Stage bottle question.

[battles2a5]

I can dive that deep usually on a single 80 and barely escape going into deco. thats also before violating thirds. If its a current dive or bad viz or in a strange place maybe my gas consumption would require additional tanks but doubtful. I would just dive the 72's, of course if you only have 1 set of 72's than I would dive the 80 dry like everyone said just watch the buoyancy.

I don't think bouyancy will be an issue when he still has a set of full still doubles on his back at the end of the dive

 

[Rick Inman]

Well the biggest point in favour of 2 forties for me, is that I have tons of dives slinging a 40, but only 1 or 2 slinging an 80.

Another good reason to sling the 80. Get more dives/practice with the 80.

Well that's the kicker, I only have the one set of doubles right now.

A whip can help wth that in the mean time if you don't want to sling.

 

[Doppler]

Well that's the kicker, I only have the one set of doubles right now. When I had my double 108's with a slight overfill, I could easily do both these dives, but the 72's are cutting it way too close for my liking, especially when factoring in emergency gas for my buddy.

Logistically breathing the 80 on dive one and using the doubles for dive #2 makes sense. The usable gas for the first dive is only what's in the single (therefore you would turn the dive after consuming about 40 cubic feet, 1500 psi and aim to do your SS on the seeds and stems from that cylinder). However, speaking of your buddy, what is his/her plan? Your gas management plans should be the same or at least be controlled by whomever starts with the least volume... I see no mention of this in your posts or those of any respondents.

 

[Jimmer]

Very good point about my buddy's gas plan. He'll be diving an hp100, and slinging a 40 for emergency only and not part of his gas plan. Now he's an air hog, and I would expect the 80 to last as long, if not a touch more than his 100 anyway, so odds are good that the 80 wont be empty when we're finishing the dive now that I think about it.

I'm learning more and more about gas management all the time.

Logistically breathing the 80 on dive one and using the doubles for dive #2 makes sense. The usable gas for the first dive is only what's in the single (therefore you would turn the dive after consuming about 40 cubic feet, 1500 psi and aim to do your SS on the seeds and stems from that cylinder). However, speaking of your buddy, what is his/her plan? Your gas management plans should be the same or at least be controlled by whomever starts with the least volume... I see no mention of this in your posts or those of any respondents.

 

[Flightlead]

Take the 80 and use all the gas in it on the first dive. Then just ue back gas on the second dive.

my thoughts also.

slinging an 80 s/b fine in the water if the bottle and your harness is adjusted correctly. it will just find its own place and you will forget about it. breath it first all the way down. when you are done breathing it, you can clip the top clip to your hip d-ring and it will really be out of the way. like its not there. when I have one clipped off there that is really empty I sometimes feel a bit lopsided when I'm hanging (but not swimming) due to the slight buoyancy of the empty 80, its easy to manage though. you will only need to carry it on one dive.

you have plenty of redundancy in your doubles...assuming you know how to manage them of course if there is an emergency situation, you s/b able to ditch the stage (assuming its not required for deco), so breath it first. that maximizes your remaining gas should you have to ditch it. unless you need to have multiple gasses, e.g. for accelerated deco, why futz with the added complexity etc of two 40's?

 

[texdiveguy]

I far prefer 80's for traveling stages and for deco bottles.

In the case of the OP use a slung 80 and breath it down to a safe limit on your first dive conserving your back gas 72's,,,,,I have followed similar planning on dives in the past and it works well.

Gas management is one of your prime objectives for pre-dive planning with your buddy.....have fun and be safe!

 

[Jimmer]

Well I took the advice here and dove an 80 stage on the first dive and it worked great. Easily balanced, tons of gas and I only ended up using 2000psi out of it, and the rest of the dive went perfectly to plan. I think I'll definetly be using this practice on more of my deeper dives from now on. The one thing I did take notice of this time, was just making sure my inflator hose was on top of the stage and not trapped under the bottle or stage rigging, which has never seemed to be an issue when I sling 40's.