Wish list

UWSojourner

What are the top features/options you'd like to see added to the Meg?


OK. I'll jump in (edited after smark alec response seen below) and put in a couple of wish list items.

1. More deco model options ( I think I heard that Bruce Shearwater was working toward this). I'd like to see a deep stop model (e.g. VPM-B, RGBM) with some ability to control conservatism.

2. Dive data recording with PC interface ( now I use my Suunto Vyper to store dive time/depth ). I think recording senosr PO2, selenoid firing data, beginning/ending cylinder pressures) would be cool. Don't know how you'd do it, but it would be fantastic to see diver generated additions of diluent and O2.

3. Not really Meg only related, but ... real CO2 detecting (not scrubber temp) would be great.

EBT

A halcyon badge?

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UWSojourner

Oops, need to clarify. These would be features to IMPROVE the Meg.

bgpartri

I'd like to clarify that the main reason for GF is to create deep stops. By adjusting the allowable supersaturation, it creates stops far deeper than the standard Buhlmann model.

Here is a dive with GF 100/100 which is Buhmann without the DSF (Depth Safety Factor)

The Drogon Dive Planner [v2:15]
========================================

Dive profile for default:
Step Depth SegT RunT Gas ppO2 END
================================================== =============
1 0.0-> 40.0 0:48 0:48 Nitrox 14 0.70 44
2 40.0-> 40.0 59:12 60:00 Nitrox 26 1.30 37

Deepest effective stop: 24m
Buhlmann + Gradient Factor decompression schedule:
Step Depth SegT RunT %MV Gas ppO2 END
================================================== =============
3 40.0-> 12.0 4:00 64:00 90.8 Nitrox 59 1.30 1
4 12.0-> 9.0 5:00 69:00 97.7 Nitrox 68 1.30 0
5 9.0-> 6.0 10:00 79:00 99.2 Nitrox 81 1.30 0
6 6.0-> 3.0 13:00 92:00 98.4 Oxygen 1.30 0
7 3.0-> 0.0 0:18 92:18 99.5
================================================== =============
Dive time: 1:00:00 Gradient Factors were used:
Ascent & Deco time: 0:32:18 Low factor: 100%
======== High factor: 100%
Total run time: 1:32:18

Ascent rate: 10, Descent rate: 50 (m/min) Total CNS: 51% OTUs: 136

CC Setpoints used:
Depth Setpoint CNS
==========================
* 50.9 CC CNS Total: 51%


Here is the same dive with GF 10/90:

The Drogon Dive Planner [v2:15]
========================================

Dive profile for default:
Step Depth SegT RunT Gas ppO2 END
================================================== =============
1 0.0-> 40.0 0:48 0:48 Nitrox 14 0.70 44
2 40.0-> 40.0 59:12 60:00 Nitrox 26 1.30 37

Deepest effective stop: 24m
Buhlmann + Gradient Factor decompression schedule:
Step Depth SegT RunT %MV Gas ppO2 END
================================================== =============
3 40.0-> 24.0 2:00 62:00 65.0 Nitrox 38 1.30 17
4 24.0-> 21.0 1:00 63:00 69.6 Nitrox 42 1.30 13
5 21.0-> 18.0 3:00 66:00 74.5 Nitrox 46 1.30 9
6 18.0-> 15.0 3:00 69:00 76.9 Nitrox 52 1.30 5
7 15.0-> 12.0 4:00 73:00 80.9 Nitrox 59 1.30 1
8 12.0-> 9.0 7:00 80:00 85.0 Nitrox 68 1.30 0
9 9.0-> 6.0 9:00 89:00 88.5 Nitrox 81 1.30 0
10 6.0-> 3.0 13:00 102:00 91.9 Oxygen 1.30 0
11 3.0-> 0.0 0:18 102:18 95.5
================================================== =============
Dive time: 1:00:00 Gradient Factors were used:
Ascent & Deco time: 0:42:18 Low factor: 10%
======== High factor: 90%
Total run time: 1:42:18

Ascent rate: 10, Descent rate: 50 (m/min) Total CNS: 56% OTUs: 150

CC Setpoints used:
Depth Setpoint CNS
==========================
* 56.5 CC CNS Total: 56%

There are a couple of things happening here. The first is that the dive plan is about 10 minutes longer. The second is that the stops are significantly deeper.

Bubble models may model decompression more accurately, particularly with long deep dives, but GF is a good tool for incorporating deep stops in Buhlmann profiles.

There is still a lot to learn about how to do dives to 100m+ but it seems clear that deeper stops and slower ascents are a good thing on all decompression dives.

Bruce Partridge
Shearwater Research Inc.

schford

Just to back up what bruce says a 10/90 GF very closely mirrors the RGBM profile on +1 conservatism I get with my Hs Explorer.

Both depth of stops and run times are very similiar. It is very complimentary - and if you want to change the conservatism on your Explorer then you can just tweak the GF to get a similiar profile to it.

Gap is a very useful tool to do this as you see the GF and RGBM dive plans on screen at the same time.

I guess if you have a VPM B computer (VR3 upgrade due out next month, saw one for real today! - thanks Phil) then you can do something very similiar so all in all I think GF is very versatile.

Stuart

bgpartri

I don't want to hijack the thread. Both here and at Innerspace people are thinking about new stuff.

I'm working on a minor software upgrade to add a couple of features and tune a couple of existing features, and I have been working on VPM for a while now.

At some point there is going to be new hardware too, so let fly with your wish list.

Ideas are always welcome.

I'd like an MP3 player so I can listen to a book on long decos.

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UWSojourner

Nothing against GFs. There is a difference, though, even if you start the deco at about the same depth. GFs tend to raise you through the intermediate depths faster and leave you at the shallower depths longer. But the real wish was for more options, without intending to say GFs were a poor option.

schford

well it really depends on what you set the GF at - but I find RGBM differentiates much more when you have helium in the mix compared to GF and really lengthens the shallow stops (much more than GF Buhlman)....

The more helium in the mix and the longer the dive the more you have to decrease the higher number in the GF to get a similiar profile and run time.

Although I agree the middle stops GF raises you faster.

Stuart

schford

Bruce - only wish list I can think of it to have 3 lines on the display so bottom line does not have to switch back and for between PPO2 and other info.

Stuart

Steve

My list in no particular order:

1. A lid similar to the one on the Classic KISS.

2. Counterlung dump similar to the one on the PRISM.

3. OC/CC DSV.

4. An option for back mounted counterlungs.

5. For it to magicly be lighter but still -ve.

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