|Departure's Dive Planning and Decompression Software|
Note and Warning: The following decompression examples and decompression screen shots are based upon other data entered into the Departure decompression software program and uses decompression gasses that are not shown. They are presented as an example only. More conservatism settings are desirable and should be followed.
The following is an abbreviated tour of the screens and decompression possibilities of Departure. Not all the features will be discussed. This is just a quick overview of Departure.
The first page is where you enter how you want to model your decompression stops and ascent as well as what units of measurements you will use. You may use the sliding scale to scroll and pick you time limits and level of decompression conservatism, or you may customize your time limits (shown in the next screen).
Below shows the option of customizing your no-stop time limits instead of using the scroll bar shown above.
The next step is to enter the way you will measure your depth as well as the altitude you are diving at and the altitude, if any, to which you will be ascending after the dive. The example below shows a common dive that is performed at Lake Tahoe, where the divers come from Reno (altitude of 4412 ft.), wait 3 hours upon arrival before diving at Tahoe (altitude 6229 ft.) and then have to drive over a small pass (altitude 7150 ft.) to leave Tahoe. The diver can also specify whether they pre-breathed a nitrox mix (in this example oxygen for 30 minutes) to help equalize their tissues upon arrival at altitude in addition to the normal surface interval.
After entering your altitude information (which is automatically saved for the next time you use Departure), enter information on your gas consumption and other information (which is also automatically saved).
The next step is to enter any decompression gasses that will be used during the dive. You may enter the exact mixture you are using as well as the depth you want to switch at.
or for those of you using a rebreather, just use your deco diluent gas (or multiple diluent deco gasses including trimixes) and Departure will calculate your decompression stops at the fixed partial pressure of oxygen you desire.
Now to the last screen. This is where you will input the information on your dive. You can let Departure calculate the mix you desire based upon the partial pressures of Oxygen and Nitrogen you prefer. You can also change this mix if desired. Here is where you enter the depth and time of the dive as well as descent and ascent rates. You can also pick the ceiling you desire for your final stop. In this example a ceiling of 13 feet was chosen simply to show that it need not be 10, 15 or 20 feet. You can also increase the depth of your first stop. In this example it was increased by 20 feet. Your decompression profile is now generated which shows the depth of the stops, the time at the stop as well as the Oxygen percentage you have accumulated. This screen cal also show running stop time or actual run time (shown below) if desired. At the bottom right of the screen, information is given on the amount of gas that will be needed to do the dive. Notice that three decompression gasses (in addition to the bottom gas) are being used in this example.
This shows the same screen as above with the exception of the decompression stops being shown with a total run time.
There is naturally a rebreather option too.
Departure also lets you add decompression time to a stop if desired. In the below examples, a minimum time of 5 minutes is desired at 70 feet. This recalculates the shallower stops.
On deeper dives, the decompression ascent or curve can also be adjusted by adding times to the stops to generated a more uniform curve if desired. For example on a dive to 300 for 15 minutes generates a 2 minute stop at 150 feet and then 1 minute stop at 140 feet, followed by a 3 minute stop at 130 feet, and then 1 minute stops starting at 120 feet (due to a gas switch at 120 feet) as shown below. Also notice that the final decompression depth was reduced to 10 feet which causes more decompression time to occur at 20 feet, thus taking into account that being under more pressure at 20 feet to reduce nuclei and bubble growth is more efficient for gas elimination.
The 140 foot stop can be adjusted if desired to also be 2 minutes just as the 150 stop. This automatically reduces the 130 foot stop to 2 minutes. Now the 120 foot and shallower stops can also be increased to 2 minutes. This makes each shallower depth have the same or longer stop time than the previous depth. Notice this only changes the overall decompression time by 2 minutes.