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*David Martin* · May 13th, 2008, 01:37 PM

Quote: (Originally Posted by BarryNL)

What would be the best choice for a stage bottle with tech1 in mind (aluminium, obviously). I can't see any particular requirements on the GUE site for tech1 and even tech2 only requires bottles of 30cu.ft or greater. Is there any reason to get a bottle larger than 40cu.ft.? Are there any other requirements I need to know other than material?

Get a 7L or CE marked AL80. For most T1 dives a 7L will be fine. For dives at the max T1 depths you may find that the limiting factor with a D12s+7L would be the deco gas, at which point you'll get a slightly longer dive with an AL80.

Chosing a 7L is a little more complicated than the 80. You either want the "old style" ie pre-approx 2002 or a new 207 bar rated one (which is the same as the old pre-2002 7L but with is stamped with a lower working pressure). The most commonly available 7s are "new" 232 bar cylinders which have thicker walls than the other two and are from memory a bit more than 1/2kg heavier as well as a little longer (due to the reduced internal diameter).

And get a silver one because they look best

David

May 13th, 2008, 01:37 PM	#5 (permalink)
David Martin(Offline) Instructor candidate Join Date: Jan 2006 Location: London, E11 Posts: 426	Quote: (Originally Posted by BarryNL) What would be the best choice for a stage bottle with tech1 in mind (aluminium, obviously). I can't see any particular requirements on the GUE site for tech1 and even tech2 only requires bottles of 30cu.ft or greater. Is there any reason to get a bottle larger than 40cu.ft.? Are there any other requirements I need to know other than material? Get a 7L or CE marked AL80. For most T1 dives a 7L will be fine. For dives at the max T1 depths you may find that the limiting factor with a D12s+7L would be the deco gas, at which point you'll get a slightly longer dive with an AL80. Chosing a 7L is a little more complicated than the 80. You either want the "old style" ie pre-approx 2002 or a new 207 bar rated one (which is the same as the old pre-2002 7L but with is stamped with a lower working pressure). The most commonly available 7s are "new" 232 bar cylinders which have thicker walls than the other two and are from memory a bit more than 1/2kg heavier as well as a little longer (due to the reduced internal diameter). And get a silver one because they look best David