Which Profile is More Conservative

Which Profile is More Conservative?

  • Profile 1

    Votes: 0 0.0%

  • Profile 2

    Votes: 3 100.0%
  • Total voters
    3

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Michael Guerrero

Michael Guerrero

Contributor
Messages
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Location
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Which profile is more conservative? This is an air dive to 150' for 30 minutes w/ EAN80 deco gas:

Profile 1:
================================================== =======
DESC:150ft for 02:16 [ 2] on Air, SP: 0.0, END:150ft
DIVE:150ft for 27:43 [ 30] on Air, SP: 0.0, END:150ft
ASC : 40ft for 03:20 [ 33] on Air, SP: 0.0, END: 40ft
DECO: 40ft for 03:57 [ 37] on Air, SP: 0.0, END: 40ft M-Value: 90% [03],
DECO: 30ft for 04:17 [ 42] on Nitrox 80, SP: 0.0, END: 0ft M-Value: 92% [04],
DECO: 20ft for 06:05 [ 48] on Nitrox 80, SP: 0.0, END: 0ft M-Value: 91% [04],
DECO: 10ft for 12:23 [ 60] on Nitrox 80, SP: 0.0, END: 0ft M-Value: 91% [05],


Profile 2:
================================================== =======
DESC:150ft for 02:16 [ 2] on Air, SP: 0.0, END:150ft
DIVE:150ft for 27:43 [ 30] on Air, SP: 0.0, END:150ft
ASC : 40ft for 03:20 [ 33] on Air, SP: 0.0, END: 40ft
DECO: 40ft for 04:39 [ 38] on Air, SP: 0.0, END: 40ft M-Value: 90% [03],
DECO: 30ft for 04:41 [ 43] on Nitrox 80, SP: 0.0, END: 0ft M-Value: 91% [04],
DECO: 20ft for 07:05 [ 50] on Nitrox 80, SP: 0.0, END: 0ft M-Value: 89% [04],
DECO: 10ft for 15:05 [ 65] on Nitrox 80, SP: 0.0, END: 0ft M-Value: 89% [05],
 
My vote is none. For me this dive would be done on 25/20, with 70%. Are you confused yet?
Eric
 
21/35 with 50% here. VPM with +3 conservatism gives a 65 minute run time.
 
I'll be curious to hear what you're thinking is the relevant distinction, because there are just not enough high PP inert gas stops for me to think that #1 has an edge on #2. The only point at which I'd question the value of #2 over #1 is at the 40' stop on air, and the less than 1 extra minute #2 has isn't enough to change the fact that it's giving you a lot more time on a very low N2 deco gas.

Now, run a VPM-B 0 schedule for the same dive and you'd have a rather different question as to what the more conservative approach is:

[TABLE="width: 500"]
[TR]
[TD]Depth[/TD]
[TD]Stop[/TD]
[TD]Run[/TD]
[TD]Mix[/TD]
[/TR]
[TR]
[TD]DEC 150'[/TD]
[TD]-[/TD]
[TD]2[/TD]
[TD]21%[/TD]
[/TR]
[TR]
[TD]150'[/TD]
[TD]27[/TD]
[TD]30[/TD]
[TD]21%[/TD]
[/TR]
[TR]
[TD]ASC 80'[/TD]
[TD]-[/TD]
[TD]32[/TD]
[TD]21%[/TD]
[/TR]
[TR]
[TD]80'[/TD]
[TD]1[/TD]
[TD]33[/TD]
[TD]21%[/TD]
[/TR]
[TR]
[TD]70'[/TD]
[TD]1[/TD]
[TD]34[/TD]
[TD]21%[/TD]
[/TR]
[TR]
[TD]60'[/TD]
[TD]3[/TD]
[TD]37[/TD]
[TD]21%[/TD]
[/TR]
[TR]
[TD]50'[/TD]
[TD]4[/TD]
[TD]41[/TD]
[TD]21%[/TD]
[/TR]
[TR]
[TD]40'[/TD]
[TD]6[/TD]
[TD]47[/TD]
[TD]21%[/TD]
[/TR]
[TR]
[TD]30'[/TD]
[TD]4[/TD]
[TD]51[/TD]
[TD]80%[/TD]
[/TR]
[TR]
[TD]20'[/TD]
[TD]6[/TD]
[TD]57[/TD]
[TD]80%[/TD]
[/TR]
[TR]
[TD]10'[/TD]
[TD]10[/TD]
[TD]67[/TD]
[TD]80%[/TD]
[/TR]
[/TABLE]
 
I have probably a couple hundred dives with similar profiles except for the 80%. I prefer 50% beginning at 70 feet and 100% at 20 feet. Why did you choose 80%?
 
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