Best twin tank for not tall guy ?

[paddydiver]

I don't know your air consumption but if you are diving air to 50 - 60 m I don't think your supply will be the limiting factor unless you are planning a very long deco with just your back gas. That extra 4l might be better in a deco tank....

 

[Vitesse2l]

I've borrowed short Faber twin 10's and they are easily the worst set I've ever dived in. They are far too short for comfort. You can't sit down in them because the base is about 6 inches off the ground so all the weight is on your back all the time

That's pretty much what I was told when I was researching before I bought my 12's. They do need to be reasonably high so the valves are in reach under water.

 

[lizardland]

I don't know your air consumption but if you are diving air to 50 - 60 m I don't think your supply will be the limiting factor unless you are planning a very long deco with just your back gas. That extra 4l might be better in a deco tank....

Getting two people from 60m to a gas switch at 21m is going to burn at least 30 bar of gas, probably more like 40 or 50. That's a direct ascent, no finding the shot, no fannying about with an SMB. Knock off another 20 bar for cooling and for the gas your regs will struggle to access and now you're down to 170bar for the dive. I use about 15l/min so that's 32min at 60m ripping the arse out of a 10l twinset with nothing to spare. That's not a dive for me.

Doing the same dive on twin 12's gives 40'ish bar/960'ish litres of comfort. That's the difference between being able to come up the shot, having plenty of divers around you and knowing the boat is parked above you or alternatively having to shoot a bag from wherever you are and hoping for the best. I know what I'd choose. For the sake of a few quid and 90mm?

Plus you have to decide whether you are buying new kit based on your diving today or the diving you're planning on doing in the future. If I had even a glimmer of doing full trimix in the near future I wouldn't touch 10's. They really are at the bottom end of adequate at 55-60m.

 

[BoltSnap]

If you are doing strictly recreational diving, Twin 10L tanks are OK; that's what I do. But for technical diving at the depths specified, no way for me. I go with twin 12L tanks.

 

[sharko108]

Can you swim up all that weight in case of a wing failure at depth and full tanks?

I've learnt to ascent with dsmb in case of wing failure + dry suit

I don't know your air consumption but if you are diving air to 50 - 60 m I don't think your supply will be the limiting factor unless you are planning a very long deco with just your back gas. That extra 4l might be better in a deco tank....

No of course not air only , air bottom gaz + 1 deco but if only 1 deco i plan in case of deco fail that i can do the full deco with bottom gaz

Getting two people from 60m to a gas switch at 21m is going to burn at least 30 bar of gas, probably more like 40 or 50. That's a direct ascent, no finding the shot, no fannying about with an SMB. Knock off another 20 bar for cooling and for the gas your regs will struggle to access and now you're down to 170bar for the dive. I use about 15l/min so that's 32min at 60m ripping the arse out of a 10l twinset with nothing to spare. That's not a dive for me.

Doing the same dive on twin 12's gives 40'ish bar/960'ish litres of comfort. That's the difference between being able to come up the shot, having plenty of divers around you and knowing the boat is parked above you or alternatively having to shoot a bag from wherever you are and hoping for the best. I know what I'd choose. For the sake of a few quid and 90mm?

Plus you have to decide whether you are buying new kit based on your diving today or the diving you're planning on doing in the future. If I had even a glimmer of doing full trimix in the near future I wouldn't touch 10's. They really are at the bottom end of adequate at 55-60m.

32min at 60m is still a nice bottom time isn't? I mean its not like it was a touch and go ? But as i said its not about a weight/volume issue but confort underwater.. if it's really a disconfort i can't get used to, the dive will not be pleasant with 12 even if i've more air lol but of course i'll try again twin 12
And no i'm not going trimix in OC , later when i'll be on CCR

 

[sharko108]

That's pretty much what I was told when I was researching before I bought my 12's. They do need to be reasonably high so the valves are in reach under water.

But is there really short 10? I mean usually on reseller , it's just twin 10? Doesn't really seem that short , kinda like a 15L ?
And what is the real problem about not able to sit with it? Few people said this , but you usually don't really wait that long in that position ? Just to gear on/off , like less a minute?

 

[inquis]

air bottom gaz + 1 deco but if only 1 deco i plan in case of deco fail that i can do the full deco with bottom gaz

Have you planned any dives within the constraints of the D10s?

 

[sharko108]

Have you planned any dives within the constraints of the D10s?

I could be wrong , i'm still new for this but for example max depth 60m difference bottom time between D12 and D10 would be around 3min, 4min for 40m

 

[lizardland]

32min at 60m is still a nice bottom time isn't? I mean its not like it was a touch and go ?

I think you're missing the point. That's your max time with no leeway. Problems are like pregnancies, they never happen when it's convenient. You can guarantee Monsieur Murphy will come knocking at 31 minutes and 58 seconds and at that point you are going up. Your gas planning now has no scope for returning to the ascent line and probably no spare gas for shooting a bag until you reach your first gas switch. Personally, if I was planning this dive, I'd be looking more at maybe 25 min bottom time. Meanwhile everyone with 12's is doing a longer dive with more of a reserve.

But as i said its not about a weight/volume issue but confort underwater.. if it's really a disconfort i can't get used to, the dive will not be pleasant with 12 even if i've more air lol but of course i'll try again twin 12

Yes, part of it is finding comfort. But part of it is also getting used to a bit of discomfort too. Not many people enjoy deco but if you want to do certain dives then you have to eat a **** sandwich. Diving is rarely perfect.

It's your choice. You have to prioritise what you think is most important to you. Everyone is different. For me, 10's for that kind of diving is a compromise too far.

And no i'm not going trimix in OC , later when i'll be on CCR

So are you planning 50-60m dives on air? If so then I'd want to give myself as much reserve as possible. You really don't want to be dealing with stress, narcosis, dense gas and potentially being a bit low on air as well all at the same time if you are faced with an emergency. That is a disaster waiting to happen.

But is there really short 10? I mean usually on reseller , it's just twin 10? Doesn't really seem that short , kinda like a 15L ?

Faber do/did short 10's, shorter than the Euro 10's are. I don't know how available they are now. They were popular in the UK at one point (I don't know why) but they really are awful to dive with. I doubt many people buy them now.

The problem with short cylinders is your arse needs to be lower than the base of the cylinders to get your harness on. This is really awkward on a boat bench and really hard on your back when you try to actually get up into a sitting position. Like you will **** your back up eventually with them.

Plus they sit higher up your back in the water. I found it put a lot of strain on my lower back when I used them. I've never had that with longer cylinders, even with 20's.

 

[Vitesse2l]

And what is the real problem about not able to sit with it? Few people said this , but you usually don't really wait that long in that position ? Just to gear on/off , like less a minute?

This is where my experience of twin diving probably differs from yours!

When I'm boat diving its normal to sit on a bench or rib tube to kit up. This can take me a while to achieve. Once strapped into my 12s I'm comfortable. Add on a stage or bailout and comfort reduces. Then wait for the boat to get into position...

Again, just my own experience of UK drysuit diving. If you are able to make your choice of equipment work for you then it's all good.