What size stages

As for the specs from DGE, I never looked closely, but something seems awry. Buoyancy difference between empty and full should clearly be the same for all tanks of the same size, regardless of composition. And should be directly proportional for different size tanks. So the 4.8 pound difference for an aluminum 80 (even at only 78 cf) should equate to at most a 5.2 pound difference for the LP85 rather than the 6.1 pounds they show. I'm not sure where the problem lies.

As for letting go of empty cylinders, I'm ok with it if the tank is truly drained. But the problem occurs when it is still half full (or in Garth's case half empty) and I am very reluctant to release it. In my normal environment of wreck diving from a boat, the tie in is connected to a Carolina rig. So anything you clip on at depth will be trapped by that connection and you can tend to it when you get there. Then send it up to the surface, still secured to the boat and get it later. If ascending on your own upline, it should be waiting for you at the surface unless it manages to sink your bag.

I need a lot of lead to counteract my buoyant personality and large amounts of "bioprene," so steel bailouts are the way I choose to go.


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Sorry if I am jumping in this late, but I think you will find yourself in a situation where you will end up throwing gas in case you dont do the same dive profiles all the time.

For example if you have trimix gas in your cylinders and you are doing a 40m dive for 1, 1,5 hours, what are you going to do? Empty the helium and do a better mix?

So my advice is keep the tanks. Maybe you will be banking gas.

I have 4 s80s, 4 7s, 1 s40 all for myself. I make all sorts of variations according to the dive profile. Off course, I maybe wrong, but I am guessing that you ll end up having same issues.

All the best....

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Yes seems sensible I have some twin 10s I try to do most dives on 17/45 seems to work for my style of diving,I was thinking of using the 10s to decant out of for my dil and keep a 7and a 11 with 50 % nitrox then use the other 11 and 7 for bailout but I agree I could end up long term losing gas
Looks like a booster pump is going to be needed long term and some 15s to store gas
Oh she will be happy
 
kwinter said:
As for the specs from DGE, I never looked closely, but something seems awry. Buoyancy difference between empty and full should clearly be the same for all tanks of the same size, regardless of composition. And should be directly proportional for different size tanks. So the 4.8 pound difference for an aluminum 80 (even at only 78 cf) should equate to at most a 5.2 pound difference for the LP85 rather than the 6.1 pounds they show. I'm not sure where the problem lies.

As for letting go of empty cylinders, I'm ok with it if the tank is truly drained. But the problem occurs when it is still half full (or in Garth's case half empty) and I am very reluctant to release it. In my normal environment of wreck diving from a boat, the tie in is connected to a Carolina rig. So anything you clip on at depth will be trapped by that connection and you can tend to it when you get there. Then send it up to the surface, still secured to the boat and get it later. If ascending on your own upline, it should be waiting for you at the surface unless it manages to sink your bag.

I need a lot of lead to counteract my buoyant personality and large amounts of "bioprene," so steel bailouts are the way I choose to go.


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This made me laugh hysterically. I am usually very optimistic about things so I don't know where I came off "half empty."

I have a Feeling DGE is a little bit off but figure I will try actual tanks to see how they behave.

This leads me to my next question... If you overfill a steel low pressure tank to 3,500PSI ... What pressure would it be at when it is half empty? Or half full?

Garth :-)


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antsdd said:
Hi
Just a question I dive a inspiration classic currently trained to 60 mtrs
I am planning my advanced mixed gas later in the year
My dilemma is I currently dive with either 2 x7ltr stages or a 11bailout and 7 deco
I was thinking of going to two 11s but I get earache of the wife with my collection of cylinders
Do I sell the 7s and stick with 11s all the time or keep the 7s too
Cheers anthony
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I like LP50's side, filled to 4000 PSI, it gives you a lot of gas

For stages clipped off or towed in on a leash I like AL 72's, great buoyancy.
 
kwinter said:
I hope everyone keeps in mind that choosing bailout cylinders should also include a plan for using them. If you have to bail out, you will be using the gas and therefore become more buoyant. With aluminum bailouts, some choose to remove empties and let them float up the line (assuming no overhead), but with steels this would make you even more buoyant. There is no one right answer for all situations. Just suggesting that you take the complete bailout picture into your plan when deciding about the cylinders and weighting.
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+1

All Alum.
4 80Cfs... High HE mixes I use a cam band with a 1KG near the bottom, to off set "the floaties"
4 7lt.
2 40cfs.

Most all gases have a little HE in to make them near neutral B. Great when sidemounting B/O tanks.
 
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Ken, I guess sending up an empty on a Carolina rig is convenient as, presumably, there are unlikely to be knots or splices on the anchor rope which would hinder this. In the UK, we commonly descend on a shot line which can be made up from a series of short (30 metre) lengths comprising the approximate depth. Of course, these knots would entangle an empty. Also, shot lines are frequently recovered by the dive boat a few minutes after the last pair has descended and the boat maintains station using a chart plotter or GPS. Divers then make independent ascents under SMBs sometimes over a considerable period of time depending on whether they are on OC or CCR. On occasions when we are diving in the shipping lanes, ie. Mid-English Channel we choose to deploy a deco trapeze to group all the divers and to allow comfortable deco on the drift. I've not used a Carolina rig and I imagine that it would be less than ideal in strong currents, ie. Ascending after slack water.
 
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There is no standardization here either. That's why we all need to think about these things before we dive. A few extra pounds of lead if using aluminum and not in a position to jet the empties. I also use cam bands with weight on the bottom of aluminum tanks, but prefer steels. So does the boat crew, who hate lifting the Al 80s with 3 pounds strapped to them.


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Captain Starfish said:
Never sell a cylinder - the day you do, you'll need a new one.

Consider this: the space vacated in your bed by an ex wife will typically accommodate four al80s and probably a couple of al40s as well. Cylinders are typically a hell of a lot cheaper to maintain, too.
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For some that's a good move....for me, it was a great move.
It freed up space for a Meg, some dive training, and a few trips.

It's amazing what happens when you don't have one bleeding you dry.
I now know what being debt free feels like.

Truth!
 
I sold my double HP120s for my bailout off board gas connects. Another bailout cylinder and a few other bits and hoses.

I am glad I sold them.

Now I need some LP50's....


Garth
 
Garth said:
I sold my double HP120s for my bailout off board gas connects. Another bailout cylinder and a few other bits and hoses.
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Bad move. Like Starfish said, never sell a tank. Those HP120s are a great way to bank gas.


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kwinter said:
Bad move. Like Starfish said, never sell a tank. Those HP120s are a great way to bank gas.


Please pardon any typos. Sent from my iPhone using Tapatalk
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That's a good point which I thought of but chose to sell since i have a buddy with great supply of helium and oxygen with compressor and large booster.

It's worked out well so far but I see your point. Wasn't an easy decision although I knew I was done using them for diving.


Garth
 
I have 2 x 7 lt cylinders for use to a max depth of 50m and 2 or 3 x 11 lt cylinders for deeper dives as required with additional drop cylinders if needed.
 
I have just ali80's. Don't need others. I already had them for oc diving. Now use them for ccr diving too. Suitable for all diving, deep and caves.
 
207 bar Ali 80's and 40's from Luxfer, great tanks. Catalina's are arse heavy, 230 bar have poor buoyancy characteristics. If you can only pick 1 type, go bigger. Better to have more gas than less and you don't want to stretch the bailout figures to make 7l fit the dive profile.
 
I dont even bother to carry 40's anymore,and just dive one configuration with 2 80's. If I need more BO gas than the 80's, we hgo team bail out, or I carry my BoB.
 
Always better to be looking at the gas than looking for the gas. Bail gas calcs give u a fair idea then add more for heightened rates
 
Captain Starfish said:
Never sell a cylinder - the day you do, you'll need a new one.

Consider this: the space vacated in your bed by an ex wife will typically accommodate four al80s and probably a couple of al40s as well. Cylinders are typically a hell of a lot cheaper to maintain, too.
Click to expand...

I used to keep a set of doubles, 3 stages, and 2 40's under my bed when I lived in a tiny apartment. Now I have a living room to store my 30 or so cylinders because I do not have a TV....
 
NorthWoodsDiver said:
I used to keep a set of doubles, 3 stages, and 2 40's under my bed when I lived in a tiny apartment. Now I have a living room to store my 30 or so cylinders because I do not have a TV....
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Yet he complains to me and asks why he can't find a girlfriend..........
 
jcook said:
Yet he complains to me and asks why he can't find a girlfriend..........
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I know why I don't have a girlfriend and it isn't because I have 31 cylinders in my living room at the moment. They don't make it to the house to find out about the scuba gear, most of the time. Thanks Jordon
 
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