Shearwater Petrel EXT, Operation Manual, Page: 25 / 65

Shearwater Petrel
Revision 1.1.0 25 Shearwater Research Inc.
Complex Example Dive
This is an example of the displays that might be seen on a dive� This example shows a
complicated dive with multiple Closed Circuit (CC) gases and multiple Open Circuit (OC) bail-
out gases� A normal, single gas CC or OC dive wouldn’t have any button pushes at all, so
there isn’t much to show�
The first step is to calibrate. Since we are on the surface and not diving, MENU will bring up
“Turn Off”, then “Calibrate.” Once the loop is flushed with oxygen, SELECT will bring up the
confirmation display, and another SELECT will calibrate.
Next, we check the closed circuit diluent gases that we have programmed� Entering the gas
selection function by pressing SELECT with the “Select Gas” menu item showing will display
the first CC gas that is available. MENU will increment to the next gas available. Another
MENU takes us back to the “Select Gas” menu item. Those are the only two gases configured.
We SELECT gas number 2, the Trimix 10/50�
The system will use both of these gases for our dive when calculating the TTS� It assumes a
diluent switch at a PPO2 of 1�05� That means that it will assume that you have switched to an
air diluent at 124 feet� This is only for the TTS prediction� The computer will always use the
currently selected gas for tissue loading calculations�
Then we switch to open circuit to look at our bail-out gases� Flipping through the gases with
MENU shows that we have three gases available� (Whether they are appropriate gases is a
subject for one of the web forums�)
DEPTH TIME SURFACE
O
Calibrate
.85 .86 .84
DEPTH TIME SURFACE
O
CC 21/OO O O
.98 .98 .98
O2/HE NDL TTS
DEPTH TIME STOP TIME
O
Select Gas
.98 .98 .98
Cal. milliVolts
Cancel Calibrate
45.1 46.3 44.O
Cal. @ FO2= .98
.85 .86 .84
DEPTH TIME STOP TIME
DEPTH TIME STOP TIME DEPTH TIME STOP TIME
DEPTH TIME STOP TIME
DEPTH TIME STOP TIME
Next Gas
Next Gas Next Gas
Cancel
Cancel
Select
Select Select
Select
Select
O
O O
O
O
Set A1 CC 21/OO
Set 2 OC 5O/2O Set A1 OC 99/OO
Set 2 CC 1O/5O
Set 3 OC 14/55
.98 .98 .98
.98 .98 .98 .98 .98 .98
.98 .98 .98
.98 .98 .98