Deco Bottles- 30cf vs 40cf?

[ColdWaterHusky]

40 are the standard, but 30s seem to be common as well. I'm just starting my venture into tec diving and am setting up my first deco bottle. I'd like to go with a 40, but no dive shop in my area has any in stock. Is it worth it to order one in, or go with the 30s avalible around here? What's your view on 30s vs 40s? When is one prefferable to the other?

 

[Aquabot]

40 are the standard, but 30s seem to be common as well. I'm just starting my venture into tec diving and am setting up my first deco bottle. I'd like to go with a 40, but no dive shop in my area has any in stock. Is it worth it to order one in, or go with the 30s avalible around here? What's your view on 30s vs 40s? When is one prefferable to the other?

I bought one from Addhelium.com. Great people and I couldn't have been happier with the cylinder(40cf).

Sent from my DROID RAZR HD using Tapatalk 2

 

[PfcAJ]

They're quite similar in size and buoyancy, but the 40 packs more gas. Worth having, imo, esp if you can't get boosted o2.

My guess is that there's a good reason why the 40s are out of stock

 

[James R]

I'd get the AL40 between those two...or even better a Lp45 or Lp50 steel cylinder.

 

[Tom Winters]

Everyone will tell you to get 40cf bottles. I have 40cf bottles.

BUT<-----get what you're gonna need. 30's are easier to lug. I have not used my 40's for years - doing the long deco dives is a PITA with logistics. I don't know what kind of diving you are going to do - for all I know, you're one of those Michigan Maniacs who wants to ride the Falls at Niagara and then swim underwater to Detroit.

I keep meaning to dive with a bailout bottle. I was going to convert a 40, but I like those leetle 30's a lot more. And, depending on what you do, you might need 80's.

Tough call. Good luck.

 

[elan]

Even with 40 you have to have a decent. sac rate to do 20+ min deco. Beside your gas you also carry the reserve for the team. So 30 could be even worse. Personally I would skip 30 and just use 80 for deco gas if you have hard time finding 40

 

[Scott]

Doesn't matter, if you end up getting into tech you're going to end up with a number of different sized deco cylinders eventually.

 

[GrimSleeper]

Even with 40 you have to have a decent. sac rate to do 20+ min deco. Beside your gas you also carry the reserve for the team. So 30 could be even worse. Personally I would skip 30 and just use 80 for deco gas if you have hard time finding 40

+1 for 80 rather than 30.

40s are good, but there are advantages to getting used to slung 80s - no need to boost O2 unless you're doing a monster of a dive, more dives on a single fill if you're using EAN50, plus once you get used to diving with one or two (or occasionally three if you're doing something really stupid... ) 80s as sling tanks, any time you do a dive with 40s it'll feel like the easiest thing in the world.

 

[TSandM]

It really depends on the dives you are going to do.

For a typical GUE Tech 1 dive, you're looking at 20 to 30 minutes at 150, with up to a 30 minute deco obligation. If you run the math for the gas requirements for 30 minutes of deco, with reserves for lost deco gas, you're barely going to make it on a 40. A 30 would only be useful for the "light technical" dives where your deco obligation is kept fairly short.

I do like 40's, though, because they totally disappear when you carry them. I'm always aware of an 80 when I have to lug one around.

 

[j2s]

Doesn't matter, if you end up getting into tech you're going to end up with a number of different sized deco cylinders eventually.

This and what James R, said....The AL40's can be a bit of a pain due to the bottom floating up..........I like the LP steel 45's and 50's for easier handling.....But it depends on what you'll be doing and preference........Be patient and go to Cave Divers Forum, for used 40's.......