100cf tanks

[Greg Doyle]

Steel tanks? Yes! I love mine.

However, if you're chewing through your air, might I suggest a few things.

• Get your attitude right
  • You should be flat, flat, flat!
  • Often referred to as 'trim'.
• Hold your hands together in front of you.
  • Flailing (sculling) wastes energy
  • Sculling ruins trim
  • Sculling scares fish
  • Holding your hands in front of you, actually helps with trim
• SLOW DOWN!
  • It's a big ocean and you're not going to see it all in one dive
    • Why even try?
  • Going slow will allow you to stay down a lot longer!
  • The slower you go, the more you will see.
  • Make your buddy/DM stay back with you, not you up with them!
• Use down lines correctly
  • Pull your self down: DON'T KICK!
  • Pace yourself. Did I mention going slow?
  • If you seem to be panting when you hit the deck, you're doing it wrong.
• Stay out of the current!
  • Usually the closer to the bottom, the better off your are.
  • Hide behind structure whenever possible.
  • Use the rules of Dodge ball...
    • Dodge
    • Dive
    • Dip
    • Duck and...
    • Dodge

All great points, Thanks.
I took my buoyancy class a few weeks ago as part of my PADI AOW and those points were made clear. It's the practice though isn't it......

Regarding the difference using 100's vs. 80s, I did six dives this weekend down in the Keys with Key Dives in Islamorada. My first two dives on Saturday were on the AL100's and I was able to stay down about 10 mins longer than I have ever before at depths between 65-45 feet. My first two dives on Sunday, the same. It felt great to not be the 1st guy to head up!
The last two dives on Sunday afternoon, I went back to AL80s and needed to add 2lbs more weight to get negatively buoyant. However, my dive time, for me, was about the same as on the 100's at 40'-30'. Just a few minutes longer. This was with a strong current and really cloudy water. So, yeh, I'm starting to get there.

I definitely am getting more relaxed and pacing my breathing, counting to 5 in, counting to 7 out, but sometimes I just feel like I need to really exhale and inhale deep. About every 3 or four cycles of pacing my breathing.

It's frustrating to see a kid on the dive that's crazily waving his arms around, flailing his legs all over the place and blowing a constant stream of bubbles end his dive with 500PSI more than me. Getting old sucks but it beats the alternative.

Thanks everyone for the input.
G

 

[Tbar]

pacing my breathing, counting to 5 in, counting to 7 out, but sometimes I just feel like I need to really exhale and inhale deep. About every 3 or four cycles of pacing my breathing.

When you stop focusing on your breathing and enjoy the environment your time will improve. Don't worry about being the first to finish, ensure you have the best time while under the water.

 

[decompression]

Thanks for the replies folks. I'll find out tomorrow if the tank is Al or steel.
It's a wreck dive to just over 100' and the last time I did that, I went through air way too quickly. I'm also going to take the Eanx test on Sunday.

This is a business trip in FL and starting next week I'll be back home and jumping in Puget Sound for Dry Suit training with my LDS. I'll do the class with 80s.
I'm still a ways out from purchasing tanks.
Decompression, are you in the Seattle area? I see the 206 area code.

In the mean time, as little diving as I've had with the dry suit so far, it's a completely different ways of diving from here in FL. I'd be open to a GUE class while here in FL. Perhaps the next trip down.
Thanks,
I'll look into it.

Hey Greg, I'm just up North of you in Victoria BC, I'm in Seattle occasionally.

 

[2airishuman]

I use larger cylinders for most dives.

It is my experience that most dive operators that offer 100 cf cylinders use AL100s. These typically have similar buoyancy properties when empty to empty AL80s, when full they will be slightly more negative. They are 8" cylinders and on most dive boats they will not fit the racks which is a minor nuisance. These are 3300 PSI cylinders and most operators will short fill them so you'll end up with closer to 90 cf instead of the 77 cf you'd get with an AL80.

A few operators use steel HP100s. Take 4 pounds of lead off your belt for these.

I got a good deal on four used HP120s when I started diving and have come to love them. My air consumption has improved somewhat since then but I'm still a big guy. If you use more air than most people then consider what you can comfortably lift and what will fit your height. If your build allows you to carry 120s comfortably I cannot imagine why you wouldn't want them. They are a 7.25" cylinder and will fit standard racks. Nobody ever had a dive go badly because they brought too much air.

 

[halocline]

Nobody ever had a dive go badly because they brought too much air.

I understand your sentiment but technically this is not true. Extra gas can certainly mean extra exposure to DCS risk, if having the extra gas alters your dive behavior. I'm sure is does that for some divers, not you of course!

In general though, it does make some sense for big folks to use big tanks. I just think for the OP, with 10 dives to his credit, it's probably not worth worrying about yet.

 

[Greg Doyle]

I use larger cylinders for most dives.

It is my experience that most dive operators that offer 100 cf cylinders use AL100s. These typically have similar buoyancy properties when empty to empty AL80s, when full they will be slightly more negative. They are 8" cylinders and on most dive boats they will not fit the racks which is a minor nuisance. These are 3300 PSI cylinders and most operators will short fill them so you'll end up with closer to 90 cf instead of the 77 cf you'd get with an AL80.

A few operators use steel HP100s. Take 4 pounds of lead off your belt for these.

I got a good deal on four used HP120s when I started diving and have come to love them. My air consumption has improved somewhat since then but I'm still a big guy. If you use more air than most people then consider what you can comfortably lift and what will fit your height. If your build allows you to carry 120s comfortably I cannot imagine why you wouldn't want them. They are a 7.25" cylinder and will fit standard racks. Nobody ever had a dive go badly because they brought too much air.

It's true, the tanks don't fit the racks and the tanks and BCD end up laying on the floor between the camera and goggle buckets.
If you know the Captain on the boat down there, he's a fairly big guy who comes off rough and has a sense of humor that could put you sideways until you get to know him. His comment "Who the heck brought those 55 gallon drums on board?"
I take his humor with a grain of salt as his choice of music as we boarded the boat was Katy Perry........
The shop didn't short fill them, they were right at 3200.
As I mentioned earlier, I took two lbs off on the AL100's and put it back on with the 80s.
G

 

[Greg Doyle]

I understand your sentiment but technically this is not true. Extra gas can certainly mean extra exposure to DCS risk, if having the extra gas alters your dive behavior. I'm sure is does that for some divers, not you of course!

In general though, it does make some sense for big folks to use big tanks. I just think for the OP, with 10 dives to his credit, it's probably not worth worrying about yet.

My original post was really about weight differences and byouancy. I didn't figure I'd have and issue with too much bottom time, but that's a good point, if not paying attention and doing consecutive dives, one might get themselves in trouble.
I also got EANX certified last week, so that will help too.
G

 

[DavidFL]

Hi Greg, welcome. +1 for the HP Steel 100s for the kind of diving I do here in Florida. I have two AL80s that are now 27 years old; those have been my "throw in the truck" tanks for "local" dives to West Palm Beach and the Keys, but last year I bought two of these newer HP Steel 100s and I'm completely satisfied with them. As you have begun to discover, there are a lot of factors. The Nitrox capability (which I dive basically all the time) will extend the potential for more bottom time, but in many cases the other things like your buddy, or the boat's 'policy', or getting chilled will set the time when you start up. If you can focus on it, try to avoid that "first guy to head up" judgment. Easier said than done, I've been diving for 50 years and I still regularly see and register the competitive impulses, but you'll have another breakthrough in many ways if you get the "aha" experience that it actually isn't a competition; it isn't a race; sometimes just staying in the same place for ten minutes and see how the view and the experience changes will make the best dive of a trip. I have a great dive buddy; when either of us calls the dive for any reason at any time it goes in the log as another 'out of this world' experience that was unique to us.

 

[2airishuman]

I understand your sentiment but technically this is not true. Extra gas can certainly mean extra exposure to DCS risk, if having the extra gas alters your dive behavior. I'm sure is does that for some divers, not you of course!

In general though, it does make some sense for big folks to use big tanks. I just think for the OP, with 10 dives to his credit, it's probably not worth worrying about yet.

Thread hijack coming, sorry. (I think the OP got what he wanted out of this thread, or I wouldn't)

The received wisdom is that the standard capacity of the once-universal LP72 dive cylinder was determined by the dive industry because it would not provide sufficient air for casual divers to encounter truly serious problems with DCS. The AL80 was essentially a cost-reduced LP72 with an 8% bump in capacity (71.2 -> 77.0) that didn't change that. There have always been slightly smaller cylinders that have mainly been marketed to women for their easier handling. Currently that's the AL63.

No one disputes the wisdom of having someone who is, say, 5'6" and 140 pounds use an AL63. They're going to use less air. The cylinder will be easier to handle.

The flip side of it is that a diver who is, say, 6'3" and 230 pounds is better off with something larger than an AL80, and will be better able to get dives of reasonable duration, and will better match air consumption with whoever else is diving. But Scubaboard and the industry are telling guys like this to relax and work on their skills. The thing is that, while this will help, someone who is big and muscular is never going to match the air consumption rates of other divers who are equally skilled and experienced. Lean muscle mass increases basal metabolism and so big guys who go to the gym are going to breathe more air and burn more oxygen just sitting there.

Larger cylinders are a hassle for dive ops so they don't promote them. I wish they would. I have 25% more muscle mass than most other divers. 25% more gas is enough for me to be at parity with them for air utilization. It makes me happier. It makes whoever I'm diving with happier. It removes a source of stress and makes for a safer dive.

If it's a nitrox dive and everyone is using steel 100s I'll want steel 120s. I'm watching for a good deal on a 149, but for now I have twin 72s and twin 100s I can use for really long dives.

 

[kelemvor]

Thread hijack coming, sorry. (I think the OP got what he wanted out of this thread, or I wouldn't)

The received wisdom is that the standard capacity of the once-universal LP72 dive cylinder was determined by the dive industry because it would not provide sufficient air for casual divers to encounter truly serious problems with DCS. The AL80 was essentially a cost-reduced LP72 with an 8% bump in capacity (71.2 -> 77.0) that didn't change that. There have always been slightly smaller cylinders that have mainly been marketed to women for their easier handling. Currently that's the AL63.

No one disputes the wisdom of having someone who is, say, 5'6" and 140 pounds use an AL63. They're going to use less air. The cylinder will be easier to handle.

The flip side of it is that a diver who is, say, 6'3" and 230 pounds is better off with something larger than an AL80, and will be better able to get dives of reasonable duration, and will better match air consumption with whoever else is diving. But Scubaboard and the industry are telling guys like this to relax and work on their skills. The thing is that, while this will help, someone who is big and muscular is never going to match the air consumption rates of other divers who are equally skilled and experienced. Lean muscle mass increases basal metabolism and so big guys who go to the gym are going to breathe more air and burn more oxygen just sitting there.

Larger cylinders are a hassle for dive ops so they don't promote them. I wish they would. I have 25% more muscle mass than most other divers. 25% more gas is enough for me to be at parity with them for air utilization. It makes me happier. It makes whoever I'm diving with happier. It removes a source of stress and makes for a safer dive.

If it's a nitrox dive and everyone is using steel 100s I'll want steel 120s. I'm watching for a good deal on a 149, but for now I have twin 72s and twin 100s I can use for really long dives.

hear hear