DDPLAN

The Drogon Dive Planner

Copyright © 1999 - 2001 Gordon Henderson

What's new in this release...

Version 2.15, June 1st 2001:

Version 2.15 fixes various minor bugs and introduces some new features. It's designed to be a preliminary release prior to a release which supports the VPM decompression model.

Bugs/Features fixed:

  • There was a bug in table generation whereby the gas column wasn't printed unless the end-time in the table is an exact multiple of the time interval.

  • If you selected a gas-set for use as a diluent in closed circuit mode and it included 100% Oxygen then strange and incorrect results would be shown in the run screen. This has been fixed. Note however that specifying more than one diluent flush on the ascent isn't really a sensible thing to do.
  • Some minor text formatting problems in the edit screen have been fixed.

Features added:

  • A lot more checks are now performed to validate the profile in the editor before a table is generated.

  • CNS and OTU calculations and display. The CNS and OTU is calculated for each stage of your dive as well as the sum total. It also introduces CNS, OTU and gas consumption calculations, as well as giving an indication of the deepest possible stop for the given profile.

    The calculations for closed circuit ascending and descending have also been re-written to be more accurate and much faster than the iterative method used in DDPLAN 2.10 and earlier. The side-effect of this is that closed circuit profiles will generally be a few minutes shorter in duration than before, depending on the depth and duration of the profile. (The deeper and longer the profile, the more minutes shorter the profile may be) Open Circuit calculations are unaffected. If you are not happy with these slightly shortened profiles then there are 2 things you can do. You could lower the Gradient factor high by a couple of points, or you can start DDPLAN with a -210 parameter. This forces it to calculate everything using the same code as in versions 2.10 and earlier.

    Eg:     C:\DDPLAN.215\> DDPLAN -210

  • Documentation updates.

Version 2.10, 1st October 2000:

This version of DDPLAN now supports automatic table generation. Apart from a minor menu correction, there have been no other changes to the operation of the software.

Version 2.05, 7th May 2000:

Thanks to people actually using it and doing things with it that I didn't really consider, two implementation bugs have come to light since version 2.00. They are unlikely to bend you (any more than the current software is capable of bending you), but one of them can add a few moments more to a dive profile than strictly necessary.

One of the bugs manifested itself in the duration of the very first decompression stop - making it a lot longer than it strictly needed to be. The other stops were unaffected (but might have been longer (or shorter!) to take into consideration possible tissue on-loading (or off-loading) while on the "extended" first stop. Oddly enough, it showed up more on shallower, shorter air dives than deeper and longer dives on Trimix. Eg an OC air dive to 36m for 25 minutes showed the ascent and first stop at 18m (with a GF Low of 20) to be for a duration of 6 minutes instead of 2.

The reason for this bug was my placement of the calculation of the next gradient factor - I was calculating it at the point where you leave the stop - so the stop duration was calculated with the current (first) gradient factor, hence the ceiling was taking a long time to rise to the next 3m depth. Doing the calculation for the next GF immediately after arriving at the stop depth has solved the problem. (and is, I believe the correct place to put it)

I've done a few dives with it recently with this big fix implemented, and one thing I've found is that I'm obviously crap at doing ascents on a delayed SMB line! On the 2 30m dives I did over the May Spring bank holiday weekend, DDPLAN gave me 2 minutes to get from 30m to 12m and I found I was taking at least 3 minutes to do that ascent!

So - 2 ways round this, either I improve my ascent technique, or add in a fudge factor to DDPLAN which will deliberately extend the first stop... I've initially opted for the latter solution, but will work on improving my own ascent technique... (Shot-line ascents have been OK for me so far, maybe I ought to get a better reel!)

The 2nd bug shows up when you have intermediate stops enabled and you do a deep gas switch - eg. bailing out on a rebreather dive to OC. DDPLAN will then do a stop every 3m from that gas switch depth which isn't necessarily what you want!

I've also included a few minor formatting fixes and so on, as well as using 2 setpoints for CC use so that in the editor it makes it easier to add the lines for a CCRB dive.

It's important to install this version in a new directory and not on top of the old one - the settings file has had additions and I've renamed the gases file in the data directory (from gases to gases after someone whinged about my spelling!

Version 2.00, December 19th, 1999. Initial release

DDPLAN released to the public at large!

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