TexasMike
Contributor
Which diving course teaches you how to use doubles safely? I'm in no rush to get there, but was curious.
When to Double?
- Thread starter TexasMike
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
blacknet
Contributor
Hello,
Well I do know you will get into things like that in the advanced nitrox class thru IANTD (among other agencies but I know iantd better so i'll use them here) like the deep, technical nitrox and trimix classes. I have heard of people who was so horrible on gas managment they had to switch to doubles to get an adequate gas supply while at depth. Tho doubles are, typicaly, for longer bottom time, whether be shallow or deeper depths. It only makes sence the deeper you go the more gas you must bring with you so in deep diving you will need doubles. (but that's not the topic here is it?)
Well according to the IANTD standards it's more based upon DOUBLE regulators where one can be shut down in case of emergency's than double tanks.
I suppose to properly use doubles you must first learn what your (and your buddy's) gas consumption rate (SAC) is, understand how deep and how long you will be diving, THEN allow for adequate gas (SAC ratio)durring the dive.
Ed
Well I do know you will get into things like that in the advanced nitrox class thru IANTD (among other agencies but I know iantd better so i'll use them here) like the deep, technical nitrox and trimix classes. I have heard of people who was so horrible on gas managment they had to switch to doubles to get an adequate gas supply while at depth. Tho doubles are, typicaly, for longer bottom time, whether be shallow or deeper depths. It only makes sence the deeper you go the more gas you must bring with you so in deep diving you will need doubles. (but that's not the topic here is it?)
Well according to the IANTD standards it's more based upon DOUBLE regulators where one can be shut down in case of emergency's than double tanks.
I suppose to properly use doubles you must first learn what your (and your buddy's) gas consumption rate (SAC) is, understand how deep and how long you will be diving, THEN allow for adequate gas (SAC ratio)durring the dive.
Ed
Using doubles isn't all that much different from using a single. The main differences are buoyancy, weight and stability.
Buoyancy will change depending on your choice of tanks, but it will change.
Two tanks are heavier and therefore more difficult to carry out of the water. Choose tanks you'll be able to handle. There's a big difference between twin 50's & twin 131's.
Swimming with doubles is actually easier than with a single tank. For extreme ease, use triples. There is no tendancy to flip on to your back if you roll slightly to one side. With a heavy single tank, you'll often get pulled over unless you're used to the effect and compensate.
I use doubles most of the time for all types of diving. Typically on two tank dives, I merely burn half my air on the first dive & the other half on the second.
A common misconception is that you can only use doubles with a backplate and a wing. That is merely one option. You can use doubles with any BC that will accomodate a single. Actually, the use of doubles (and triples) predates the invention of the BC.
WWW
Buoyancy will change depending on your choice of tanks, but it will change.
Two tanks are heavier and therefore more difficult to carry out of the water. Choose tanks you'll be able to handle. There's a big difference between twin 50's & twin 131's.
Swimming with doubles is actually easier than with a single tank. For extreme ease, use triples. There is no tendancy to flip on to your back if you roll slightly to one side. With a heavy single tank, you'll often get pulled over unless you're used to the effect and compensate.
I use doubles most of the time for all types of diving. Typically on two tank dives, I merely burn half my air on the first dive & the other half on the second.
A common misconception is that you can only use doubles with a backplate and a wing. That is merely one option. You can use doubles with any BC that will accomodate a single. Actually, the use of doubles (and triples) predates the invention of the BC.
WWW
OP
TexasMike
Contributor
Thanks for the info so far, but not quite what I was looking for.
Which class teaches you safe use of doubles? As in Rescue teaches you about the different diving emergencies and how to handle them.
Which class teaches you safe use of doubles? As in Rescue teaches you about the different diving emergencies and how to handle them.
There's not enough material for a class, kinda like night diving.
WWW
WWW
blacknet
Contributor
Hello,
How about this -> http://www.iantd.com/tom/
Advanced Deep Air Technical EANx Technical Deep Air"
Minimum Gas supply of double 100 cubic foot tanks
Cave or EANx Cave or Wreck or EANx Wreck:
Minimum gas supply double 100 cubic foot tanks
This what your looking for?
Ed
How about this -> http://www.iantd.com/tom/
Advanced Deep Air Technical EANx Technical Deep Air"
Minimum Gas supply of double 100 cubic foot tanks
Cave or EANx Cave or Wreck or EANx Wreck:
Minimum gas supply double 100 cubic foot tanks
This what your looking for?
Ed
As far as I know, there is no specific class on the use of doubles. I asked the same question myself when I was up in Seattle of my favorite dive shop owner. She said if I wanted to go doubles, she would gladly show me how to use them, but it wasn't an actual class or certification, and she said they weren't difficult to learn.
The Chairman
Chairman of the Board
Hey Texas Mike,
There are no tricks to using doubles. Just as with any gear configuration change, your first stop should be a pool to try it out. I think my first sortie with doubles was also my first time out with my OMS BC. I even went with different regulators as my Micra was not set up for DIN then. Too much change at one time and it was a bit disorienting. I did have to re-learn how to balance, and I went over the three different valves and what controlled at the dive shop. Oh yeah, I developed some strong leg muscles too!!!
BTW, I had to make a similar readjustment when I went to single Pressed Steel HP120's. They are a tad more awkward than my twin LP72's.
There are no tricks to using doubles. Just as with any gear configuration change, your first stop should be a pool to try it out. I think my first sortie with doubles was also my first time out with my OMS BC. I even went with different regulators as my Micra was not set up for DIN then. Too much change at one time and it was a bit disorienting. I did have to re-learn how to balance, and I went over the three different valves and what controlled at the dive shop. Oh yeah, I developed some strong leg muscles too!!!
BTW, I had to make a similar readjustment when I went to single Pressed Steel HP120's. They are a tad more awkward than my twin LP72's.
blacknet
Contributor
Hello,
the 12L tank is about an 80 cubic ft. I don't have the exact formula for conversion but here's a useful conversion page (it's also their tanks) (PLEASE NOTE! I am *NOT* using this as advertisment) http://www.omsdive.com/cyl_spec.html
Ed
the 12L tank is about an 80 cubic ft. I don't have the exact formula for conversion but here's a useful conversion page (it's also their tanks) (PLEASE NOTE! I am *NOT* using this as advertisment) http://www.omsdive.com/cyl_spec.html
Ed
Similar threads
