Tank size for new divers

[Dive4Life]

I have the LP 120 @ 2640. It is a monstrosity of a tank but I bought it for deep deco dives. Probably should have gone doubles but that one tank can do the job really well when over filled. Just hope it doesn't pop.

 

[LUBOLD8431]

Take this as advice, not as a slam, but as a new diver, you dont need a cylinder that holds 149 cu ft of gas. Rethink your choice of cylinder. Your logic is sound, but the choice of cylinder is wrong. That sam logic will work with a E7-100, which is much lighter, more manageable, and more along the lines of what you need for the types of dives you will be doing in the immediate future. Dont get ahead of yourself.

 

[bg10459]

Take this as advice, not as a slam, but as a new diver, you dont need a cylinder that holds 149 cu ft of gas.

Did I forget to mention that I am 6'-6", 250 lbs. I've seen an LP 120 and they don't seem too big or heavy compared to an AL 80. I know they are, but at only a few inches longer and 3/4" wider, the size isn't a problem. The added weight helps move weight off my belt too. I currently dive with an AL 80 and want/need more air for longer, deeper dives. I don't want to buy many tanks and plan to dive singles only. It seems like a great choice for someone my size for longer dives. For the short dives I'll stick with an AL 80. Thanks for the input.

 

[jonnythan]

I currently dive with an AL 80 and want/need more air for longer, deeper dives.

I think Lubold was trying to say that as a newbie, being limited by the gas in an 80 or 10 cf tank adds a large margin of safety - it can be difficult to go past the NDL's except on the third or fourth dive of the day. Having 149 cf and doing deeper dives essentially gives you enough rope to hang yourself, if you get my drift. 149 cf is way too much for virtually any NDL dive - 100 or 119 should be more than adequate.

I've been working on my breathing patterns and can now push the NDL for just about any dive on an Al 80 alone. By mu quick calculation, 149 cf will allow even the heaviest breather to spend over 35 minutes at 100 feet, and an average breather 50 minutes at that depth.

 

[ScubaDadMiami]

I have a set of double E-7 120s. I like them because I can fill them with low pressure and still use them like double 95s. On the other hand, when the mission requires it, I will take them up to 3442.

You may think that it is hydrodynamically insignificant to compare the 7.3 inch versus the 8 inch tank. However, I swear that I can feel a difference in how much easier these swim through the water. I guess it has to do with the geometric increase in resistance for even a slight change in dimension.

One thing about these tanks: they do have a funky balance. They tend to be top heavy. Once you get that issue resolved, I think that they are good, all around tanks.

 

[Scuba_Vixen]

Take this as advice, not as a slam, but as a new diver, you dont need a cylinder that holds 149 cu ft of gas.

Did I forget to mention that I am 6'-6", 250 lbs. I've seen an LP 120 and they don't seem too big or heavy compared to an AL 80. I know they are, but at only a few inches longer and 3/4" wider, the size isn't a problem. The added weight helps move weight off my belt too. I currently dive with an AL 80 and want/need more air for longer, deeper dives. I don't want to buy many tanks and plan to dive singles only. It seems like a great choice for someone my size for longer dives. For the short dives I'll stick with an AL 80. Thanks for the input.

I'm with the moose on this one, 100%.
You have to work hard to get past the new diver "bigger is better" syndrone .... 6'6" or 5'6", .. it doesn't matter. Untill you have the skills and experience to where you run out of NDL before you run low on air with an 80, (maybe a 100 if it's cold or currents) ... opting for the band aid approach (bigger tanks) to longer bottom times is counterproductive at best. You mention deeper longer dives, once you have the skills and experience you need for those dives, you won't likely need a big tank anyway. After all, "longer" stops at the end of the NDL. The comment; "Having 149 cf and doing deeper dives essentially gives you enough rope to hang yourself" is dead on.

The only logical use for a single lp120 is to get 2 dives from 1 fill ...handy if you're beach diving and don't want to leave a tank in the truck while you dive the other, or alternatively if you pay the same for a nitrox fill, whether it's an 80 or an overfill to 3000 on a 120. That's like 2 dives for the price of 1 and can be a big savings if you dive a lot and a trox fill costs $10 or $15 or so. (also nice not to have to switch tanks on a rocking boat)

Take some time to get in a few dozen dives before you race off to get that monster of a tank. You won't be the first to thank me for telling you so.

dive every chance you get,

Darlene

 

[Scuba_Vixen]

"I've met some really big divers who use a LOT of air, newbies mostly but I'm not sure that experience changes air consumption much. It happens but I wouldn't make any assumptions."

No assumption about it, .. If you dive regularly, learn good breathing techniques and always practice them as consciously as you can .... Your sac rate will improve remarkably from what it was as a newbie. Better (more efficient) breathing is a skill to be developed just as bouyancy control is. Not surprisingly, they are interrelated. Skills improvement is proportional to proper efforts made in that endeavor.

While the "Dive Today" advertising has brought a lot of new folks into diving, It's imparted too much of a "Got certified today, Let's do the Doria tomorrow" mindset in a lot of new, young, male, divers.

If the agencies really told prospective students how really "entry level" the OW cert is .... while it would make for better divers, it would Not make for good profit levels ... So don't look for any changes.

Hopefully, the newguys will heed the advice of those who've been there and done that already.

Darlene

 

[pdoege]

2 big LP120s. At the time I had a really bad SAC and I used the big tanks to compensate.

The other posters are very correct about having enough air to hang yourself with. A LP120/E8-149 will let you go right through the NDL, no problem.

Now I use little HP80s for recreational dives. Much more comfy. My buddies are typically using HP100s.

I don't even use the 120s for technical or caves dives. They are really large. I use double 104s.

So, in my experience, the 120s were a waste of money. I should have gotten HP80s or 100s and waited for my SAC to improve.

Peter

 

[pescador775]

Well, some people have lungs the size of coffee cans but the guy asking this question probably has twin gallon jugs. Given this, decreasing the air consumption rate is problematical. Size, weight and muscle mass make it so. Other than metabolism, air consumption is partly a head game. Free diving builds endurance and self control and is a more rigorous training method than any kind of indoctrination in a class setting. Some unusually nervous people seem to improve with SCUBA experience, especially if they have moderate height and weight. One way to test this is to start them with a double hose regulator then move on to the single hose when they stop complaining of air 'starvation'.

No assumption about it, .. If you dive regularly, learn good breathing techniques and always practice them as consciously as you can .... Your sac rate will improve remarkably from what it was as a newbie. Better (more efficient) breathing is a skill to be developed just as bouyancy control is. Not surprisingly, they are interrelated. Skills improvement is proportional to proper efforts made in that endeavor.

 

[jgarysmith]

l"LISTEN TO THE VIXEN" SHE KNOWS WHAT SHE IS TALKING ABOUT. SHE SET ME STRAIHT ON MY TANK CHOICE WHEN I WAS NEWER AND WANTED A BIG TANK.