Shearwater Petrel 3 User manual

Recreational Modes
Operating Instructions

Page 2 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
Table of Contents
Table of Contents��������������������������������������������������������������� 2
Conventions Used in this Manual����������������������������������������������������� 3
1. Introduction ................................................. 4
1�1� Notes on this manual������������������������������������������������������������������� 5
1�2� Modes Covered by this Manual������������������������������������������������ 5
1�3� Models Covered by this Manual����������������������������������������������� 5
2. Basic Operation ........................................... 6
2�1� Turning On ��������������������������������������������������������������������������������������� 6
1�4� Customizable Splash Screen ���������������������������������������������������� 6
2�2� Buttons�����������������������������������������������������������������������������������������������7
2�3� Changing between Modes��������������������������������������������������������� 8
3. Dive Interface............................................... 9
3�1� Default Dive Setup������������������������������������������������������������������������ 9
3�2� Dive Mode Differentiation���������������������������������������������������������� 9
3�3� Main Screen������������������������������������������������������������������������������������10
3�4� Detailed Descriptions ������������������������������������������������������������������ 11
3�5� Mini Displays ����������������������������������������������������������������������������������14
3�6� Info Screens������������������������������������������������������������������������������������ 15
3�7� Info Screen Descriptions �����������������������������������������������������������16
3�8� Notifications����������������������������������������������������������������������������������� 21
3�9� Customizable Alerts������������������������������������������������������������������� 23
3�10�List of primary notifications����������������������������������������������������24
4. Safety and Decompression Stops .......... 26
4�1� Safety Stops����������������������������������������������������������������������������������26
4�2� Decompression Stops ��������������������������������������������������������������� 27
5. Decompression and Gradient Factors ... 28
5�1� Decompression Information Accuracy �������������������������������29
6. Example Dives ........................................... 30
6�1� Single Gas Example Dive ���������������������������������������������������������30
6�2� Multi-Gas Example Dive�������������������������������������������������������������31
7. Gauge Mode ............................................... 33
8. Compass ..................................................... 34
9. Air Integration (AI) ................................... 35
9�1� What is AI? ������������������������������������������������������������������������������������35
9�2� Basic AI Setup ������������������������������������������������������������������������������36
9�3� AI Displays �������������������������������������������������������������������������������������39
9�4� Sidemount AI���������������������������������������������������������������������������������41
9�5� Using Multiple Transmitters�����������������������������������������������������42
9�6� SAC calculations��������������������������������������������������������������������������43
9�7� GTR calculations��������������������������������������������������������������������������44
9�8� Transmitter Connection Issues�����������������������������������������������45
10. Menus .......................................................... 46
10�1� Menu Structure ����������������������������������������������������������������������������46
10�2�Turn off��������������������������������������������������������������������������������������������47
10�3�Select Gas (3 GasNx only)�������������������������������������������������������47
10�4�Dive Setup �������������������������������������������������������������������������������������48
10�5�Dive Log�������������������������������������������������������������������������������������������51
11. System Setup Reference.......................... 52
11�1� Mode Setup ����������������������������������������������������������������������������������� 53
11�2� Deco Setup������������������������������������������������������������������������������������54
11�3� AI Setup������������������������������������������������������������������������������������������ 55
11�4� Bottom Row ���������������������������������������������������������������������������������� 57
11�5� Nitrox Gases���������������������������������������������������������������������������������� 57
11�6� Alerts Setup ���������������������������������������������������������������������������������� 57
11�7� Display Setup��������������������������������������������������������������������������������58
11�8� Compass�����������������������������������������������������������������������������������������58
11�9� System Setup��������������������������������������������������������������������������������59
11�10�Advanced Config ����������������������������������������������������������������������� 60
12. Firmware Update and Log Download .... 62
12�1� Shearwater Cloud Desktop �����������������������������������������������������62
12�2� Shearwater Cloud Mobile���������������������������������������������������������64
13. Changing the Battery ............................... 65
13�1� Behavior on Battery Change ��������������������������������������������������66
14. Storage and Maintenance ........................ 67
15. Servicing..................................................... 67
16. Glossary ...................................................... 67
17. Petrel 3 Specifications ............................. 68
18. Regulatory Information............................ 68
19. Contact ....................................................... 69

Page 3 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
Conventions Used in this Manual
These conventions are used to highlight important
information:
INFORMATION
Information boxes contain useful tips for
getting the most out of your Petrel 3�
CAUTION
Caution boxes contain important instructions
for operating your dive computer�
WARNING
Warning boxes contain critical information
that may affect your personal safety�
This computer has bugs. Although we haven’t found them all yet,
they are there. It is certain that there are things that this computer
does that either we didn’t think about or planned for it to do
something different. Never risk your life on only one source of
information. Use a second computer or tables. If you choose to
make riskier dives, obtain the proper training and work up to them
slowly to gain experience.
This computer will fail. It is not whether it will fail but when it will
fail. Do not depend on it. Always have a plan for how to handle
failures. Automatic systems are no substitute for knowledge and
training.
No technology will keep you alive. Knowledge, skill, and practiced
procedures are your best defense (except for not doing the dive, of
course).
WARNING
This computer is capable of calculating decompression stop
requirements. These calculations are at best a guess of real physiological
decompression requirements. Dives requiring staged decompression
are substantially riskier than dives that stay well within no-stop limits.
Diving with rebreathers and/or diving mixed gases and/or performing
staged decompression dives and/or diving in overhead environments
greatly increases the risk associated with scuba diving.
YOU REALLY ARE RISKING YOUR LIFE
WITH THIS ACTIVITY.
DANGER

Page 4 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
Features
• High-contrast 2�6” AOLED display
• Rugged computer construction
• Titanium bezel
• User replaceable battery
• Powerful vibration alerts
• Programmable depth sampling rates
• Depth sensor calibrated to 130 msw
• Depth sensor function past 300 msw
• Crush pressure rating of 290 msw
• 5 customizable gases in technical diving modes
• Any combination of Oxygen, Nitrogen and Helium
(Air, Nitrox,Trimix)
• Full decompression and CCR Support
• External PPO2 monitoring of 1, 2 or 3 ocxygen
cells (Ext� Models Only)
• Bailout rebreather mode (Ext� Models Only)
• Bühlmann ZHL-16C with gradient factors standard
• Optional VPM-B and DCIEM decompression
models
• No lockout for violating deco stops
• CNS Tracking
• Gas Density Tracking
• Quick NDL and full decompression planner built in
• Simultaneous wireless pressure monitoring of up
to 4 cylinders
• Sidemount diving features
• Tilt compensated digital compass with multiple
display options
• Bluetooth Dive log uploading to Shearwater Cloud
• Free firmware updates
1. Introduction
The Shearwater Petrel 3 is a dive computer for
beginner to expert divers�
Please take the time to read this manual� Your safety
may depend on your ability to read and understand
your dive computer’s displays�
Diving involves risk and education is your best tool for
managing this risk�
Do not use this manual as a substitute for proper dive
training and never dive beyond your training� What you
don’t know can hurt you�

Page 5 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
1.2. Modes Covered by this Manual
This manual provides operating instructions for the
Petrel 3 in the following recreational operating modes:
• Air
• Nitrox
• 3 GasNx
• Gauge
The Shearwater Petrel 3 also has several modes
designed for open circuit technical and closed circuit
rebreather diving�
For detailed instructions on operation in technical
diving modes, please see the Petrel 3 Technical Mode
Manual.
Some features of the Petrel 3 only apply to certain
dive modes�
If not otherwise indicated, features described are
applicable in all dive modes�
Change the Dive Mode from the Mode Setup menu�
See details on page 53�
1.3. Models Covered by this Manual
This manual provides operating instructions for the
following Petrel 3 models in recreationl modes:
• Stand Alone Model SA
• Fischer Connector Model FC
• Analog Cable Gland Model ACG
Recreational mode features apply to all listed models�
1.1. Notes on this manual
This manual provides operating instructions for the
Petrel 3 dive computer in recreational operating
modes only�
This manual contains cross-references between
sections to make it easier to navigate�
Underlined text indicates the presence of a link to
another section�
Do not change any settings on your Petrel 3 without
understanding the consequence of the change. If
you are unsure, consult the appropriate section of the
manual for reference�
This manual is not a substitute for proper training�
Firmware Version: V91
This manual corresponds to firmware version V91�
Feature changes may have been made since this
release and might not be documented here�
Check the release notes on Shearwater.com for a
complete list of changes since the last release.

Page 6 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
2. Basic Operation
2.1. Turning On
To turn the Petrel 3 on, press both buttons together�
Auto-on Details
The Petrel 3 turns on automatically and enters dive
mode when the absolute pressure is greater than 1100
millibar (mbar)�
For reference, normal sea level pressure is 1013 mbar
and 1 mbar of pressure corresponds to approximately
1 cm (0�4”) of water� So, when at sea level, the Petrel 3
will automatically turn-on and enter dive mode when
about 0�9 m (3 ft) underwater�
If at higher altitude, then the Petrel 3 auto-on will
occur at a deeper depth� For example, when at 2000
m (6500 ft) altitude the atmospheric pressure is only
about 800 mbar� Therefore, at this altitude the Petrel
3 must be submerged underwater by 300 mbar to
reach an absolute pressure of 1100 mbar� This means
the auto-on occurs at about 3 m (10 ft) underwater
when at an altitude of 2000 m�
1.4. Customizable Splash Screen
After turning on, the Petrel 3 Splash Screen is
displayed for 2 seconds�
Customizable start up text can be added using the
Shearwater Cloud Desktop app�
The image itself can also be customized using the
Shearwater Cloud Desktop App�
Note that the computer will revert to the standard
splash screen on a firmware update� The custom
splash screen will then need to be reloaded�
See the section on Firmware Update and Log
Download on page 62 for details�
Auto-on
The Petrel 3 will automatically turn on when
submerged underwater� This is based on pressure
increase and not on the presence of water� When
auto-on is activated, the Petrel 3 will enter the last
configured dive mode�
Do Not Rely On The Auto-On Feature
This feature is supplied as a backup for
when you forget to turn on your Petrel 3�
Shearwater recommends turning your
computer on manually before each dive
to confirm proper operation and to
double check battery status and setup�

Page 7 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
2.2. Buttons
Two titanium piezo-electric buttons are used to
change settings and view menus�
All Petrel 3 operations are simple single button
presses�
MENU (left)
button
Button Hints
When in a menu, button hints indicate the function of
each button:
In the example above, the hints tell us:
• Use MENU to change the brightness value
• Use SELECT to save the current value
Don’t worry about remembering all the button rules
below� Button hints make using the Petrel 3 easy�
SELECT (right)
button
Brightness
Change Save
MedBrightness
MENU hint SELECT hint
MENU (Left) button
From main screen Brings up menu
In a menu Moves to the next menu item
Editing a setting Changes the setting’s value
SELECT (Left) button
From main screen Steps through info screens
In a menu Performs command or starts
editing
Editing a setting Saves the setting’s value
BOTH BUTTONS
When Petrel 3 is off pressing MENU and SELECT
at the same time will turn the Petrel 3 on� No other
operation requires pressing both buttons at the same
time�

Page 8 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
2.3. Changing between Modes
By default the Petrel 3 is set to 3 GasNx Mode�
This is the most complex
of the recreational
focused dive modes� All
recreational modes can
be distinguished by their
large-font layout�
This manual covers
operation in recreational
diving modes only�
Technical modes have a
dense layout compared
to recreational modes�
This provides space for
additional information
required for technical
diving at the expense of
font size�
For directions on how to
use the technical focused
modes on the Petrel 3,
see the Petrel 3 Technical
Modes Manual.
Shearwater recommends
using the simpler
recreational diving layout
for simple, single gas no-
decompression diving�
Switch between modes
in the mode setup menu�
See details on page 53�
300
Air 21
m
.o23°C
10:55am
MAX
.
7
:
:
Mode Air
Salinity EN13319
Next
Edit
Mode Setup
TIME
TTS
OC 21/00 12 3
O2/HE
NDL
PPO2
DEPTH
TIME
STOP
28.0
.80
4
3 GasNX Mode
Mode Setup Menu
OC Tec Mode
The different modes of this computer are
designed to fit the needs of different types of
divers� If you’re just starting out on your diving
adventure, we recommend keeping things
simple�
If you’re diving a single tank with air in it (21%
O2), we recommend you use the Air mode� If
diving a single tank of nitrox, we recommend
Nitrox mode�
The more advanced modes are more
complicated, with more rules that you need to
be aware of�
Mode Selection

Page 9 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
3. Dive Interface
3.1. Default Dive Setup
The Petrel 3 comes pre-configured for recreational
diving� The default dive mode is 3 Gas Nitrox mode (3
GasNx)�
As a quick reference, a diagram of the default diving
display is shown below�
The elements of the above default display are shared
by all of the dive modes covered in this manual�
For directions on how to use OC Tec, CC/BO, or other
technical dive modes, see the Petrel 3 Technical
Modes Manual.
The next section lists all the dive modes available
on the Petrel 3 stand alone model� Change the Dive
Mode from the Mode Setup menu� See details on page
53�
For infromation about other rebreather specific
modes used with external oxygen cells, see the Petrel
3 Technical Modes Manual.
Default Dive Display -
3 GasNx mode
3.2. Dive Mode Differentiation
Each dive mode is designed to best suit a particular
type of diving�
Air
Designed for use during recreational, air only,
no-decompression diving activities�
• Air (21% oxygen) only, not switchable underwater
Nitrox (Single Gas)
Designed for use during recreational, Nitrox,
no-decompression diving activities�
• Single Gas Nitrox up to 40% oxygen
• No gas switching underwater
3 GasNx (Three Gas Mode)
Designed for introductory technical diving activities
including diving involving planned decompression�
• Three programmable gases
• Support for gas switching
• Nitrox up to 100%
OC Tec
Designed for open circuit technical diving activities
including planned decompression�
• Full Trimix
• No Safety stops
CC/BO
Designed for use with a closed circuit rebreather�
• Fast switching from closed circuit to open circuit
(BO) operating modes�
Gauge
Gauge Mode turns the Petrel 3 into a simple depth
and time display with a dedicated layout (bottom
timer)� See details on page 36�
• No tissue tracking
• No decompression information
Ascent Rate
No-Deco
Limit
Dive Time
Active Gas
300
Air 21
m
.o23°C
10:55am
MAX
.
7
:
:
Depth
Safety Stop
Nitrogen
Loading
Temperature
Time

Page 10 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
Basic Dive Info
The Basic Dive area shows:
• The current depth (in feet or meters)
• The dive time in minutes and seconds
When on the surface, the dive time is replaced by
a surface interval timer� Also, a battery gauge will
appear in this area�
Decompression Info
The Decompression area shows:
• Safety stops (if enabled)
• Decompression stops
• No-Decompression Limit (NDL) in minutes
• Nitrogen loading bar graph
• Warnings for Maximum Operating Depth (MOD) and
Central Nervous System oxygen toxicity (CNS)
Configurable Info Row
The bottom-left position on the home screen always
shows the currently selected breathing gas�
The center and right positions can be configured
to display a variety of different information� By
default they show maximum depth, time of day and
temperature�
See “Configurable Info Row” on page 13 for
customization options�
Pressing the SELECT (right) button will cycle the Info
Row through additional data� Pressing the MENU (left)
button will return the info row to the home screen�
3.3. Main Screen
The Main Screen shows the most important
information for Air and Nitrox diving�
It is divided into three sections: Basic dive info,
decompression info, and the Info Row�
Basic Dive
Information
Depth, Time
& Ascent Rate
Decompression
Information
NDL, Safety Stops,
Deco Stops, Warnings
Info Row
Configurable
The Basic Dive Info section and the Decompression
Info section content are reserved for the most critical
information and are fixed� Pressing the right (SELECT)
button scrolls through additional data in the Info row�
300
Air 21
m
.o23°C
10:55am
MAX
.
7
:
:
Main Screen Sections

Page 11 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
3.4. Detailed Descriptions
Basic Dive Info Area
The Basic Dive Info Area shows depth, dive time,
ascent rate, and state of battery charge (when at the
12
20
6
GREEN when less than 9 mpm / 30 fpm
(1 to 3 arrows)
YELLOW when greater than 9 mpm /
30 fpm and less than 18 mpm / 60 fpm
(4 or 5 arrows)
FLASHING RED when greater than
18 mpm / 60 fpm (6 arrows)
BLUE when battery charge is OK
YELLOW when battery needs to
be charged�
RED when battery must be
charged immediately�
300
Air 21
m
.o23°C
10:55am
MAX
.7
:
:
surface)�
Depth
The depth is shown in the top
left� When in meters, one decimal
place is shown�
Note: If the depth shows a Flashing
Red zero or shows at depth at the
surface, then the depth sensor needs
service�
Dive Time
Dive time displays in minutes
and seconds� It begins and ends
counting automatically when you
dive�
Surface Interval
When on the surface, the dive
time is replaced by the surface
interval in hours and minutes�
Beyond 96 hours(4 days), it
displays in days�
Air 21
m
.o23°C
10:55am
MAX
:
ft
45
DECO STOP
6 2
m min
0
Ascent Rate Display
Shows how fast you are currently ascending graphically�
1 arrow per 3 meters per minute (mpm) or 10 feet per
minute (fpm) of ascent rate�
Depth in Meters
and Dive Time
Depth in Feet
and Dive Time
300
Air 21
m
.o23°C
10:55am
MAX
:
ft
0
SURFACE
22:15
h m
Surface interval
and battery
symbol
Note: Deco calculations assume 10mpm (33fpm)
ascent rate�
Battery Icon
The battery icon is shown on the surface but
disappears when diving� If low or critical then the
battery icon will appear while diving�
3:00
Air 21
m
.o23°C
10:55am
MAX
:
ft
0
SURFACE
22:15
h m
3:00
Air 21
m
.o23°C
10:55am
MAX
:
ft
0
SURFACE
22:15
h m
3:00
Air 21
m
.o23°C
10:55am
MAX
:
ft
0
SURFACE
22:15
h m
The surface interval resets
when decompression
tissues are cleared�
Due to variations in battery chemistry, battery
indicator (fuel gauge) accuracy differs between
different battery types� See Battery Type Selection on
page 65 for details�

Page 12 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
Nitrogen Loading bar Graph
The nitrogen bar graph is
scaled such that it is full once
decompression stops will be
needed�
On ascent, it gives a
much better indication of
decompression stress and
the risk of decompression
sickness than NDL does�
On the surface, the Nitrogen
Loading bar Graph shows the
residual nitrogen from the
previous dive�
Persistent Notifications
Persistent notifications are
displayed to the left of NDL�
If multiple warnings are
triggered, only the highest
priority will display�
See Notifications on page
21 for more information
on warnings�
Decompression Info Area
No Decompression Limit (NDL)
20
NDL
5
NDL
The time remaining, in minutes, at the
current depth until decompression stops
will be necessary�
Displays in Yellow when the NDL is less
than the low NDL limit (Default 5 minutes)�
Important!
All decompression information including
Deco Stops, NDL, and Time to surface are
predictions that assume:
• Ascent rate of 10mpm / 33fpm
• Decompression stops will be followed
• All programmed gases will be used as
appropriate
Read more about Decompression and
Gradient Factors on page 28�
300
Air 21
m
.o23°C
10:55am
MAX
.7
:
:
Air 21
m
.o23°C
10:55am
MAX
:
ft
45
DECO STOP
6 2
m min
0
NDL > 0 minutes
Safety Stop
suggested
NDL = 0 minutes
Decompression
Stops Required
Safety Stop
Appears when a safety stop is
recommended and counts down
automatically when in the safety
stop range�
Safety stops may be turned off,
set to fixed times of 3, 4, or 5
minutes, set to adapt based on
dive conditions, or be set to
count up from zero�
See Safety Stops on page 26
for details�
Deco Stop Depth and Time
Once NDL = 0 minutes,
mandatory decompression is
required� The safety stop counter
will be replaced by the shallowest
depth to which you can ascend
and how long to hold that stop�
See Decompression Stops on
page 27 for details�
500
Air 21
m
.o23°C
10:55am
MAX
.7
:
:
3

Page 13 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
Active Gas
The active gas position is not configurable� It always
shows the currently selected breathing gas�
Configurable Info Row
The Home Screen is the default display for the info
row� Information in the center and right positions can
be customized�
Configurable Center & Right Positions
Many possible configurations can be set for the center
and right positions of the bottom row�
Default Info row
500
Air 21
m
.o23°C
10:55am
MAX
.7
:
:
3
500
Air 21
m
.o23°C
10:55am
MAX
.7
:
:
3
5:00
Nx32 21
m
.o23°C
10:55am
MAX
.7
:
:
3
5:00
m
.o23°C
10:55am
MAX
.7
:
:
3
Nx32 21
Lorem ipsum
21% O2
32% O2
Better Gas
available
When air (21% O2) is used, the value “Air’
is displayed�
For all other gases, it displays “Nx”
(Nitrox) followed by the O2%�
The gas will display in yellow if a better
gas is available� (3 GasNx mode only)
The gas will display in flashing red if the
MOD of the gas has been exceeded�
5:00
m
.o23°C
10:55am
MAX
.7
:
:
3
Nx32 21
5:00
m
.o23°C
10:55am
MAX
.7
:
:
3
Nx32 21
Gas displayed in flashing red
when MOD has been exceeded
300
Air
.
7
:
:
15 62
SurGF
GF99
% %
Bottom Row
Center GF99
SurGF
GF99
SurGF
15 62 % %
Change Save
All recreational dive modes share the same home
screen customization options� If you customize
your home screen in Air mode, that same custom
configuration will be present when you put your
computer in Nitrox mode�
See details for how to change the configuration of the
Bottom Row on page 57�
All bottom row options are listed on the next page�
Descriptions of each function can be found in the next
section (INFO Screens)

Page 14 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
Home Screen Configuration Options
Option Info Display
PPO2
CNS %
MOD
Gas Density
GF99
Surface GF
Ceiling
@+5
Δ+5
Time To
Surface
Dil� PPO2
FiO2
Mini Display
Option Info Display
CLOCK
Timer
Dive End
Time
RATE
Temperature
Compass
Max Depth
Avg� Depth
Tank
Pressure
Surface Air
Consumption
Gas Time
Remaining
Redundant
Time
Remaining
Mini Displays for the left
and right custom slots can
each hold 3 data displays�
Mini Displays
TIME
TTS
OC 50/00 0 27
O2/HE
NDL
11
CEIL
13.2 36 12 2
DEPTH
TIME
STOP
GF9937
%
Δ+5 -4
MOD 22m
PO21.09
CNS 21%
SfGF
180
STOP
TTS
OC 15/40
O2/HE
NDL
DEPTH
TIME
Δ
Δ +5
PPO2
61.0
1.15
0
+8
TIME
56
22 39 1
SurGF
%
83
STOP
TTS
OC 15/40
O2/HE
NDL
DEPTH
TIME
@+5
PPO2
61.0
1.15
0
20
TIME
56
22 39 1
SurGF
%
83
STOP
TTS
OC 15/40
O2/HE
NDL
DEPTH
TIME
CEIL
PPO2
61.0
1.15
0
17
TIME
56
22 39 1
SurGF
%
83
TIME
TTS
OC 21/00 0 3
O2/HE
NDL
24.0 22
DEPTH
TIME
STOP
SurGF
44
DENSITY
13
g
L
PPO2
71
%
TIME
TTS
OC 21/00 0 3
O2/HE
NDL
24.0 22
DEPTH
TIME
STOP
GF99
15
DENSITY
13
g
L
PPO2
71
%
TIME
TTS
OC 21/00 0 3
O2/HE
NDL
24.0 22
DEPTH
TIME
STOP
SurGF
44
DENSITY
13
g
L
PPO2
71
%
STOP
TTS
OC 15/40
O2/HE
NDL
DEPTH
TIME
MOD
m
PPO2
61.0
1.15
0
57
TIME
56
22 39 1
.3
SurGF
%
83
STOP
TTS
OC 15/40
O2/HE
NDL
DEPTH
TIME
CNS
PPO2
61.0
1.15
0
11
TIME
56
22 39 1
SurGF
%
83
STOP
TTS
OC 15/40
O2/HE
NDL
DEPTH
TIME
MAX
m
PPO2
61.0
1.15
0
70
TIME
56
22 39 1
.7
SurGF
%
83
STOP
TTS
OC 15/40
O2/HE
NDL
DEPTH
TIME
Δ
TTS
PPO2
61.0
1.15
0
15
TIME
56
22 39 1
SurGF
%
83
STOP
TTS
OC 15/40
O2/HE
NDL
DEPTH
TIME
Δ
DilPO2
PPO2
61.0
1.15
0
.99
TIME
56
22 39 1
SurGF
%
83
STOP
TTS
OC 15/40
O2/HE
NDL
DEPTH
TIME
Δ
FiO2
PPO2
61.0
1.15
0
.32
TIME
56
22 39 1
SurGF
%
83
TIME
TTS
OC 50/00 0 27
O2/HE
NDL
11
CEIL
13.2 36 12 2
DEPTH
TIME
STOP
GF99
37%
Δ+5 -4
MOD 22m
PO21.09
CNS 21%
SfGF
180
TIME
24.0 14
DEPTH
TIME
STOP
R
T1
175
B
A
37
GTR T1 SAC T1
1.5
Bar
min
3:00
57 21 3.13
m
.3
AVG
.7
:
:
MAX
m
AvgATM
.o
3:00
57 21 3.13
m
.3
AVG
.7
:
:
MAX
m
AvgATM
.o
3:00
319

.7
:
:
DATE
18C
TEMP
43
RATE
ft
min
STOP
TTS
OC 15/40
O2/HE
NDL
DEPTH
TIME
Δ
DET
PPO2
61.0
1.15
0
TIME
56
22 39 1
SurGF
%
831:31
STOP
TTS
OC 15/40
O2/HE
NDL
DEPTH
TIME
Δ
TIMER
PPO2
61.0
1.15
0
0:58
TIME
56
22 39 1
SurGF
%
83
STOP
TTS
OC 15/40
O2/HE
NDL
DEPTH
TIME
Δ
CLOCK
PPO2
61.0
1.15
0
12:58
TIME
56
22 39 1
SurGF
%
83
TIME
24.0 14
DEPTH
TIME
STOP
R
T1
175
B
A
37
GTR T1 SAC T1
1.5
Bar
min
TIME
24.0 14
DEPTH
TIME
STOP
R
T1
175
B
A
37
GTR T1 SAC T1
1.5
Bar
min
TIME
24.0 14
DEPTH
TIME
STOP
R
T1
175
B
A
16
RTR T1 SAC T1
1.5
Bar
min
3.5. Mini Displays
Mini displays provide more options for data
customization at the expense of font size�
There 2 separately configurable mini displays that
are shared by all recreational modes� By default mini
display 1 is in the right slot of the bottom row and
contains temperature and time�
Details about how to customize the mini displays can
be found on page 57
Up to 6 customizable fields can be displayed
simultaneously with fully populated Mini Displays,
Managed improperly, this can be an overwhelming
amount of information�
Care should be taken not to distract from important
information such as NDL and gas pressure remaining�
300
Air
23°C
10:55am
.
7
:
:
MAX 26m
PO2 .54
MOD 56m
Mini 2 Mini 1
Top
Center
None
TEMP
Change Save
Mini 1 Setup
Bottom CLOCK
77F
10:51pm

Page 15 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
3.6. Info Screens
Info screens provide more information than is
available on the main screen�
From the main screen, the SELECT (right) button
steps through info screens�
When all info screens have been viewed, pressing
SELECT again will return to the main screen�
Info screens also automatically time-out after 10
seconds, returning to the home screen� This prevents
active gas information from being hidden for an
extended period�
Note that the Compass, Tissues and AI Info screens do
not automatically time out when active�
Pressing the MENU (left) button will return to the
home screen at any time�
Although these screens are generally representative
of the Petrel 3 display, info screen content varies for
each mode� For example, decompression related info
screens are not available in gauge mode�
The next section gives detailed descriptions of the
data elements shown on the info screens�
3:00
12 52 -20/ 2
Δ+5
.7
:
:
DET @+5/TTS
:
Press the left (FUNC)
button, to step through
Info Screens
Return to Main Screen by:
•Pressing the right (MENU) button
•Stepping past last screen
•Waiting 10 Seconds (most screens)
300
Air 21
m
.o23°C
10:55am
MAX
.7
:
:
3:00
57 21 .54
m
.o
MAX
.7
:
:
MOD
m
PPO2
3:00
20 0
CONSERV
.7
:
:
TEMP
°C
CNS
Med
40/85
3:00
15 62 0
SurGF
.7
:
:
GF99
%
CEIL
%
3:00
.7
:
:
TISSUES
3:00
4 . 12V
1.5V
.7
:
:
Alka
BATTERY
3:00
1020 1021
.7
:
:
PRESSURE mBar
SURF NOW
3:00
03-Mar-20 6 42
.7
:
:
DATE CLOCK
:
3:00
9F1F0432 20080BC
.7
:
:
SERIAL NO VERSION
SAFETY STOP
SURFACE
h
NDL
00
LAST DIVE
0
ft
N2
m
01
37
#1234
MAX m 0 h 52 m 38 s
.6
TIME
NE
N
24
1.30
22.1 3
DEPTH
TIME
STOP
TIME
24.0 14
DEPTH
TIME
STOP
R
T2
163
B
A
R
T1
175
B
A
GTR 45
SM
SAC 1.5

Page 16 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
Compass
Marked headings appear in green while reciprocal
headings are shown in red� Green arrows point in the
direction of your mark when off course by 5˚ or more�
Compass info row will not time out and is only
available when compass feature is turned on�
See the Compass section on page 34 for more
information�
Maximum Operating Depth
MOD is the maximum allowable
depth of the current breathing gas
as determined by PPO2 limits�
Displays in Flashing Red when
exceeded�
Maximum Depth
The maximum depth of the current
dive� When not diving, displays the
maximum depth of the last dive
Partial Pressure of Oxygen (PPO2)
PPO2 of the current breathing gas�
Displays in Flashing Red when
outside PPO2 limits�
Temperature
The current temperature in degrees
Celsius or degrees Fahrenheit�
Temperature units can be set in the
Display settings menu�
3.7. Info Screen Descriptions
Last Dive Info Screen
Maximum depth and dive time from the last dive� Only
available at the surface�
Air Integration
Only available if AI feature is turned on� The contents
of the AI info line will automatically adapt to the
current setup� Some examples include:
More information on AI features, limitations, and
displays can be found in the Air Integration (AI)
section on page 35�
3:00
57 21 .54
m
.o
MAX
.7
:
:
MOD
m
PPO2
3:00
20 0
CONSERV
.7
:
:
TEMP
°C
CNS
Med
40/85
SAFETY STOP
SURFACE
h
NDL
00
LAST DIVE
0
ft
N
2
m
01
105
#1234
MAX ft 0 h 52 m 38 s
T1 Only
T1 & GTR/SAC
T1 & T2
T1, T2 &
GTR/SAC
T1, T2, T3,
& T4
TIME
24.0 14
DEPTH
TIME
STOP
R
T1
175
B
A
TIME
24.0 14
DEPTH
TIME
STOP
R
T1
175
B
A
37
GTR T1 SAC T1
1.5
Bar
min
TIME
24.0 14
DEPTH
TIME
STOP
R
T2
163
B
A
R
T1
175
B
A
TIME
24.0 14
DEPTH
TIME
STOP
R
T2
163
B
A
R
T1
175
B
A
GTR 45
SM
SAC 1.5
TIME
24.0 14
DEPTH
TIME
STOP
R
T2
163
B
A
R
T1
175
B
A
T3 197
T4 203
54.0 22
DEPTH
TIME
30
R
T1
107
B
AR
129
B
A
124
%
SurGF
STOP
TIME
1
T2
STOP
TTS
OC 15/40
O2/HE
NDL
DEPTH
TIME
MOD
m
PPO2
61.0
1.15
0
57
TIME
56
22 39 1
.3
SurGF
%
83
3:00
57 21 3.13
m
.3
AVG
.7
:
:
MAX
m
AvgATM
.o

Page 17 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
Conservatism
The conservatism level and
values for the Bühlmann GF
decompression algorithm�
Read more about Decompression and Gradient
Factors on page 28�
CNS Toxicity Percentage
Central Nervous System oxygen
toxicity loading percentage (CNS)�
Turns Yellow when greater than
90%� Turns Red when greater than
150%�
The CNS percentage is calculated
continuously, even when the dive
computer is on the surface and
turned off� When deco tissues are
reset, the CNS will also be reset�
The CNS value (short for Central Nervous System
Oxygen Toxicity) is a measure of how long you have
been exposed to elevated partial pressures of oxygen
(PPO2) as a percentage of a maximum allowable
exposure� As PPO2 goes up, the maximum allowable
exposure time goes down� The table we use is from
the NOAA Diving Manual (Fourth Edition)� The
computer linearly interpolates between these points
and extrapolates beyond them when necessary�
Above a PPO2 of 1�65 ATA, the CNS rate increases at a
fixed rate of 1% every 4 seconds�
During a dive the CNS never decreases� When back at
the surface, a half-life of elimination of 90 minutes is
used�
For example, if at the end of the dive the CNS was
80%, then 90 minutes later it will be 40%� In 90 more
minutes it will be 20%, etc� Typically, after about 6
half-life times (9 hours), everything has returned close
to equilibrium (0%)�
3:00
20 0
CONSERV
.7
:
:
TEMP
°C
CNS
Med
40/85
MODCNS
%
11
mmin
PPO2
.21271
SURFACE
MODCNS
%
101
mmin
PPO2
.21271
SURFACE
GF99
The current gradient factor as
a percentage of the controlling
compartment m-value (i�e� super-
saturation percent gradient)
0% means the leading tissue super-saturation is equal
to ambient pressure� Displays “On Gas” when tissue
tension is less than the inspired inert gas pressure�
100% means the leading tissue super-saturation is
equal to the original M-Value limit in the Bühlmann
ZHL-16C model� This should never reach 100%�
GF99 is displayed in Yellow when the current gradient
factor modified M-Value (GF High) is exceeded�
GF99 is displayed in Red when 100% (un-modified
M-Value) is exceeded�
GF99 is most interesting to look at during ascent� It
can be thought of as a simplified indicator of current
decompression stress� GF99 reaches a maximum right
when you surface� Surfacing with a lower GF99 is
generally thought to be more conservative�
Surface GF
The surfacing gradient
factor expected if the diver
instantaneously surfaced�
SurGF colour is based on the current GF (GF99)� If
the current GF is greater than GF High, SurGF will be
displayed in Yellow� If the current gradient factor is
greater than 100%, SurGF will be displayed in Red.
If GF99 is an indicator of current decompression
stress, SurGF is a predictor of future decompression
stress if you were to suddenly surface� SurGF is always
interesting to look at, but watching it fall while on
your safety stop gives you a sense of the safety stop’s
effectiveness at reducing risk�
3:00
15 62 0
SurGF
.7
:
:
GF99
%
CEIL
%
3:00
15 62 0
SurGF
.7
:
:
GF99
%
CEIL
%

Page 18 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
Rate
Numerically displays the rate of
ascent or decent in feet or meters
per minute� Only available in a
configurable data location�
Gas Density Display
The Gas Density display is only
available as a customizable display
and is not available in the info row�
For open circuit diving, the gas
density display turns yellow at 6�3
grams per liter� No other warnings
are generated�
You may be surprised at how shallow the gas density
warning color appears�
Read more about why we chose these levels starting
on page 66 here (recommendations on page 73):
Anthony, T.G and Mitchell, S.J. Respiratory physiology
of rebreatherdiving. In: Pollock NW, Sellers SH,
Godfrey JM, eds. Rebreathers and Scientific Diving.
Proceedings of NPS/NOAA/DAN/AAUS June 16-19,
2015 Workshop. Durham, NC; 2016.
Timer
A simple stopwatch� The timer is
only available as a customizable
display� It is not available in the info
row�
Mini Compass
A small compass that can be
displayed at all times� The red arrow
always points toward north�
Only available as a custom display
Ceiling
The current decompression ceiling
not rounded to the next deeper
stop increment� (i�e� not a multiple
of 10ft or 3m)� Only useful in
decompression diving�
Time To Surface
The Time-To-Surface (TTS) in
minutes� This is the current time to
ascend to the surface including the
ascent plus all required deco stops
and safety stops�
@+5
“At plus 5” is the TTS if remaining
at the current depth for 5 more
minutes� This can be used as a
measure of how fast you are on-
gassing or off-gassing while in
decompression�
Δ+5
“Delta plus 5” is the predicted
change in TTS if you were to
stay at the current depth for 5
more minutes� Most useful in
decompression�
(Δ+5) = (@+5)-(TTS)
Dive End Time (DET)
The time of day at which you
can expect to surface if you
depart immediately, ascend at
10mpm or 33fpm, change gases
when prompted, and perform all
decompression stops as directed�
Most useful in decompression
diving where TTS could be high�
3:00
12 52 00/ 0
Δ+5
.7
:
:
DET @+5/TTS
:
3:00
12 52 00/ 0
Δ+5
.7
:
:
DET @+5/TTS
:
3:00
12 52 00/ 0
Δ+5
.7
:
:
DET @+5/TTS
:
125
14
T1
min
TTS
23
43
RATE
ft
min
TIME
TTS
OC 21/00 0 3
O2/HE
NDL
24.0 22
DEPTH
TIME
STOP
SurGF
44
DENSITY
13
g
L
PPO2
71
%
TIME
TTS
OC 21/00 0 3
O2/HE
NDL
24.0 22
DEPTH
TIME
STOP
SurGF
44
DENSITY
63
g
L
PPO2
71
%
3:00
03-Mar-20 5 42
.7
:
:
DATE TIMER
:
3:00
319

.7
:
:
DATE
3:00
15 62 0
SurGF
.7
:
:
GF99
%
CEIL
%

Page 19 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
Sample Tissue bar GraphsTissues bar Graph
The tissues bar graph shows the tissue compartment
inert gas tissue tensions based on the Bühlmann ZHL-
16C model�
Each bar represents the nitrogen inert gas tension for
one compartment� The fastest tissue compartment
is shown on the top, and the slowest on the bottom�
Pressure increases to the right�
The vertical black line shows the inspired partial
pressure of nitrogen� The green-yellow interface line is
the ambient pressure� The yellow-red interface line is
the ZHL-16C M-Value pressure�
Tissues that are supersaturated above ambient
pressure extend into the yellow, and tissues that are
supersaturated above the M-Value extend into the red�
Note that the scale for each tissue compartment is
different� The reason the bars are scaled in this way is
so that the tissues tensions can be visualized in terms
of risk (i�e� how close they are as a percentage to
Bühlmann’s original super-saturation limits)� Also, this
scale changes with depth, since the M-Value line also
changes with depth�
Inspired inert
gas pressure
Ambient
Pressure
Increasing
Pressure
M-Value
Pressure
16 tissue
compartments
{
On surface (sat� with air)
Note: Gas is 79% N2 (21% O2, or Air)
Immediately after descent
Deepest Stop
On Gassing
Last deco Stop
Note: Gas is now 50% O2and 50% N2
mmin
SURFACE
TISSUES
3:00
.7
:
:
TISSUES
3:00
.7
:
:
TISSUES
3:00
.7
:
:
TISSUES
3:00
.7
:
:
TISSUES
3:00
.7
:
:
TISSUES
3:00
.7
:
:
TISSUES
3:00
.7
:
:
TISSUES

Page 20 Doc. 13300-REC-RevB (2022-05-02)
Recreational Modes
Operating Instructions
Pressure
The pressure in millibar� Two values are shown,
the surface (surf) pressure and the current (now)
pressure�
Note that typical pressure at sea level is 1013 millibar,
although it may vary with the weather (barometric
pressure)� For example, in a low pressure system
surface pressure may be as low as 980 millibar, or as
high as 1040 millibar in a high pressure system�
For this reason, the PPO2 displayed on the surface
may not exactly match the FO2 (fraction of O2),
although the displayed PPO2 is still correct�
The surface pressure is set based on the lowest
pressure the Petrel 3 sees in the 10 minutes prior to
computer turn on� Therefore, altitude is automatically
accounted for and no special altitude setting is
required�
Battery
Current voltage of the internal
battery� Displays in yellow when
battery is low and needs to be
replaced� Displays in red when
battery is critically low and must be
replaced immediately�
Clock
In a 12 or 24 hour format� Time
format can be changed in the watch
settings menu�
Date
In the format Day-Month Year�
3:00
1020 1021
.7
:
:
PRESSURE mBar
SURF NOW
3:00
03-Mar-20 6 42
.7
:
:
DATE CLOCK
:
3:00
03-Mar-20 6 42
.7
:
:
DATE CLOCK
:
3:00
4 . 12V
1.5V
.7
:
:
Alka
BATTERY