Question re: doubles

[doctormike]

Hey, just thought that I would see what people thought about this plan.... always in the market for good advice from experienced divers!

I dive locally (NYC) during the season, and I have two steel 119's which I swap between dives. Recreational diving only, mainly interested in photography and video. I dive dry, with a BP/W.

I do want to eventually start technical training, but for family reasons I have decided to hold off for another season (that is, probably will start the classes a year from now in the winter, and the open water work in the spring/summer of 2013). However, I was considering doubling up the 119's (manifolded, not independent) to (a) get used to the weight and (b) get comfortable with things like valve drills, using the manifold, etc.. It would also be nice not to have to switch tanks between dives, but that's a minor point.

I have tried the double 119's using travel bands, and was able to handle the weight walking to the quarry without much difficulty. I also know an instructor who will work with me this spring to make sure that I am OK with this setup before going into the ocean, and then work with me in the ocean as well in the beginning. Obviously, I'll be watching my bottom time to make sure that I don't inadvertently get into deco before I have that training....

Does this sound like a good idea? Or better to just dive single for another season and then do the tech training and the doubles at the same time? Anything that I haven't thought of?

Thanks!

Mike

 

[gsk3]

How tall are you? You may be happier with smaller doubles (Al80, LP85, or HP100) if you're small like me. Due to not needing to waste the reserve from the first dive, you probably need a lot less gas than you think to do two rec. dives. And a 40 stage weighs basically nothing and is more flexible if you need a little more gas.

 

[cool_hardware52]

Hey, just thought that I would see what people thought about this plan.... always in the market for good advice from experienced divers!

I dive locally (NYC) during the season, and I have two steel 119's which I swap between dives. Recreational diving only, mainly interested in photography and video. I dive dry, with a BP/W.

I do want to eventually start technical training, but for family reasons I have decided to hold off for another season (that is, probably will start the classes a year from now in the winter, and the open water work in the spring/summer of 2013). However, I was considering doubling up the 119's (manifolded, not independent) to (a) get used to the weight and (b) get comfortable with things like valve drills, using the manifold, etc.. It would also be nice not to have to switch tanks between dives, but that's a minor point.

I have tried the double 119's using travel bands, and was able to handle the weight walking to the quarry without much difficulty. I also know an instructor who will work with me this spring to make sure that I am OK with this setup before going into the ocean, and then work with me in the ocean as well in the beginning. Obviously, I'll be watching my bottom time to make sure that I don't inadvertently get into deco before I have that training....

Does this sound like a good idea? Or better to just dive single for another season and then do the tech training and the doubles at the same time? Anything that I haven't thought of?

Thanks!

Mike

If you have a mentor I'd say go for it. Get some real tank bands. Without a mentor be very careful about valve drills etc. You can easily turn off all your gas. Make sure you understand how a manifold works, many are a bit in dark about what is connected to what.

Keep in mind that large volumes of gas can get you into trouble too, keep your NDL's in mind, sounds like you are already aware of these risks.

Doubles are actually easier to dive than singles because the added mass slows every thing down.

Good luck,

Tobin

 

[doctormike]

How tall are you? You may be happier with smaller doubles (Al80, LP85, or HP100) if you're small like me. Due to not needing to waste the reserve from the first dive, you probably need a lot less gas than you think to do two rec. dives. And a 40 stage weighs basically nothing and is more flexible if you need a little more gas.

Thanks for the reply! I'm 6'2"...

I really don't want to cut down my gas supply, the 119's have been good for me so far, so using two of them to do two similar dives makes sense. I dive with a 30 pony now, which I agree I barely notice when I'm diving. However, I would consider that a redundant air source, and would not included it in gas calculations.

Are you saying that you dive with the stage and doubles? Are you using a richer mix in the stage for accelerated deco? Remember, I'm planning on just doing recreational diving for the next year, and if I had redundancy with the doubles, I would probably not be using the pony/stage until I got into the tech training...

 

[doctormike]

If you have a mentor I'd say go for it. Get some real tank bands. Without a mentor be very careful about valve drills etc. You can easily turn off all your gas. Make sure you understand how a manifold works, many are a bit in dark about what is connected to what.

Keep in mind that large volumes of gas can get you into trouble too, keep your NDL's in mind, sounds like you are already aware of these risks.

Doubles are actually easier to dive than singles because the added mass slows every thing down.

Good luck,

Tobin

Thanks! I appreciate the response... yes, I do need to watch the bottom time, don't want to get into deco until I'm ready!

I also need to consider if I can afford to maintain a separate single tank regulator setup for travel, or if I should just economize and switch hoses around when I fly somewhere warm...

 

[Colliam7]

I was considering doubling up the 119's (manifolded, not independent) to (a) get used to the weight and (b) get comfortable with things like valve drills, using the manifold, etc.. . . . Does this sound like a good idea?

It is very reasonable. Yes, it will be good to be sure you have a local resource / mentor to go to with questions, beginning with the set-up itself. And, of course, be mindful of your bottom time so you don't drift into a deco obligation. But, those concerns have already been covered. I think that doubling up the 119s, and getting used to them, is a very reasonable idea. CAVEAT: For me, personally, double 119s are not my favorite doubles rig. They are heavy / bulky to move around on land, they are short / compact in the water so you have a lot of weight in a small space that can 'challenge' your trim skills. However, if that is all I had, I would dive them regularly. Given a choice, I prefer double 100s, or even double 80s. But, I started with double 120s - that is what I had at the time I wanted to begin diving doubles, and I didn't have the money to buy more tanks. They worked, even though I am a bit short for the 120s. So, you can make the 119s work - frankly a lot of people really like them.

I also need to consider if I can afford to maintain a separate single tank regulator setup for travel, or if I should just economize and switch hoses around when I fly somewhere warm

Find a way to 'afford' the single tank reg. Reconfiguring your regs from doubles to singles to doubles is an annoyance. Frankly, I would set up a doubles rig, and then buy another reg on eBay and set it up for single cylinder diving.

 

[mathauck0814]

At 6'2" the 119 shouldn't be too tall. Practice a few valve shutdown drills (you can start on land, sitting in front of your tank and then move to the pool/shallow water - if you're doing this in water, do it with a buddy that's aware of what you're up to until you're comfortable with it). That will help you get comfortable operating the manifold and start to build the muscle memory you'll want to be able to rely on if you need to isolate an issue due to failure.

Bibian Wong : Valve Shutdown Drill - YouTube

There's no reason not to dive a twinset assuming you've got the lift sorted from a BC perspective and make sure you pay attention to NDL so you don't accidentally end up in deco. I don't dive singles anymore except for shore dives with long surface swims - it's nice to have the redundancy and I find that my twinset trims out better.

Get together with your mentor and sort out the weighting/trim/valve drills/etc and then just dive it where you would have otherwise dove your single setup. You'll be a lot more comfortable when you do finally start with tech.

 

[pheel]

Does this sound like a good idea? Or better to just dive single for another season and then do the tech training and the doubles at the same time? Anything that I haven't thought of?

Thanks!

Mike

Good idea. This is exactly what I did last spring. Eventually I'll go tech but for now I stay within NDL. IMO, there is nothing wrong with doubles and recreational diving.

 

[DevonDiver]

i teach 'intro to doubles' and have even offered classes in doubles to recreational divers. I don't see doubles as the preserve of tech divers.

there's nothing technical about them - just a tool for a job. the tool doesn't dictate the task..it's vice-versa.

If you dive bp&w then you're halfway there. just get some help training proper shutdown drills and responses. fitting, weighting, trim and buoyancy should already be understood.

 

[Doc Harry]

What Tobin said.

You might spend your first few dives struggling to keep your trim flat and your head up. Just keep at it, keep your head up, and keep practicing, learning to trim out heavy steel cylinders is like learning to ride bicycle.
Try...crash!
Try...crash!
Try...crash!
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Try...crash!
Try...crash!
Try...Hey! I got it!