80cu Tank at 800 Feet ????

[Tigerman]

Why go for technology when we can have waterheated speedos and an al80?

 

[Akimbo]

Okay, so now that y'all have figured out all these parameters . . . Just what would it take to dive to 800', suck down that AL80, and come back up?

Based on reasonable assumptions and the well established laws of physics and Murphy, I am figuring it is possible under ideal conditions with:

• A 1200 Lb droppable descent weight
• A 600 Lb positively buoyant syntactic foam module, preferably shaped like a Trident Missile
• A decompression chamber on the surface
• And a 300 PSI reserve — as long as you remain very very calm.

I didn't see where you specified how long you actually have to live after hitting the surface so I give it 90% probability of success. It might take a few test runs to iron out the kinks though.

 

[Jax]

Based on reasonable assumptions and the well established laws of physics and Murphy, I am figuring it is possible under ideal conditions with:

• A 1200 Lb droppable descent weight
• A 600 Lb positively buoyant syntactic foam module, preferably shaped like a Trident Missile
• A decompression chamber on the surface
• And a 300 PSI reserve — as long as you remain very very calm.

I didn't see where you specified how long you actually have to live after hitting the surface so I give it 90% probability of success. It might take a few test runs to iron out the kinks though.

OMG . . . you are so funny!

Really, I meant hanging stages and all that. And, of course, one would have to rule out a rebreather - that's cheating.

 

[ianr33]

Okay, so now that y'all have figured out all these parameters . . . Just what would it take to dive to 800', suck down that AL80, and come back up?

OMG . . . you are so funny!

Really, I meant hanging stages and all that. And, of course, one would have to rule out a rebreather - that's cheating.

Well if you want an actual schedule,and at the risk of teaching stupid deep diving on the internet,something like this.

Put 6/85 ( 6% Oxygen,85% Helium in the Al 80).Enough gas for a full minute at 800 feet and gets you back to 760 feet with 30 cu ft of gas to spare.

Probably not something to try at home though

The ICBD alerts can be ignored. The High CNS can be bypassed with Air Breaks. Dunno about the high OTUs

8 1/2 hour dive, over 1200 cu ft of gas. What could possibly go wrong ?

Conservatism = + 2

Dec to 200ft (3) Triox 21/35 60ft/min descent.
Dec to 500ft (8) Trimix 6/80 60ft/min descent.
Dec to 800ft (12) Trimix 6/80 80ft/min descent.
Level 800ft 1:55 (14) Trimix 6/85 1.51 ppO2, 62ft ead, 92ft end
Asc to 760ft (15) Trimix 6/85 -30ft/min ascent.
Asc to 610ft (20) Trimix 6/80 -30ft/min ascent.
Stop at 600ft 0:40 (21) Trimix 6/80 1.15 ppO2, 79ft ead, 94ft end
Stop at 590ft 1:00 (22) Trimix 6/80 1.13 ppO2, 77ft ead, 92ft end
Stop at 580ft 1:00 (23) Trimix 6/80 1.11 ppO2, 76ft ead, 90ft end
Stop at 570ft 1:00 (24) Trimix 6/80 1.09 ppO2, 74ft ead, 88ft end
Stop at 560ft 1:00 (25) Trimix 6/80 1.08 ppO2, 72ft ead, 86ft end
Stop at 550ft 1:00 (26) Trimix 6/80 1.06 ppO2, 70ft ead, 84ft end
Stop at 540ft 1:00 (27) Trimix 6/80 1.04 ppO2, 68ft ead, 82ft end
Stop at 530ft 1:00 (28) Trimix 6/80 1.02 ppO2, 67ft ead, 80ft end
Stop at 520ft 1:00 (29) Trimix 6/80 1.00 ppO2, 65ft ead, 78ft end
Stop at 510ft 1:00 (30) Trimix 6/80 0.99 ppO2, 63ft ead, 76ft end
Stop at 500ft 1:00 (31) Trimix 6/80 0.97 ppO2, 61ft ead, 74ft end
Stop at 490ft 1:00 (32) Trimix 6/80 0.95 ppO2, 60ft ead, 72ft end
Stop at 480ft 1:00 (33) Trimix 6/80 0.93 ppO2, 58ft ead, 70ft end
Stop at 470ft 1:00 (34) Trimix 6/80 0.91 ppO2, 56ft ead, 68ft end
Stop at 460ft 1:00 (35) Trimix 6/80 0.89 ppO2, 54ft ead, 66ft end
Stop at 450ft 1:00 (36) Trimix 6/80 0.88 ppO2, 53ft ead, 64ft end
Stop at 440ft 1:00 (37) Trimix 10/70 1.43 ppO2, 87ft ead, 109ft end <<< IBCD ppN2 alert <<<
Stop at 430ft 1:00 (38) Trimix 10/70 1.40 ppO2, 84ft ead, 106ft end
Stop at 420ft 1:00 (39) Trimix 10/70 1.37 ppO2, 82ft ead, 103ft end
Stop at 410ft 1:00 (40) Trimix 10/70 1.34 ppO2, 79ft ead, 100ft end
Stop at 400ft 1:00 (41) Trimix 10/70 1.31 ppO2, 77ft ead, 97ft end
Stop at 390ft 1:00 (42) Trimix 10/70 1.28 ppO2, 74ft ead, 94ft end
Stop at 380ft 1:00 (43) Trimix 10/70 1.25 ppO2, 72ft ead, 91ft end
Stop at 370ft 1:00 (44) Trimix 10/70 1.22 ppO2, 69ft ead, 88ft end
Stop at 360ft 1:00 (45) Trimix 10/70 1.19 ppO2, 66ft ead, 85ft end
Stop at 350ft 1:00 (46) Trimix 10/70 1.16 ppO2, 64ft ead, 82ft end
Stop at 340ft 2:00 (48) Trimix 10/70 1.13 ppO2, 61ft ead, 79ft end
Stop at 330ft 2:00 (50) Trimix 10/70 1.10 ppO2, 59ft ead, 76ft end
Stop at 320ft 2:00 (52) Trimix 10/70 1.07 ppO2, 56ft ead, 73ft end
Stop at 310ft 2:00 (54) Trimix 10/70 1.04 ppO2, 54ft ead, 70ft end
Stop at 300ft 2:00 (56) Trimix 14/50 1.41 ppO2, 119ft ead, 133ft end <<< IBCD ppN2 alert <<<
Stop at 290ft 1:00 (57) Trimix 14/50 1.37 ppO2, 114ft ead, 128ft end
Stop at 280ft 2:00 (59) Trimix 14/50 1.33 ppO2, 110ft ead, 123ft end
Stop at 270ft 2:00 (61) Trimix 14/50 1.28 ppO2, 105ft ead, 118ft end
Stop at 260ft 2:00 (63) Trimix 14/50 1.24 ppO2, 100ft ead, 113ft end
Stop at 250ft 2:00 (65) Trimix 14/50 1.20 ppO2, 96ft ead, 108ft end
Stop at 240ft 2:00 (67) Trimix 14/50 1.16 ppO2, 91ft ead, 103ft end
Stop at 230ft 3:00 (70) Trimix 14/50 1.11 ppO2, 87ft ead, 98ft end
Stop at 220ft 3:00 (73) Trimix 14/50 1.07 ppO2, 82ft ead, 93ft end
Stop at 210ft 4:00 (77) Trimix 14/50 1.03 ppO2, 78ft ead, 88ft end
Stop at 200ft 4:00 (81) Trimix 14/50 0.99 ppO2, 73ft ead, 83ft end
Stop at 190ft 3:00 (84) Triox 21/35 1.42 ppO2, 91ft ead, 112ft end
Stop at 180ft 3:00 (87) Triox 21/35 1.35 ppO2, 86ft ead, 105ft end
Stop at 170ft 5:00 (92) Triox 21/35 1.29 ppO2, 80ft ead, 99ft end
Stop at 160ft 5:00 (97) Triox 21/35 1.23 ppO2, 74ft ead, 92ft end
Stop at 150ft 5:00 (102) Triox 21/35 1.16 ppO2, 69ft ead, 86ft end
Stop at 140ft 6:00 (108) Triox 21/35 1.10 ppO2, 63ft ead, 79ft end
Stop at 130ft 7:00 (115) Triox 21/35 1.04 ppO2, 58ft ead, 73ft end
Stop at 120ft 9:00 (124) Triox 21/35 0.97 ppO2, 52ft ead, 66ft end
Stop at 110ft 9:00 (133) Triox 21/35 0.91 ppO2, 47ft ead, 60ft end
Stop at 100ft 11:00 (144) Triox 21/35 0.85 ppO2, 41ft ead, 53ft end
Stop at 90ft 15:00 (159) Triox 21/35 0.78 ppO2, 35ft ead, 47ft end
Stop at 80ft 17:00 (176) Triox 21/35 0.72 ppO2, 30ft ead, 40ft end
Stop at 70ft 14:00 (190) Nitrox 50 1.56 ppO2, 32ft ead <<< CNS high <<<
Stop at 60ft 19:00 (209) Nitrox 50 1.41 ppO2, 26ft ead <<< CNS high <<<
Stop at 50ft 26:00 (235) Nitrox 50 1.26 ppO2, 20ft ead <<< CNS high <<<
Stop at 40ft 37:00 (272) Nitrox 50 1.10 ppO2, 13ft ead <<< CNS high <<<
Stop at 30ft 54:00 (326) Nitrox 50 0.95 ppO2, 7ft ead <<< CNS high <<<
Stop at 20ft 67:00 (393) Oxygen 1.60 ppO2, 0ft ead <<< CNS high <<<
Stop at 10ft 112:00 (505) Oxygen 1.30 ppO2, 0ft ead <<< CNS high <<<
Surface (505) Oxygen -30ft/min ascent. <<< CNS high <<<

Off gassing starts at 672ft

OTU's this dive: 667 <<< OTU high <<<
CNS Total: 350.4% <<< CNS high <<<

308.0 cu ft Trimix 6/80
48.6 cu ft Trimix 6/85
129.2 cu ft Trimix 10/70
133.5 cu ft Trimix 14/50
266.8 cu ft Triox 21/35
208.2 cu ft Nitrox 50
152.0 cu ft Oxygen
1246.2 cu ft TOTAL

 

[Jax]

Well if you want an actual schedule,and at the risk of teaching stupid deep diving on the internet,something like this.

<snipped>

Holy smokes! That's a lot of stops and bottles! Thanks!

Oh, and don't worry about the other . . . it's called Darwinism . . .

 

[Akimbo]

Holy smokes! That's a lot of stops and bottles! Thanks!

Oh, and don't worry about the other . . . it's called Darwinism . . .

I wasn't joking about the Six-Packs and tube trucks part.

… Keep in mind you're discussing this with a guy who thinks of gas supplies in terms of six-packs and tube trailers.

http://www.scubaboard.com/forums/te...ties/337376-use-heliox-commercial-divers.html
....

 

[Jax]

I wasn't joking about the Six-Packs and tube trucks part.

But that was with your SPG blown up, right?

:kiss2:

 

[Akimbo]

But that was with your SPG blown up, right?

:kiss2:

No problems with this one ... yet. A little heavy though.

 

[Jax]

No problems with this one ... yet. A little heavy though.

Wow, that's some serious chunk of stainless steel there! How long do you stay down when you go?

 

[Akimbo]

Wow, that's some serious chunk of stainless steel there! How long do you stay down when you go?

Serious, this gauge gets bolted outside the bell so you can see it through one of the view ports. Some certifying agencies, and diving companies as policy, don't allow HP gas inside the bell except for bail-out bottles. Industrial gas bottles are wrapped outside the bell for normal oxygen make-up inside the bell atmosphere and emergency pre-mixed HeO2 in case the surface supply fails -- like a blown hose or cut umbilical. That way, some hundreds to thousands of cubic feet of gas is available to get the dive(s) back into the bell without having to resort to the puny +/-80 Ft³ of gas in their bail-outs.

Remote-sensing pressure reducing regulators are also outside so only LP gas enters the bell (150-300 PSI). There was no other way to monitor pressure in the onboard banks. We used different gauges in the same housing for the 6000 PSI banks on deeper bells.

Is this making sense or way more than anyone wants to know?