Different Deco Time to other ZH-L16/C planners

[Tom HE]

Hi! I received my new OSTC 2N today and I think its a great piece of kit. However I've been playing with the simulator and decoplanning option and whatever setting I seem to use the OSTC and OSTC Planner software seem to give much longer deco times than other software on the same algorithm. Is there some setting I've missed?

The Gradient factors in all the software are 30/90 and the plans they produce for 31min at 42m on air (not a dive I plan on doing but usable as an example) are as follows...

OSTC2N
21m = 1'
18m = 2'
15m = 3'
12m = 5'
9m = 7'
6m = 67'
Total = 85 Min Deco

OSTC Planner
21m = 1'
18m = 2'
15m = 3'
12m = 4'
9m = 7'
6m = 64'
Total = 81 Min Deco

iDeco
21m = 1'
18m = 1'
15m = 1'
12m = 3'
9m = 5'
6m = 36'
Total = 47 Min Deco

MV-Plan (might be ZH-L16/B)
21m = 1'
18m = 1'
15m = 2'
12m = 4'
9m = 6'
6m = 38'
Total = 52 Min Deco

The 38 min difference between iDeco and my OSTC2N for the same algorithm and GFs seems a bit much and all CFs are at default (apart from 6m last stop). Anyone got any idea what I'm missing here?

Thanks!

Tom

[Chilihead]

maybe different air pressure ... sealevel or high altitude... but 38min...

[scubatinoo]

I'm getting in OSTC-Planner (latest version 314) a plan like this:
21 m : 1 ' 34 '
18 m : 1 ' 36 '
15 m : 3 ' 39 '
12 m : 4 ' 43 '
9 m : 6 ' 49 '
6 m : 50 ' 100 '
0 m : --- ' 101 '

And in Vplanner
Stop 21m 1:00 (35)
Stop 18m 3:00 (38)
Stop 15m 3:00 (41)
Stop 12m 6:00 (47)
Stop 9m 8:00 (55)
Stop 6m 49:00 (104)

So what is right and what is wrong...?

[Bardass]

tom, check your settings, I have almost the same run-time with ostc, ostc planner, MV-Plan and Gap

[dmainou]

Search the posts...

It all comes down to the settings of the computer AND the software you are using.

Deco offset is one of those things to look for.

[Tom HE]

Thanks for all the replies. Changing the deco offset to 0 brought the last stop to ~56min rather than 67min but I don't think my stops are quite that good yet! I'll keep playing around before I take it diving and let you know if I find where I've been going wrong

Tom

[dmainou]

There's lots of things that can affect it.

Starting with the current pressure. I currently have 1008mb and got a run time of 75) with GF 30/85 and last at 3m
The fact that the simulator has instant travel to the bottom (i.e. you start already there)where some of those simulators assume you start on the surface and then spend some bottom time going down. Between 2.5 and 5 minutes at with your simulation.
The ascent speed for simulation 7m/min
The fact that your last stop is at 6m on AIR (highly inefficient)

Keep trying you'll get there. Then go back to the defaults... most of them are niceties others are there for a reason.

D

[Bardass]

It's not possible to set ascent speed on OSTC, always at 10m/min
You can only set display (CF05) and warning (CF47) for ascent speed

With OSTC Planner, you can change ascent speed
That don't modify stops, only time to ascent

[Tom HE]

Well I played a lot with all the settings I could find and couldn't get a match but I tried GAP and I matches almost perfectly without any modifications so I'm fairly happy now that there is something I'm missing in the other software I'm comparing too and not the OSTC (although I'm still going to try and find the cause of the differences).

I plan on diving on pretty much default settings for the OSTC until I really get to grips with it and then maybe modifying some GFs if/when I start diving much deeper.

Thanks for the replies everyone!

Tom

*Edit = Turned out to all be down to how the different programs handled runtime and descent times and the deco offset CF. I should have just looked harder! Got everything working within a few minutes of each other now.