Curious what people's thoughts are on LP27 (4L) bottles for onboard dil/O2? These would be mounted on a SG Defender with the travel/mini canister. SG generally recommends the 2L for the travel canister, but I don't see why the 4L bottles would be an issue (outside of just being fatter). Roughly the same height with similar buoyancy characteristics. Anyone diving them? Pros and cons?
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One of the "balances" to make is between scrubber capacity and gas capacity for a given dive or set of dives between changing the scrubber.
You certainly could use a 4L, but do you need that capacity? What would be the advantages of the extra weight, bulk, etc. There is also the problem of trying to find 4L bottles if / when you travel.
- brett
You certainly could use a 4L, but do you need that capacity? What would be the advantages of the extra weight, bulk, etc. There is also the problem of trying to find 4L bottles if / when you travel.
- brett
Cons, they are very large, heavy and about 4 dives worth of o2/dil
Pros, you can dive a whole weekend on them without refills
PS resale value is terrible, most people dislike the weight and bulk, 2 sets of 2L are far more versatile and you can bring different dils
Pros, you can dive a whole weekend on them without refills
PS resale value is terrible, most people dislike the weight and bulk, 2 sets of 2L are far more versatile and you can bring different dils
I guess my primary concern is the weight of the 4L vs. the 2L since the 4L is almost 2x the weight of the 2L (and that's only at the rated pressure, not cave filled). Based on the DGX spec sheet, the 4L is about 1.5 inches larger in diameter.
The biggest pro in my mind is the capacity (~34 cuft. at 3600 psi) vs. ~16 cuft. at 3600 psi for the 2L. The other pro would be the length of the tank, which is almost comparable to the 2L (with the travel/mini canister, not sure if the 3L would be ideal).
Ultimately, the 5.5lb scrubber is the limiting factor when thinking about time vs. capacity.
I can't speak to that unit, but I use LP27 for onboard o2 and dil on my optima.
It's extra gas without any extra real bulk. The unit is basically the same size either way, though it does make the unit a tiny bit taller, that's fine, it's still shorter than doubles.
The advantage is:
-More dives between fills
-Less need to be precise about the filled pressure, just check on a button gauge ahead of the dive and go
-More gas is always better in an emergency. Onboard dil is just inflation gas, but I can plumb either one into the loop or into a second stage for a bailout.
-For open water rec diving where I don't want to haul the big steel bailout tanks, I can more comfortably dive with smaller cylinders like al40's or al80's and use the onboard tank for dil too, so no switching the QC6 in saltwater.
I sold my al19's and bought another pair of the LP27's to have two of those instead. If I was traveling and needed to use an al19 again, no problem, the unit adapts to either tank without any tools (if you are ok with it being 2" taller than it really needs to be).
It's extra gas without any extra real bulk. The unit is basically the same size either way, though it does make the unit a tiny bit taller, that's fine, it's still shorter than doubles.
The advantage is:
-More dives between fills
-Less need to be precise about the filled pressure, just check on a button gauge ahead of the dive and go
-More gas is always better in an emergency. Onboard dil is just inflation gas, but I can plumb either one into the loop or into a second stage for a bailout.
-For open water rec diving where I don't want to haul the big steel bailout tanks, I can more comfortably dive with smaller cylinders like al40's or al80's and use the onboard tank for dil too, so no switching the QC6 in saltwater.
I sold my al19's and bought another pair of the LP27's to have two of those instead. If I was traveling and needed to use an al19 again, no problem, the unit adapts to either tank without any tools (if you are ok with it being 2" taller than it really needs to be).
Probably overkill in the interim, but long-term looking at using them for more extended range cave diving. But again, the scrubber will most likely be the limiting factor when we're talking 4+ hours in the water. But the idea of being able to do multiple dives without having to worry about fills is also nice.
The scrubber being above the dil/O2 bottles on the Optima is probably beneficial for using the 4L bottles vs. having the scrubber canister sitting between them adding more bulk. But a lot of people also configure their unit with onboard bailout such as LP50s so the form factor there is worse. I like the idea of having that extra capacity for either multiple dives, bigger dives, or just having more gas in an emergency.
broncobowsher
Contributor
Multiple dives on a single fill is the only positive I can think of.
Maybe a cave system with an extreme sawtooth profile?
Maybe a cave system with an extreme sawtooth profile?
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