Deco bottles on one side WHY?

[trymixdiver]

Why is carrying a deco or stage bottle on each side considered strokery ? using the following :

1. If your not cave diving and not carrying a canister light

2. Your not wreck diving or penatrating

Give me some good reasons why i cant use a deco bottle on one side and a stage other side.

Andy

 

[trymixdiver]

If i choose to use a stage bottle and a deco tank why cant i carry them on each side. I can understand if your using a canisterlight, but i dont. whats the reasoning for carrying them on one side only if your not carrying a canister light.

Andy

 

[ScubaSteveC]

Most people who dive with a stage/deco bottle on each side do so as a means of identifying the proper gas for a certain depth. Say on my left is my 20' (100%O2) bottle and on my right is my 70' (50% O2) bottle. Using the right and left method adds a window of error of breathing the wrong bottle at the wrong depth.

DIR marks the bottles with 3" numbers (i.e. 20 OXYGEN, 70, 120, 190) to identify at which depth the gas can be breathed. Notice the 20' bottle is also marked OXYGEN to prevent someone thinking its a 120 bottle.

With the tanks marked in this manner and located on the left side you can look at the bottle to make sure you can breath this gas at this depth. This also allows your buddy to double check your gas and depth.

 

[Lost Yooper]

Hey Andy,

It basically comes down to drag and hose routing. The WKPP guys have done time trials to determine their efficiency in the water with various bottle configurations. Even without scooters, they found that having all the bottles on the left side was more efficient than having one on the left and one on the right. If you've ever noticed, you'll get a side to side motion going while you are kicking with a bottle on each side. This is inefficient and we all know what happens with inefficiency.
Then you have hose routing considerations. The reg you're breathing from always comes from the left, behind your neck and into you mouth. Having a bottle on the left makes hose routing a bit "different". Of course, as stated above, you don't want to have a "system" of bottle placement solely for the purpose of bottle ID. This can lead to an ugly screw up.

Take care.

Mike

 

[ScubaSteveC]

I was thinking about including that, but only looked at the increased drag if you were scootering.

When scootering the scooter actually breaks the water. Your body is within the water "break" and with the stage/deco bottles tucked in behind your body you don't create an further drag.

Thanks again Yoop

 

[AquaTec]

Yoop
Leaving the scooters out of it [for now]

I use a stage bottle on each side.
I have even been know to have two on each side

My standard kit would include an aluminum 80 on each side, I sometimes add an al 40 on top of that. based on gas requirments.
I am now toying with the idea of using Faber 95's as stage bottles. I havent tried it yet but i like the nutraul boyancy and the added gas.

I set them up as so;
each tank has on it labled the contents and the MOD
the tank valve handles are possitioned to be facing towards my middle. in other wards I use a left hand or a right hand valve depending on what side the tank is on. DIN of course

On the first stage is a 6" hose with a pressure gauge atached
also a second stage with a standard length hose

the excess hose is tucked into surgical tubing on the tanks.
and the reg itself is held to the first stage with a looped bungy.

I personaly always have the highest PPO2 on my right side. but this is just a case of standardisation on my part. I always rely on the markings. my 80/20 bottle has a mouth piece cover to avoid mistakes. so does my 100%

When I use one of my stage bottles I don't run the hose around my neck. mostly because I never thought of it. i will try this tomorrow. I have never had any disconfort with reg usage from either side

everything is attached to me with soft connections.
and I beleive in were I go my tanks go. I don't ever leave them outside a wreck. mind you I have to remove them ever so often. but I usualy just undo the bottom atachment and swing them down towards my crotch underneith me. or slide them out front.

I can do this slowly and still work the line

I have not noticed this swaying action you speak of when swimming with tanks on each side.

Tomorrow I will be diving with six tanks including my argon bottle
I have also been looking at the way they are doing things in the UK and that is to strap a third tank on your back between your doubles. I have a friend who dives this way.
I am considering putting an intermedait helium mix there. I just haven't thought it all the way through yet. or maybe my 100% bottle

with an intermediat He I could raise the He% and lower the O2% in my bottom gas say for dives deeper than 350ft

Then for the intermediate raise the O2% and lower the He% use that say between 100 and 300 thus start the flushing of He out without adding N2

with all this in mind I am also reading about shallow He for deco very interesting.

keep the bad boy N2 out of the system, then flush well with 100% at 20ft

I did get off track didn't I Sorry....what about those stage bottles anyways

The canister light is mounted to my backplate in a vertical posision tucked in out of the way. there is a good argument for it on your belt to protect it. but as it is it kind of tucks in behind my shoulders

 

[trymixdiver]

OK that makes sense

I will accept the drag reasoning, that would make sense. Based on this alone i accept the reasoning. However, i dont agree with the statement about useing the right or left side to determine your deco mix. I dont see this as a good reason not to to put bottles on both sides. I for one always looked to see my markings regardless of which side my bottles were on. You dont just blindly assume your breathing the right mix. Dont get me wrong, based on drag alone i wont be using a bottle on each side anymore, but not based on placing the deco gases on a certain side. I dont think deco bottle identification is a valid arguement, if your checking your markings before you use the bottle what difference doest it make if your using one on each side ( drag not being an issue of course).

having all deco tanks on one side i thought would be less efficent than putting them on both sides. It would seam that this is not the case. With deco tanks on both sides your having to push alot more water to get forward motion. This is due tot the fact that your mass with the tanks on both sides is increased. From what yooper has sent me it would appear that buy placing the deco tanks on one side will result in less mass to push through the water. Also, the tanks are going to be in relativily the same slipstream hence reducing drag compared to using both sides.
Andy

I also havent noticed this swinging of the bottles. I have video of some dives i did and they dont swing.

 

[Lost Yooper]

Hey Doug,

I don't have a problem visualizing what you're doing, but IMHO, I think you are attempting to solve problems that shouldn't exist in the first place and thereby introducing more potentially dangerous problems. I don't think it's a good idea to have things strapped to the back tanks for wreck diving because of the very real danger of entanglement and inexcessability.

I'm curious about how you go about the logistics of dives inexcess of 300'. For any substantial dive like that, I wouldn't do it without a competant support team (a couple divers) that could help out with bottles and what not. Take a look at GUE's Bitannic expedition for an idea of what they did for support and logistics

I'll tell you one thing for certain, there ain't no friggin' way I would have an o2 bottle strapped to my back tanks like you were talking about. People have croaked doing this because they get the regs confused and breath it at depth. This is a bad idea, Doug. The way I am visualizing your gear, I see it getting quite complicated which is the wrong direction for this type of diving. You have to look in the other direction and simplify your kit and streamline it.

As for the 95's for stages, I don't think this is a good idea either. Think about it, these things are -9lbs each full. I assume you're using double LP120's pumped up (-30lbs or so), you would look like a balloon underwater trying maintain neutral buoyance with 95's strapped to you. Not only would you be pushing a ton of water, you'd best hope you don't puncture your wings and/or drysuit. This isn't a good idea, Doug. Use AL tanks at the very least.

What say anyone else?

Mike

 

[nordicdiver]

Yooper, I am with you AL tanks are the way to go. I at one time
used steel 72's, After I switched to AL things became eaiser &
better ballanced.

Tanks on your back are a accident waiting to happen (never )

I do hang travel gas on the right, Like a 21/35 bottle. Everything

else goes on the left.

Just my 2 cents. Dive Safe Nordic Diver

 

[100days-a-year]

Have seen this question beat to death on techdiver.The answer in addition to LYs is about being able to continue scootering while handing off stages.These guys(WKPP)can drive with one hand and switch stages with the other.I personally wear a stage on either side if large ,but I'm considering using al40s as dive software is getting you out with less deco than years ago.2 40s on the left wouldn't be difficult for me to get used to.Access to canister light is by feel anyway so it was never a consideration.The new HIDs are smaller and even less weight to consider.