Longer cylinder choice for 6' 1" diver...!

[matthewm]

Hello all.

I'm looking for some other diver experience to help me make a decision about upgrading my back gas.

I currently dive short? 2 x 10 manifolded but isolated. More on this later.

I picked up this twin set for a bargain price right after training and my consumption was high.

I dive 1 or 2 times a week and most dives are shore dives to 20-30m range and a slow ascent along the reef.

Most of our dives are around the 60-90min mark and I'm coming back with 40-70bar

We are happy with the dive lengths and the decent amount of back gas.

The problem. These cylinders I have are quite short. If I sit back on a wall to rest while kitting up the bottoms do not touch the wall. If I reach back I can't reach my valves. I need to hoist the cylinders forward to reach. Not ideal. But okay in emergency.

Clearly the cylinders are too short for my back.

I really really enjoy the isolated/twin set-up. I just switch regs at 100 bar and breathe the second cylinder right down to 50bar and then switch over if needed. Most dives are complete before then so I only end up switching the first time. This gives me great redundancy and peace of mind and it is no hassle to change regs.

I think 2x12's would be really overkill for my dives and much heavier. A bit lighter would be better!

So, I am looking for options on longer cylinders? Are there longer skinnier 10's? How do I find out the correct length cylinders for me? Should I just live with what I have!

Thanks for any ideas.
Matthew

[ChristianG]

The problem. These cylinders I have are quite short. If I sit back on a wall to rest while kitting up the bottoms do not touch the wall. If I reach back I can't reach my valves. I need to hoist the cylinders forward to reach. Not ideal. But okay in emergency.

Clearly the cylinders are too short for my back.

I really really enjoy the isolated/twin set-up. I just switch regs at 100 bar and breathe the second cylinder right down to 50bar and then switch over if needed. Most dives are complete before then so I only end up switching the first time. This gives me great redundancy and peace of mind and it is no hassle to change regs.
A couple of things spring to mind.

If I understand what you said correctly I suggest that you are not using your independents as most people would. The whole idea of independents is that you breathe them down in turn so that if there is a catastrophic failure of one there is still a decent quantity of gas in the other (as best as can be managed). In my case I breathe them down, in turn, in 50 bar increments, more or less.

My cylinders are very short indeed, and I'm 188cm, an inch (in your language) taller than you are. Yes, sometimes I find that uncomfortable and wish I could rest them more easily, but not unduly so and I can reach the valves (they do not run parallel to my back but away from it).

Somebody will probably come along with the name of a tank which is long and skinny, but that's not really the point. Diving, like everything else, is a compromise. You like 10 litre tanks but they're too short for your frame? Tough, get used to it.

More importantly, please allow me to suggest that you breathe those tanks down in lesser increments.

[Fiona]

I found kitting up in twin 10's too short and I am only 5'5", I now dive euro twin 12's which are slightly longer than the fabers and they are fine. If you are happy with 10's look at the Halcyon/Euros.

Your choice but not sure why you are diving a manifolded set as independents.

[Janos]

Your choice but not sure why you are diving a manifolded set as independents.

Ditto your choice. But I would also consider swapping regs on the bottom. That way you know the first reg is working because you breathed it on the way down, and the second reg is working because you've just switched to it.

Janos

[DarrenA]

Do you know how heavy your current setup is minus regs?

A 12L Steel Faber is about 16Kg empty. Twins with manifold about 35Kg.

You could always ditch the manifold as you dont use it?

Might be worth checking the weight of yours though. I have seen older steel cylinders weigh a great deal more than newer ones.

For the record, I dive twin Faber 12's with manifold and my wife dives the same. I am over 6', she is 5' 1".

Shore diving with a rocky entry and exit would be interesting though ;)

[ChristianG]

I should also point out that whatever weight you might shave off your cylinders would, if already correctly weighted in the first place, need to be added to your weight system? Never mind what alternative cylinders (that are lighter) that you might employ in the future.

[DarrenA]

I should also point out that whatever weight you might shave off your cylinders would, if already correctly weighted in the first place, need to be added to your weight system? Never mind what alternative cylinders (that are lighter) that you might employ in the future.

Good point. Very true.

[Nick Argue]

I'm 6 foot and dive faber 10's with no problem sitting down with them when kitting up. Are they mounted on a jacket or a backplate and how high?

[MarkM]

I'll dive anything, and I do. 300B 7's may be an option for you. Taller than 10's, similar gas volume, similar weight but you can take several kg's off your belt. Biggest problem is 300B fills & regs if you don't have 300B regs..

[Craig]

Matthewm - I am the same height as you and used to dive twin 10's and am considering going back to them (but thats another story).

I inverted my twin 10's and put a Custom Divers Halo on them. This made them a reasonable height to put on when sat down but also made shutdowns very easy. I didn't manifold them purely out of choice but again it would make the isolation valve easy to reach.

[matthewm]

Thanks for all the replies. For some reason I am not getting email updates so sorry for my late reply.

Weighting...
For the summer in my wetsuit the weight is perfect with a Aluminium plate so I don't take extra weight. Weight is not really an issue as I'd have to replace with lead or my steel backplate anyway.

Manifolds...
The big problem is the height. In my dry suit I cannot reach my valves full stop. The cylinders came manifolded and I can't use them. Only in extreme I'd need to do some fancy half removal of the harnass to get to the Valves not very ideal under stress. So I dive them closed so I am not under pressure to get back to the gas.

So the main reason for the closed manifolds is the inability to reach them.

I've tried the 2x12's and I can reach those valves fine.

Gas management...
Off topic but, my reserve is always enough to get back. Breathe the first to 100bar then change over. If the worst happens and I lose the 100side, I still have the 220 side. If I lose the 220 side I still have the 100 side which is more than enough to make a return to surface with stops. If my 2nd side is down to the 50bar for the second change I have 50 + 100 and practically under the ladder anyway. So 50 bar is lot of air at 3m. I see nothing wrong with this practice given my dives profiles. Certainly a lot safer than most divers here on 15ltr onlys.

I have the bands as high as possible on the cylinders and then mounted as low as possible on the plate. Any higher up and trim goes wrong anyway if the cylinders get empty due to the bum up tendency of empty cylinders. The last thing I want on a bad dive is empty cylinders and bum up trim.

Upside down is one option but I'd need to replace some or many of my hoses plus the cage so a good price towards replacement cylinders.

I am thinking about 300bar so I can have skinnier taller cylinders but I don't know which ones. 7's seem pretty close.

I just found out the registered section of the Faber site has technical drawings to include the height of their cylinders!

Twin 12's the UK option is overkill here! I'd like to know your dive profiles that require the Twin 12's?

Thanks for the tip on Euro. They have a 8.5Ltr 232 same height as a 12 but 140mm dia.
http://www.silentplanet.info/diving-cylinders/cylinder-specifications

And the 300bar x 7's.

When I get some good options from the Faber specs I may have a good set of options.

Regards and thanks,
Matthew

[AndyA]

These would do the job, but not cheap and only ever seen 1 set up for sale second hand.

http://www.dirdirect.com/8.5L-Eurocylinders-Twinset.html

[matthewm]

I went through the Faber spec in details and found this selection of cylinders that may be useful for other people with the same height problem as reference:

8ltr 140mm dia 675len 300bar 10.5kg (2,400 litres) 228 litres per kg
9ltr 140mm dia 725len 200bar 8.8kg (1,800 litres) 204 litres per kg
10ltr 140mm dia 800len 200bar 10.0kg (2,000 litres) 200 litres per kg
10ltr 152mm dia 690len 200bar tbc (2,000 litres)
10ltr 171mm dia 575len 232bar 12.4kg MINE (2,320 litre) 232 litres per kg
11ltr 140mm dia 875len 200bar 10.4kg (2,200 litres) 211 litres per kg
12ltr 140mm dia 940len 200bar 11.0kg (2,400 litres) 218 litres per kg
12ltr 171mm dia 670len 232bar 14.4kg (STD 12Ltr) (2,784 litres) 193 litres per kg

What I see interesting is the 300bar 8's are lighter 'in air' than my 232bar 10's.

Also the 200bar 12's are also lighter 'in air' and hold more air!

Hope this helps others as well.

Regards
Matthew