Bail out cylinders are people using.

[quickean]

I have a few 80's and 40's, but I love my aluminum 72's. Might eventually replace all my 80's with them. Was first introduced to them by Wayne at Amigos and Mel. The buoyancy characteristics are close to a luxfer 40 and the diameter is a little less than an 80. They actually hold 72 ft3. An 80 actually holds 77 so there's only a 5 ft3 difference. If you're going to take 3 or 4 of them to stage in a cave or for deep bo I'd much rather the 72s.
I always sidemount them, and I can actually tell a noticeable difference between swimming with 2 80's verses 2 72's. Feels like you're slicing through butter.

 

[alin]

Slightly off toppic... If you're doing a serious dive (2, 3, 4 stages), the best is to do a weight check with the stages empty. If the crap hits the fan, you don't want to be struggling to do the last stop head down and finning all the time. Most of us are carying the bail out tanks full all the way and at the end of the dive the tanks are still full. Neutral buoyancy, nice, all dive time ccr, it works sweet. But how many are checking the weights right? Why are we carying the bail out? I didn't had to bail out and use 4 stages but I have made a weight check with 4 stages, all on 50 bars. Believe me, it's a big diffrence. Try it once, you'll be surprised.

My 2 cents...

All the best.

alin

 

[seppu]

10 l steel for tmx 7/75 to 16/45 250 bar bottom gas
80 cuf ali 20/50 and 32/30 220 bar travel gas
12 l carbon steel 50/20 320 bar deco gas
6 liter full carbon for oxy 250 bar deco gas

why?
left side front
inside 50/20
outside bottomgas
left side back
20/50 and oxy

right side
heating vest and drysuitgas.
and space for the scooter in the front .i dont like to clip it in the hip ring

 

[Tiptopperoo]

Slightly off toppic... If you're doing a serious dive (2, 3, 4 stages), the best is to do a weight check with the stages empty. If the crap hits the fan, you don't want to be struggling to do the last stop head down and finning all the time.

alin

The beauty of the Alu tanks is that you can just send them up the line when they get light. There would be no reason to hang on to 4 empty and positively buoyant tanks.



Sent from my HTC Desire S using Tapatalk 2

 

[Dave Sutton]

The original poster as per personal conversation is interested in bailout for his Mod-1 course work.

One Alu 80 will do.

Interesting about the 72's. I'll borrow a few from Wayne at Amigos next time I'm there and have a play.



Dave


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[quickean]

Interesting about the 72's. I'll borrow a few from Wayne at Amigos next time I'm there and have a play.



Dave


.

For sure! Gaurantee you'll like them.

 

[Mark Chase]

The beauty of the Alu tanks is that you can just send them up the line when they get light. There would be no reason to hang on to 4 empty and positively buoyant tanks.



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Two things concern me.

1 is: What about the 15mins of breathing the floaty thing just before it is empty and sent up the line?

2: Are you seriously going to send up £1600 worth of equipment in a rough sea on a SMB line?



Personaly I prefer the feetures of steel when empty. Light weight Fabers 7s & 10 just float neutrol in salt water empty with a single reg and a DS4 on them.

I have dived with two steel 10s and a steel 7 all prety much 50bar or less at the end of the dive (on OC) and thers no boyancy issues. Back in the OC days jumpung in with twin 15s and two 10s i used to love the way I could get down to 60-70m in a few mins thanks to the extra weight of the gas.

By the shalowes where being overweight would have been an issue i have emptied 75%+ of all the gas and all my tanks go neutrol which is nice.

Id have careid on using steel for all gas on my CCR but with trimix in a steel 10 it floats when full, so the other one full of heavy nitrox puts you off balance. An Ali 80 still sinks but its not so bad.



This is in fresh water but see how the steel 10 floats arse in the air with 260bar of 1845 in it and the Ali 80 is flat on the deck with 240 bar 50% in.

The Al80 is about 3lb neg with no reg on it and about 6lb neg with a reg on.


The steel is about 1.5 lb neg no reg and obviously 4.5lb neg with a reg on.

 

[YobazEfendi]

If a containeris neutral when empty, it is not possible to put some thing in to it and make it float.

Unless you stretch the boundaries.


What you mean might be that 50 bars of air is heavier than 260 bars of trimix?

 

[quickean]

Helium is lighter than nitrogen and will make bottles less negative/more positive in the water.
The bottom end of aluminum 80s with a rich helium mix will have a tendency to float up.

 

[YobazEfendi]

I am also a fan of the steel cylinders. Especially the hp ones.

Right now I am using a 6l filled to 320 bars and a low pressure one with nitrox or o2.

I added a bit of foam to the hp one. To make it less negative. In a real emergency I can take the foam off.



Teoman

 

[jcook]

Is anybody carrying steel tanks like maybe 85s or 72s for a little extra weight

Yes, I use faber steel lp85's (13L) and I just got a set of faber lp50's (8L) for some shallow(er) cave dives. AL80's are terrible for cave diving, too floaty when they are empty. I don't like to carry weight with me, the steel tanks make up for that. To quote Forrest Wilson, "You can't breathe lead." So why not use a tank that is the exact same size as an AL80 or AL72 and you can get a bunch more gas out of? Just doesn't make sense not to use steels when cave diving. I can see why you wouldn't want to use steels when wreck or just ow diving, but I don't do that.

No. Not anyone with any sense.

You should come for a visit and I can show you how we rig Alu 80's as side mounts for bailout. You DO NOT want them "hanging heavy". They ought to be tucked up high and behind your arms.

As you would say Dave, that is complete rubbish. I have my steels on my sidemount harness, just like the majority of the rebreather cave divers in FL do. My steel tanks are behind my armpits and parallel with my body. Why don't you come visit us and we can show you how it is really done?

 

[kosh]

AL80's are terrible for cave diving, too floaty when they are empty.

You must be bail-outing a lot?

If i ever would need to use my AL80´til empty i just leave those clipped to line and pick them up later. I don´t use any lead with my rEvo so why would i want to be more negative with steel tanks?

 

[jcook]

You must be bail-outing a lot?

If i ever would need to use my AL80´til empty i just leave those clipped to line and pick them up later. I don´t use any lead with my rEvo so why would i want to be more negative with steel tanks?

Have you ever had to bail using 2 AL80's while cave diving? I have, I had to flood my unit to peel myself off the ceiling of the cave. I guess I could've just spider-man-ed it out, but I wanted to be able to swim out of the cave.

 

[JukkaO]

Interesting to read so many different views about the cylinders.

Buoyancy control is about the first thing one needs to learn when diving. It just needs to be planned and tried how to use more cylinders.

We prefer old light steel 1, 7, 10 and 12. Round bottom just looks better.

Jukka

 

[kosh]

Have you ever had to bail using 2 AL80's while cave diving? I have, I had to flood my unit to peel myself off the ceiling of the cave. I guess I could've just spider-man-ed it out, but I wanted to be able to swim out of the cave.

Well, i can still get myself slightly negative without any BO tanks and without flooding my unit so i guess situation is little bit different with other gear. Also if i ever would need to change tanks with BO:ting team member i would´nt like to hand over my "weights" with my tank. Or in restrictions, pushing negative tanks in front of me with me being positive does´nt sound good idea to me.

 

[jcook]

Well, i can still get myself slightly negative without any BO tanks and without flooding my unit so i guess situation is little bit different with other gear. Also if i ever would need to change tanks with BO:ting team member i would´nt like to hand over my "weights" with my tank. Or in restrictions, pushing negative tanks in front of me with me being positive does´nt sound good idea to me.

Again, I am just speaking for cave diving. Also not everyone dives with other people, I mainly dive solo so there is no getting a mate's tank in a bailout situation. Plus swapping properly sidemounted tanks out underwater isn't a pleasant experience. I also have my rebreather setup to take off underwater now, so I can push it in front of me to get through a restriction or just ditch it in the event of a total failure. I just clip it to my sidemount harness and plug into my bailout gas, then I am ready to go again.

Pushing negative tanks out in front of you to get through a restriction really isn't a problem. I just keep mine bungeed to me and clipped to my front d-rings. It is basically like having a pivot point on my harness. If you need to see a video of it, send me a PM.

 

[kosh]

Again, I am just speaking for cave diving. Also not everyone dives with other people, I mainly dive solo so there is no getting a mate's tank in a bailout situation. Plus swapping properly sidemounted tanks out underwater isn't a pleasant experience. I also have my rebreather setup to take off underwater now, so I can push it in front of me to get through a restriction or just ditch it in the event of a total failure. I just clip it to my sidemount harness and plug into my bailout gas, then I am ready to go again.

Pushing negative tanks out in front of you to get through a restriction really isn't a problem. I just keep mine bungeed to me and clipped to my front d-rings. It is basically like having a pivot point on my harness. If you need to see a video of it, send me a PM.

Ok, i´m talking also about cave diving but now i understand.
You dive solo and never ever hand out your side mounted BO tanks and your rigging is positive in water without extra weight.
I dive always with buddy/team. I have option of handing out my side mounted BO tanks. My rig is slightly negative without any weights.
Just out of curiosity which unit you dive with?

 

[jcook]

Ok, i´m talking also about cave diving but now i understand.
You dive solo and never ever hand out your side mounted BO tanks and your rigging is positive in water without extra weight.
I dive always with buddy/team. I have option of handing out my side mounted BO tanks. My rig is slightly negative without any weights.
Just out of curiosity which unit you dive with?

A Meg.

 

[Dougyfresh]

Is anybody carrying steel tanks like maybe 85s or 72s for a little extra weight

Sometimes we bring a lp 85 blown to 3600 psi if we want a little extra bottom mix.
You will mostly see al80s and al40s up here.

What boats are you diving from? And which unit?

 

[Dave Sutton]

As you would say Dave, that is complete rubbish. I have my steels on my sidemount harness, just like the majority of the rebreather cave divers in FL do. My steel tanks are behind my armpits and parallel with my body. Why don't you come visit us and we can show you how it is really done?

I'm sure you and I are rigging the same way "when I can" (which is not always the case).

The original poster is a local diver who will be taking his Mod-1 soon, and my answer was to him, for our local environment, for what will soon be his level of training. Sorry if that was not clear.

Dave

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