CCR Testing

Paul Sargent paul.lionseye at
Tue Oct 28 07:00:17 PDT 2014

I've been spending a bit of time this morning playing with CCR Dives
on the latest git version (ee7c86f206f5465df0f0ade08b13da3b8062e67f).
This is quite a long mail, but just trying to get everything down.

Dive Logs

I dive with two computers on all my CCR dives. There's a Shearwater
Predator on the unit which monitors the cells, and I use an OSTC 2C as
a backup in fixed ppO2 mode.

Looking at old dives I think most of my problems at the moment are
really around importing.

  - Importing from Shearwater Desktop via XML, all my dives are air dives.
  - Importing from Shearwater Desktop via CSV isn't configurable enough.
  - Old logs imported from my OSTC into Subsurface 3.x and brought
    forward have gas change events in them, but limited information
    about gasses. Only really matters when I've done OC ascents from a
    CCR dive (Called 'Bailing out', done in emergencies and training).

Loading up one of my old OSTC CCR training dives that included
bailouts, the log knew that the switch had taken place (placed an
icon), and seemed to calculate deco correctly, but it seemed to think
I'd switched to the same gas. This was until I added the gas manually
to the dive, and then it associated correctly. Neither the deco or the
O2,N2,He graphs changed with the addition of gasses. It also seems
that what it's done is take the changes as diluent switches, and
stayed on CC. I say this because the ppO2 is fixed throught all the
gas switches.

I've yet to try importing from the computers themselves, will try and
report back. I think I can only get the bailout dive from my OSTC
though. I wasn't diving my Shearwater (although I do have the computer
dump files that Shearwater desktop saves)

Dive Planning

I've noticed is that if I plan a dive and include bailout gasses, then
it'll switch to them during ascent, but not off CCR (ppO2 is still
fixed). I have to delete the gasses to avoid it doing this.

Inserting a extra dive segment with a Setpoint of 0.0, causes a gas
switch to the bailout gas, and a bailout warning triangle, but the
ppO2 graph stays fixed at the original setpoint, which suggests things
aren't right.

For CCR planning I'd say we to either have a button to switch between
CC and OC ascent, or be able to see both together. Both are important,
and you need to be able to play with the plan whilst refering to
both. Having them as two separate dives is a pain.

For fun I put a plan in that is well beyond me, but some of my friends
have done.

have done.

  - Descent rate 20m/min
  - All ascent rates 10m/min
  - Drop to first depth checked.
  - 130m - duration 11m
  - GF 30/85
  - Setpoint 1.3
  - One gas - 10/70

The graph turns red because the first stop is above the ceiling. This
didn't seem to happen with 4.2.

Doing my standard 30m at 70 metres diving 1.3ppO2 on 16/40 no bailout
plan, I've noticed that the plan has become slightly shorter (113 mins
instead of 121 mins in 4.2). This brings it more in line with other


Honestly, for me, I'm not sure what's really changed since 4.2. I know
there are changes, but pretty much everything I've done I could do
with 4.2. There are a couple of exceptions.

  - Tissue Graph: I like.
  - Tank Bar: Really like, but for me would be really useful if it
    distinguished between OC & CC too.

In general the behaviour is the same as 4.2 (apart from the
deco). Maybe once I can actually get ppO2 data imported then I might
notice a difference.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 495 bytes
Desc: Message signed with OpenPGP using GPGMail
URL: <>

More information about the subsurface mailing list