven't seen mentioned. The more dives I can get in on one day, the more I seem to improve. In other words, four dives in one day seems to improve my SAC, trim, bouyancy and everything else more than the same four dives spread out over two or three weekends.

That's all. Dive safe and have lots of fun.

Thanks for reading,
Adam

 

[Miss Mollusc]

Aerobics for what ails ya....

And if you are in shape...then VISUALIZATION Exercises...
"Beeee the Diiiiverrrr"


Paul in VT

yeah ta for that

 

[Miss Mollusc]

I'm very new to diving also and started out as an awful airhog. I'm finally starting to improve and can personally attest to the fact that everything posted so far is true. Just keep diving and your consumption rate'll improve largely on its own. Using your hands less certainly helps, as does using larger tanks for the time being, that's how you'll get more bottom time and therefore more practice. Also, your buddies won't get so annoyed at you cutting their dives short

There is one thing I'd like to add that I haven't seen mentioned. The more dives I can get in on one day, the more I seem to improve. In other words, four dives in one day seems to improve my SAC, trim, bouyancy and everything else more than the same four dives spread out over two or three weekends.

That's all. Dive safe and have lots of fun.

Thanks for reading,
Adam

Well all that's said, I think it's mostly due to the fact I'm about as skittish as a snapper. I'm so darned excited to be there I'm paddling there, reaching for that, peering under this, have tendency to have giggling fits through my reg...that combined with inexperience, there goes my air!

 

[Brewone0to]

JimLap
Add about 5# for the al80
locate it near the base of the tank
this should work out just about perfect

If you want you could use a clip-on trim weight and leave it on the anchor line.
As it is only needed when tank is empty(Because the al80 does get positive)

 

[Charlie99]

Aerobics for what ails ya....

I don't know if it's the same for others, but I find aerobics or general physical shape doesn't change my resting or loafing-around-the reef SAC. Being in good aerobic shape does keep down the natural rise in SAC that results from heavy finning.

 

[Charlie99]

If you want you could use a clip-on trim weight and leave it on the anchor line.
As it is only needed when tank is empty(Because the al80 does get positive)

This would be even more useful for the E7-100, which gets 8 pounds lighter during the dive. The AL80 only gets 6 pounds lighter. The real answer is to get your initial weighting right.

----

Not knowing which of the several versions of PST 80s or which steel 72s Jim is using makes it difficult to know how much weight he should be adding. If it's the 3500psi PST 80, then the adder is about 8 pounds when changing to the standard AL80.