How long would the air last me in an average sized scuba tank?

Question

also, what would be the best size and how much would it cost?

Answer 1

It depends on how big your lungs are and what level of skill you are at. At the advanced course, you can pick up breathing skill to lengthen your diving time.

Normally no one buys tank because they are provided for free at dive centers unless if you are too rich.

Answer 2

The "standard" size is an aluminum 80 cubic foot tank. How long that will last on a dive depends on a few factors and as you'll see, can vary quite a lot from dive to dive and diver to diver.

1/ How deep you go. The deeper you go, the more air required for a single breath. Your regulator will deliver usable air to you at the ambient water pressure for the depth you are at. If it didn't, you wouldn't be able to breathe. As you descend, that volume of air ( your lung volume) stays the same, but the pressure needed to keep that volume constant goes up. More air molecules are packed into that same volume. Hence...you need more air per breath as you dive deeper.  

2/ How much you exert yourself. Just the same as on the surface, if you're working hard, you'll use more air. Especially so if you have a lousy kick style, aren't streamlined or aren't trimmed properly. All of those things will use air to deal with. If your buoyancy control sucks, you'll also be using air from that tank as you constantly adjust your buoyancy. That can be a quite a bit for some people.

3/ Is the water warm or is it cold? Cold water dives tend to use a little more air. You're breathing rate tends to climb a bit.

4/ The diver. If you're out of shape, you'll use more air. If you use your legs unnecessarily, you'll use more air as they are the largest muscle in your body. Muscles need oxygen.

If you're nervous or anxious, you'll use more air.

If you're a big person, you'll use more air than someone smaller. Females are usually the best at air consumption because of their smaller mass and smaller musculature. Big guys usually get their butts kicked by females in the breathing department, sometimes by as much as over half a tank in the same dive conditions and same equipment.

Some divers just use less air, all things being equal, even if they smoke, which is also a bit of a demand on air.

Ok, as you can see, there are a lot of things that influence how much air you use on a dive. I'll give you some numbers to think about here.

Myself, a male, 5 foot 10, 170 pounds, a smoker and 44 years old. On a dive to 60 feet in 60 F water with a 7 mm suit, Alum 80 tank,  I'll use my 2/3rds of a tank ( 1/3 is always your reserve) in about  42 minutes (average), providing I'm swimming normally and in no current. I'm actually pretty good on air for what I am. I usually have to cut my dive short because my buddy is the one with an air issue.  

Same conditions, except for depth and that number goes waaay down as the depth increases and waaay up if the depth decreases. You may even find yourself not limited to what air you have in the tank, but rather what your allowable bottom time is depending on any previous dives that day. There are a lot of other variables to consider such as staying within non decompression limits diving. You may simply NOT be allowed to use that entire tank, all depending on what that day's profiles were or even the dive profile you're on now, even if it's the first dive of the day!!!

How much does a tank cost? An alum 80 generally goes for anywhere between 170 -225 bucks including valve and first fill. More if the tank will be used for Nitrox as it will require cleaning.

Also, contrary to what's been posted here. Do NOT get a J valve ( manual reserve) on the tank. Most dive shops won't install one anyway even if you ask. Reason is that they aren't safe. They can be accidentally switched to reserve "on" during a dive, giving you the impression that since you're still able to draw a breath, you have at least 500 psi in the tank. You may be almost empty instead. You should be looking at your pressure gauge every minute or so, to see your air status and not relying on something as dangerous and as outdated as those valves. Those J valves also have a higher failure rate than a K valve and it's doubtful you'd find one as new since I don't believe they are manufactured anymore. The dive shop will be putting on a K valve, rest assured.

There is also a key advantage to owning your own tanks. You're usually ready to dive at a moments notice. There is no going to a local dive shop at the last minute, waiting an hour and then going to the dive site. You and your tanks are going diving, not adding to the stress pre dive. Most regular divers will opt to own two tanks as well. If you only plan on diving once in a blue moon or only in a foreign destination that requires air travel, only then it makes sense to not own and rent instead.

Answer 3

5 days

Answer 4

too many variables here to give you an accurate answer...  depth, salinity, you're physical condition, how you control your BC, how well you keep your cool underwater and if you keep yourself from hyperventilating

Answer 5

It may be best to call a scuba equipment rental outfit and ask them.

I don't dive but I am on 2 lpm of oxygen all the time and I know that an E tank lasts for four hours and is upwards of $45.00 a tank.

Good luck,

Hope

Answer 6

A standard tank even if you hyperventilate while your breathing will at least give you 30 minutes of air. It is more cost effective to use the tanks that they provide on the dives than to buy your own especially if it just for recreational use. Unless you have your own air compressor and dive professionally usually there is not much reason to buy your own tank. I dive and have my own tank, but I have only used my tank just one time. Every other time the places where I was diving preferred to provide the tanks and it was less expensive to use theirs.

Answer 7

One SCUBA!!!! tank lasts the average person one hour, with leisurely swimming ABOVE 30 feet deep. (one atmosphere)

However, below that, nearing 2 atmospheres, 60 feet or so.. the air time is about HALF THAT.

Most of the good stuff to look at is in the upper 30 feet of the ocean, so try to return to the boat in 50 minutes or less.  Allow less time if you are swimming against the current, or swimming fast, or using up energy.

USE A PRESSURE guage on your tank.  Get a tank with a reserve valve. You can feel the air running out, then you pull the lever and have a few minutes more.