Training for Doubles?

[Riger]

Hello all,

I am AOW with 50 dives.

My wife and I are planning another Liveaboard in the Red Sea in April :D, the problem is that in terms of size we are significantly different (me bigger and taller). Even with me using a 15L tank I need a bit more air in order to extend the dive.

I know that my consumption rate will get better in time, but so does hers and trust me, she is small and she is "very" efficient on her air.

So the question is this: If the LDS provides the twin set and have a suitable BCD, do I require any training to use the twins other than the tech brief on the actual valve system?

Thanks in advance.

Richard

[tgsmith]

It'd be wise to practice beforehand with some local divers that are experienced with doubles, or to take an intro-to-tech class. It's really just to know what you're doing/how to set them up. Usually the first few dives for new doubles-users can be quite amusing. If you're spending the money on a live-aboard it'd make sense to spend the money to make it worthwhile, ya know?

Have fun!

[battles2a5]

You might be treating the symptom and not the problem. AOW w/ 50 dives is still pretty new. Working with a good mentor or instructor on bouyancy + technique, or doing some cardio will drop your consumption considerably. If you just want more gas, doubles aren't the answer. There are all sorts of new complications that far outweight the benefit of just the additional gas. With the suggestions above, you will likely be on par with the other folks on the liveaboard. And if you do decide to move into technical diving where doubles are appropriate, the skills will carry over.

At the end of the day, it's obviously your call. If you do decide to move to doubles, do the intro to tech class or work w/ an experienced mentor to help you with the transition.

[Rainer]

I think Ryan pretty much hit this one on the head.

As a new diver, there are lots of things to consider in helping your consumption rate other than adding heavy gear that will take more effort to move through the water.

Working on trim/buoyancy, streamlining your gear, getting more comfortable in the water, and hitting the gym would all be better ways to address your current issue than strapping on a set of doubles.

[halocline]

Just get your wife a smaller tank. :D

It is good advice to do whatever you can to improve your air consumption, but if your wife is quite a bit smaller and also improving as a diver, it's likely she'll always use less gas than you. So what, as long as you can do a "normal" recreational dive, it doesn't matter if she comes up with 1/2 a tank.

Buoyancy control and calm, efficient movement while diving are probably the most important things you can work on to improve your air, and there's always room for improvement in those two areas.

[DoubleHoseDiver]

....and enjoy your dive. Tim

[TSandM]

This will start a firestorm, but what my husband and I do is share gas for a little while, early in the dive. He is a bigger person than I am, and will always use more gas, so we just swim along for a while with both of us on my gas supply, and that evens things out.

NOTE: We do this EARLY in the dive, so no one is low on air; we use a long hose setup, so it's easy and convenient to swim while sharing gas. This is also pretty good practice for air-sharing in general.

I do agree with battles2a5, that it's well worth some work on buoyancy and trim and propulsion, to see if you can bring your consumption down.

Doubles aren't hard to dive, as long as you have a set that will trim out for you, but it often takes some time to get your balance sorted out in them, and I certainly wouldn't want to spend some dives of an expensive vacation off kilter because I was trying to learn new gear.

[jeckyll]

I think that going for doubles at 50 dives is a bit early. I also think TSandM's suggestion is a good one but it relies on some basic skills and being comfortable in the water, as well as understanding how to calculate minimum gas for relevant depth (search for Lamont's post on calculating Rockbottom).

The other option is to offset the tank sizes used one you understand just how much more gas you are using vs your wife. I.E. perhaps you need a 100 cf for her 80 cf.

Most importantly, get more comfortable in the water, don't make sure you're streamlined when swimming, that your trim is good, that you're not fighting with your gear, that you stay relaxed, dive slowly etc. All of which will help make you more efficient and will reduce your gas consumption.

I think between dive 20 and dive 100 my gas use decreased by about 25% :)

[Riger]

All the advice above is understood and appreciated.

Truth of the matter is that I could do with a little cardio work anyway. This will give me a little more motivation.

Thanks all

[Riger]

OK, I am back with more questions related to this.

In the long run, I can work on the issues that will improve my SAC Rates, the problem will always be the my darling wife will always use much less air than me.

So I had a chat with a Techie type this morning and we went through all the different scenario's. Setting aside all the things I can do to improve my SAC Rate, we discussed steel tanks and aluminium tanks and their (significant) difference in buoyancy particularly toward the end of the dive and so forth.

It seems that having a Pony Tank (5 or 7 litre Steel) and either slinging it or strapping it to the main tank, might be the way to go (if I choose to follow this path).

I will have the opportunity to test this configuration prior to the liveaboard, but I was hoping to get feedback from this group first.

Your thought and comments (as always) appreciated.

Regards

Richard

[Riger]

Deleted due to duplicate posting.

[Jorgy]

Additional cylinders (either in the form of a pony or doubles) is certainly a way to increase the amount of gas you carry..........

They do come with additional dive task loading, trim issues, more complex hose routing, more complex donning of gear topside, etc..........none of these items are overly complex and could not be overcome with some practice, and learning to deal with it...........

Before adding an addition cylinder, I might suggest that you investigate your option of cylinders themselves...........

A 10 liter at 230 Bar is roughly the same as an US standard AL 80.......

A 12 liter at 200 Bar is approximately 85 cubic feet........

15 liters is fairly large tank and at 200 Bar it is approximately 106 cubic feet, the same size cylinder at 230 Bar or 300 bar (assuming the tank in rated for it) would be 122 and 159 cubic feet..........

A 18 liter tank is huge and as not as common, at 200 Bar is 127 cubic feet, at 230 bar you end up with 146 cubic feet of gas. The same as many small sets of doubles.........

To use these higher pressure tanks you would need a 300 bar DIN first stage, very common in Europe........

Call the dive op and see what tanks are available, it might be the easiest way to go...........

Perhaps you with a 230 bar 15 liter tank and your wife with a 10 or 12 liter tank might balance out the dive time.........as mentioned before, it is no big deal if she gets out of the water with half a tank left as long as you both enjoyed the dive..........

Hope this helps..........M

[b1gcountry]

I would highly recommend AGAINST the use of a pony as a way of extending out a dive. It is a bad practice to rely on the gas in a pony bottle for a number of reasons:

1. It necessitates you breathing off your pony bottle as a regular part of a dive. You only have one reg on the pony, so you can't share air on it. You perhaps can't donate the reg in your mouth if you are breathing off the pony.

2. Pony bottles are generally reserved for emergencies. You are giving yourself no extra margin when using it in your gas plan.

3. The regulator can be bumped off, and freeflow its gas. perhaps without you knowing immediately. It would suck to rely on a pony bottle, and have it be drained out on you because it was behind you, and freeflowed to nothing

4. You are now introducing a second gas supply. It takes a lot more care to manage two gas supplies vs. just the one. You can also mess yourself up a number of ways by not keeping track of your pressures properly, getting your turn pressure messed up, and running out of air on the way back to the line, or a number of different ways.

5. You now have a third regulator you need to stow somewhere, and that can be a challenge to a new diver.

Diving a pony like this is usually referred to as diving a stage. You can get training for this, but many tech agencies reserve this skill for their highest level of tech classes.

Tom

[Peter Guy]

Riger -- there are short term, and long term, issues you should be considering. Regarding the upcoming trip to the Red Sea -- focus on the short term issue which is:

How can you get more Bottom Time given your current state of experience?

The only reasonable answer, I think, is for you to dive with a bigger tank than your wife. If you start with more gas, you'll have more to use -- period, end of story. IF your Red Sea operator provides the option of a bigger tank, claim it and use it.

My guess is that you'll get more "bang for the buck" by working on being properly (minimally) weighted, getting the weight in the correct places (to "trim" you out best) and swimming slowly using only your feet (NO HANDS!) -- and working on these three things between now and when you leave for the Red Sea. IF you aren't "working hard" (that is, do NOT try to swim fast -- kick, glide, glide, glide -- kick, glide, glide, glide) then the improved cardio may not mean that much. If you can't kick and glide without sinking, you need to work on getting yourself properly weighted AND having the weight in the proper place(s). IF you can kick and then glide, you'll find your consumption will drop substantially and that, along with the larger tank, will get you the Bottom Time you deserve.

BTW, NEVER try to match consumption rates with your wife -- it just doesn't work. To the contrary, think of her as your "underwater refill station" and "borrow a cup of air" whenever you want!

[halocline]

This will start a firestorm, but what my husband and I do is share gas for a little while, early in the dive. He is a bigger person than I am, and will always use more gas, so we just swim along for a while with both of us on my gas supply, and that evens things out.

NOTE: We do this EARLY in the dive, so no one is low on air; we use a long hose setup, so it's easy and convenient to swim while sharing gas. This is also pretty good practice for air-sharing in general.


The only reason this would set off a firestorm is because cyber space is filled with people who love to criticize something that might not fit exactly their attitude.

Your idea is basically the diving equivalent of starting the dive off with different size tanks for different size people, and the result is that both divers reach the turn-around pressure at about the same time. I have a hunch that this is a safer overall scenario than one diver reaching it first, because that diver may be tempted to prolong the dive for the other diver's sake, or for ego's sake. Plus, you get to practice air sharing on each dive, which is added benefit.

[b1gcountry]

This will start a firestorm, but what my husband and I do is share gas for a little while, early in the dive. He is a bigger person than I am, and will always use more gas, so we just swim along for a while with both of us on my gas supply, and that evens things out.

Oh my god you're gonna die! I suppose it might mess with thirds, but I can't imagine those sort of dives requiring thirds.

Tom

PS Kathy is still sour that I have better consumption at roughly twice her weight, so it's not all about size...

(that's what she said!)

[dannobee]

Chances are pretty good that you'll be limited to what tanks the liveaboard supplies (unless you're bringing your own tanks). It would probably be wise to use what is available on the boat.

If you're considering a pony tank, I'd suggest buying something like this (https://www.deepseasupply.com/index.php?product=1309), then just rig up a standard AL80 tank as a stage bottle. That should give more than enough gas for you to stay down as long as your better half.

If you choose this route, by all means, practice a few times before you go on vacation. It doesn't take much time to get used to it, but it is different than just a single tank on your back.


.

[Steve, SDI/TDI HQ]

Hello all,

I am AOW with 50 dives.

My wife and I are planning another Liveaboard in the Red Sea in April :D, the problem is that in terms of size we are significantly different (me bigger and taller). Even with me using a 15L tank I need a bit more air in order to extend the dive.

I know that my consumption rate will get better in time, but so does hers and trust me, she is small and she is "very" efficient on her air.

So the question is this: If the LDS provides the twin set and have a suitable BCD, do I require any training to use the twins other than the tech brief on the actual valve system?

Thanks in advance.

Richard

What you need most I believe is training in dive planning and a better understanding of gas management... you wearing doubles does not give you a safer cushion should YOUR kit develop an issue and you have to share gas with your buddy.

And, yes, if you're thinking of diving doubles for the first time on a vacation, you will most likely have a rotten vacation.

Almost certainly, your "high" consumption has its seat someplace other than your size... if you are far from about 12 litres or 0.4 cubic feet per minute, work on two things... learning to breath (and relax) and improving Cardio-vascular fitness.

Read this for some background: http://decodoppler.wordpress.com/2009/02/02/the-six-basic-skills-number-one-breathing/