Suunto Gekko User manual

www.suunto.com
INSTRUCTION MANUAL
Gekko
GEKKO
Valimotie 7
FIN-01510 Vantaa, Finland
Tel. [phone]
Fax [phone]
www.suunto.com
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1
WARNING is used in connection with a procedure or situation
that may result in serious injury or death.
CAUTION is used in connection with a procedure or situation
that will result in damage to the product.
NOTE is used to emphasize important information.
DEFINITION OF WARNINGS, CAUTIONS AND NOTES
Throughout this manual, special references are made when deemed im-
portant. Three classifications are used to separate these references by their
order of importance.
COPYRIGHT, TRADEMARK AND PATENT NOTICE
This instruction manual is copyrighted and all rights are reserved. It may
not, in whole or in part, be copied, photocopied, reproduced, translated, or
reduced to any media without prior written consent from SUUNTO.
SUUNTO, GEKKO, Consumed Bottom Time (CBT), Oxygen Limit Frac-
tion (OLF), SUUNTO Reduced Gradient Bubble Model (RGBM), Con-
tinuous Decompression and their logos are all registered or unregistered
trademarks of SUUNTO. All rights are reserved.
CE
The CE mark is used to mark conformity with the European Union EMC
directive 89/336/EEC.
The instruments must be serviced by an authorized dealer every second
year or after 200 dives (whichever comes first).
EN 13319
EN 13319 “Diving accessories - Depth gauges and combined depth and
time measuring devices - Functional and safety requirements, test meth-
ods” is a European diving depth gauge standard. The GEKKO is designed
to comply with this standard.

2
ISO 9001
SUUNTO Oy’s Quality Assurance System is certified by Det Norske Veritas to
be according to the ISO 9001 in all SUUNTO Oy’s operations (Quality Certifi-
cate No. 96-HEL-AQ-220).
SUUNTO Oy does not assume any responsibility for losses or claims by third
parties, which may arise through the use of this device.
Due to continuous product development, the GEKKO is subject to change with-
out notice.

3
WARNING!
READ THIS MANUAL! Carefully read this instruction manual in its en-
tirety paying close attention to all warnings listed below, including section
1.1. “Safety Precautions”. Make sure that you fully understand the use, dis-
plays and limitations of the dive computer because any confusion resulting
from neglecting to follow this instruction manual or from improper use of
this device may cause a diver to commit errors that may lead to serious injury
or death.
WARNING!
NOT FOR PROFESSIONAL USE! Suunto dive computers are intended for
recreational use only. The demands of commercial or professional diving may
expose the diver to depths and exposures that tend to increase the risk of
decompression illness (DCI). Therefore, Suunto strongly recommends that
the device be not used for commercial or professional diving activity.
WARNING!
ONLY DIVERS TRAINED IN THE PROPER USE OF SCUBA DIVING
EQUIPMENT SHOULD USE A DIVE COMPUTER! No dive computer can
replace the need for proper dive training. Insufficient or improper training
may cause diver to commit errors that may lead to serious injury or death.
WARNING!
THERE IS ALWAYS A RISK OF DECOMPRESSION ILLNESS (DCI) FOR
ANY DIVE PROFILE EVEN IF YOU FOLLOW THE DIVE PLAN PRE-
SCRIBED BY DIVE TABLES OR A DIVE COMPUTER. NO PROCE-
DURE, DIVE COMPUTER OR DIVE TABLE WILL PREVENT THE POS-
SIBILITY OF DCI OR OXYGEN TOXICITY! An individual’s physiologi-
cal make up can vary from day to day. The dive computer cannot account for
these variations. You are strongly advised to remain well within the exposure
limits provided by the instrument to minimize the risk of DCI. As an added
measure of safety, you should consult a physician regarding your fitness be-
fore diving.

4
WARNING!
SUUNTO STRONGLY RECOMMENDS THAT SPORT DIVERS LIMIT
THEIR MAXIMUM DEPTH TO 40 M [130 FT] OR TO THE DEPTH CAL-
CULATED BY THE COMPUTER BASED ON THE SELECTED O2% AND
A MAXIMUM PO2OF 1.4 BAR!
WARNING!
DIVES WITH REQUIRED DECOMPRESSION STOPS ARE NOT REC-
OMMENDED. YOU SHOULD ASCEND AND BEGIN DECOMPRESSION
IMMEDIATELY WHEN THE DIVE COMPUTER SHOWS YOU THAT A
DECOMPRESSION STOP IS REQUIRED! Note the blinking ASC TIME
symbol and the upward pointing arrow.
WARNING!
USE BACK-UP INSTRUMENTS! Make sure that you use back-up instru-
mentation including a depth gauge, submersible pressure gauge, timer or
watch, and have access to decompression tables whenever diving with the
dive computer.
WARNING!
PERFORM PRECHECKS! Always activate and check the device before div-
ing in order to ensure that all Liquid Crystal Display (LCD) segments are
completely displayed, that the device has not run out of battery power, and
that the oxygen, altitude and personal adjustments are correct. Also, exit the
PC Settings (PC SET) sub-mode before diving, as the computer does not
automatically revert to Dive mode from the PC Settings mode.
WARNING!
YOU ARE ADVISED TO AVOID FLYING ANY TIME THE COMPUTER
COUNTS DOWN THE NO-FLYING TIME. ALWAYS ACTIVATE THE
COMPUTER TO CHECK THE REMAINING NO-FLY TIME PRIOR TO
FLYING! The computer goes into the stand-by display automatically 5 min-
utes after the dive has ended. The stand-by display shuts off after two hours.
Flying or traveling to a higher altitude within no-fly time can greatly increase
the risk of DCI. Review the recommendations given by Diver’s Alert Net-

5
work (DAN) in chapter 3.5.3. “Flying After Diving”. There can never be a
flying after diving rule that is guaranteed to completely prevent decompres-
sion illness!
WARNING!
THE DIVE COMPUTER SHOULD NEVER BE TRADED OR SHARED
BETWEEN USERS WHILE IT IS IN OPERATION! Its information will not
apply to someone who has not been wearing it throughout a dive or sequence
of repetitive dives. Its dive profiles must match that of the user. If it is left on
the surface during any dive, it will give inaccurate information for subse-
quent dives. No dive computer can take into account dives made without the
computer. Thus any diving activity up to four days prior to initial use of the
computer may cause misleading information and must be avoided.
WARNING!
THE DIVE COMPUTER WILL NOT ACCEPT FRACTIONAL PERCENT-
AGE VALUES OF OXYGEN CONCENTRATION. DO NOT ROUND UP
FRACTIONAL PERCENTAGES! For example, 31.8% oxygen should be
entered as 31%. Rounding up will cause nitrogen percentages to be under-
stated and will affect decompression calculations. If there is a desire to adjust
the computer to provide more conservative calculations, use the personal ad-
justment feature to affect decompression calculations or reduce the PO2set-
ting to affect oxygen exposure.
WARNING!
SET THE CORRECT ALTITUDE ADJUSTMENT MODE! When diving at
altitudes greater than 300 m [1000 ft] the Altitude Adjustment feature must
be correctly selected in order for the computer to calculate the decompres-
sion status. The dive computer is not intended for use at altitudes greater than
3000 m [10000 ft]. Failure to select the correct Altitude Adjustment setting
or diving above the maximum altitude limit will result in erroneous dive and
planning data.

6
WARNING!
SET THE CORRECT PERSONAL ADJUSTMENT MODE! Whenever it is
believed that factors that tend to increase the possibility of DCI exist, it is
recommended that you use this option to make the calculations more conser-
vative. Failure to select the correct Personal Adjustment setting will result in
erroneous dive and planning data.
NOTE!
You can change from Air mode to Nitrox mode at any time. It is however not
possible to revert back to Air mode from Nitrox mode before the instrument has
counted down the no-flying time.
When planning both air and nitrox dives during the same dive series, you should
set the instrument in Nitrox mode and modify the gas mix accordingly.

7
TABLE OF CONTENTS
WARNINGS .................................................................................. 3
1. INTRODUCTION ..................................................................... 9
1.1. SAFETY PRECAUTIONS .......................................................... 9
1.1.1. Emergency Ascents .............................................................. 10
1.1.2. Dive Computer Limitations ................................................... 10
1.1.3. Nitrox ..................................................................................... 10
2. GETTING ACQUAINTED ..................................................... 12
2.1. FUNCTIONS .............................................................................. 12
2.2. PUSH BUTTONS ....................................................................... 12
2.3. WATER CONTACTS .................................................................. 14
3. DIVING WITH THE GEKKO ................................................ 15
3.1 BEFORE DIVING ....................................................................... 15
3.1.1. Activation and Prechecks ....................................................... 15
3.1.2. Battery Indication .................................................................. 17
3.1.2.1. Battery Power Indicator ........................................... 17
3.1.3. Dive Planning [PLAN] .......................................................... 18
3.1.4. User Definable Functions and Alarms ................................... 19
3.2. SAFETY STOPS ........................................................................ 19
3.2.1. Recommended Safety Stop .................................................... 19
3.2.2. Mandatory Safety Stop .......................................................... 19
3.3. DIVING WITH THE GEKKO ................................................... 20
3.3.1. Basic Dive Data ..................................................................... 20
3.3.2. Bookmark .............................................................................. 21
3.3.3. Consumed Bottom Time (CBT) ............................................ 22
3.3.4. Ascent Rate Indicator ............................................................ 22
3.3.5. Decompression dives ............................................................. 23
3.4. DIVING IN NITROX MODE .................................................... 27
3.4.1. Before Diving ........................................................................ 27
3.4.2. Oxygen Displays.................................................................... 28
3.4.3. Oxygen Limit Fraction (OLF) ............................................... 29
3.5. AT THE SURFACE .................................................................... 30
3.5.1. Surface Interval ...................................................................... 30
3.5.2. Dive Numbering .................................................................... 31
3.5.3. Flying After Diving ............................................................... 31
3.6. AUDIBLE AND VISUAL ALARMS ........................................ 33

8
3.7. HIGH ALTITUDE DIVES AND
PERSONAL ADJUSTMENT ...................................................... 34
3.7.1. Altitude Adjustment .............................................................. 34
3.7.2. Personal Adjustment .............................................................. 35
3.8. ERROR CONDITIONS .............................................................. 36
4. MENU BASED MODES ........................................................ 37
4.1. MEMORY FUNCTIONS [1 MEMORY] ................................... 38
4.1.1. Logbook and Dive Profile Memory [1 LOGBOOK] ............. 39
4.1.2. Dive History Memory [2 HISTORY] .................................... 42
4.1.3. PC Settings Mode [3 PC SET] .............................................. 42
4.2. SET MODES [4 SET] ................................................................. 43
4.2.1. Dive Computer Model Settings[1 SET MODEL ] ................ 43
4.2.1.1. Nitrox Oxygen Settings ........................................... 43
4.2.2. Alarm settings [2 SET ALMS] .............................................. 43
4.2.2.1. Dive Time Alarm Setting ......................................... 44
4.2.2.2. Maximum Depth Alarm Setting .............................. 44
4.2.3. Setting Time and date [3 SET TIME] .................................... 44
4.2.4. Personal adjustments [4 SET ADJ] ....................................... 44
5. CARE AND MAINTENANCE .............................................. 46
5.1. IMPORTANT INFORMATION ................................................. 46
5.2. CARE OF YOUR DIVE COMPUTER ...................................... 46
5.3. MAINTENANCE ....................................................................... 47
5.4. WATER RESISTANCE INSPECTION ...................................... 47
5.5. BATTERY REPLACEMENT ..................................................... 48
6. TECHNICAL DESCRIPTION ............................................... 52
6.1. OPERATING PRINCIPLES ....................................................... 52
6.2. SUUNTO REDUCED GRADIENT BUBBLE
MODEL (RGBM) ....................................................................... 54
6.3. OXYGEN EXPOSURE .............................................................. 55
6.4. TECHNICAL SPECIFICATION ................................................ 55
7. WARRANTY .......................................................................... 59
8. SUUNTOSPORTS.COM ........................................................ 60
8.1. SYSTEM REQUIREMENTS ..................................................... 60
8.2. SUUNTOSPORTS.COM SECTIONS ........................................ 60
8.3. GETTING STARTED ................................................................. 61
9. GLOSSARY ............................................................................ 62

9
1. INTRODUCTION
Congratulations on your purchase of the SUUNTO GEKKO dive computer. The
GEKKO builds on the Suunto tradition of delivering feature-rich easy-use dive
computers. Push button controls access a wide selection of choices and the dis-
play is optimized for the dive mode chosen. This dive computer is a compact
and sophisticated multipurpose dive instrument, designed to give you years of
trouble-free service.
Choice of Operating Modes and Set-up Options
User options for the GEKKO are selected using the push buttons.
Pre Dive configuration and setup options include:
•Choice of operating mode - Air / Nitrox
•Choice of unit - Metric / Imperial
•Maximum depth alarm
•Dive time alarm
•Clock, calendar
•Mix Oxygen fraction % (Nitrox mode only)
•Maximum PO2(Nitrox mode only)
•Altitude adjustment
•Personal adjustment
Continuous Decompression with Suunto RGBM
The Suunto Reduced Gradient Bubble Model (RGBM) utilized in the GEKKO
predicts both dissolved and free gas in blood and tissues of divers. It is a signif-
icant advance on the classic Haldane models, which do not predict free gas. The
advantage of Suunto RGBM is additional safety through its ability to adapt to a
variety of situations and dive profiles.
In order to optimize how to respond to different added risk situations an addi-
tional category of stop, referred to as a Mandatory Safety Stop, has been intro-
duced. Also a countdown for the Recommended Safety Stop is included. The
combination of stop types will depend on the specific dive situation.
To get the most from the safety benefits be sure to read the summary of the
Reduced Gradient Bubble Model in chapter 6.2.
1.1. SAFETY PRECAUTIONS
Do not attempt to use the dive computer without reading this instruction manual
in its entirety, including all the warnings. Make sure that you fully understand

10
the use, displays and limitations of the instrument. If you have any questions
about the manual or the dive computer, contact your SUUNTO dealer before
diving with the dive computer.
Always remember that YOU ARE RESPONSIBLE FOR YOUR OWN SAFE-
TY!
When used properly, the dive computer is an outstanding tool for assisting prop-
erly trained, certified divers in planning and executing sport dives. It is NOT A
SUBSTITUTE FOR CERTIFIED SCUBA INSTRUCTION, including training
in the principles of decompression.
Diving with enriched air mixtures (nitrox) exposes the user to risks different
from those associated with diving with standard air. These risks are not obvious
and require training to understand and avoid. Risks include possible serious in-
jury or death.
Do not attempt to dive with any gas mix other than standard air without first
receiving certified training in this specialty.
1.1.1. Emergency Ascents
In the unlikely event that the dive computer malfunctions during a dive, follow
the emergency procedures provided by your certified dive training agency or,
alternatively,
STEP 1: Assess the situation calmly and then move promptly to less than 18
m [60 ft].
STEP 2: At 18 m [60 ft], slow down your ascent rate to 10 m/min [33 ft/min]
and move to a depth between 3 and 6 meters [10 to 20 ft].
STEP 3: Stay there as long as you assess your air supply will safely allow.
After reaching the surface stay out of the water for at least 24 hours.
1.1.2. Dive Computer Limitations
While the dive computer is based on current decompression research and tech-
nology, you must realize that the computer cannot monitor the actual physiolog-
ical functions of an individual diver. All decompression schedules currently
known to the authors, including the U.S. Navy Tables, are based on theoretical
mathematical models, which are intended to serve as a guide to reduce the prob-
ability of decompression illness.
1.1.3. Nitrox
Diving with nitrox provides the diver with an opportunity to increase bottom
times or reduce the risk of decompression illness by reducing the nitrogen con-
tent in the breathing gas mix.

11
However, when the gas mix is altered, the oxygen content of the mix is generally
increased. This increase exposes the diver to an oxygen toxicity risk not usually
considered in recreational diving. In order to manage this risk, the dive compu-
ter tracks the time and intensity of the oxygen exposure and provides the diver
with information to adjust the dive plan in order to maintain oxygen exposure
within reasonably safe limits.
In addition to the physiological effects of enriched air on the body there are
operational considerations to be addressed when handling altered breathing mixes.
Elevated concentrations of oxygen present a fire or explosion hazard. Consult
the manufacturer of your equipment in regards to its compatibility with nitrox.

12
2. GETTING ACQUAINTED
2.1. FUNCTIONS
The Suunto GEKKO can be set to function as a regular air dive computer or as a
nitrox dive computer.
The GEKKO features two dive computer models (AIR, NITROX), three main
operating modes (TIME/STAND-BY, SURFACE, DIVING), two menu based
main modes (MEMORY, SET) and seven menu based submodes (review sepa-
rate Quick Reference Guide). You can scroll through the modes using the push
buttons. The mode indicator at the left side and the mode text at the bottom of
the display indicate the selected mode.
The timekeeping display is the default display of the instrument (Fig. 2.1.). If a
button is not pressed within 5 minutes, the dive computer beeps and returns to
the timekeeping display automatically (except in Diving mode). The timekeep-
ing display shuts off after two hours, but pressing the PLAN or TIME button
activates it.
Making the GEKKO Personal
For best use of the GEKKO take some time and make
it YOUR computer.
Set the correct time and date. Read this manual. Set
dive alarms and make all the other settings listed in
the introduction in this manual. Install the GEKKO
in your console or fit it on to your wrist.
All this so you know your computer and have it set
up as you want it before getting into the water.
2.2. PUSH BUTTONS
The GEKKO has easy-to-use push buttons and an
advisory display, which guides the user. The
SMART (MODE) button is the key to the system.
The two scroll buttons, PLAN and TIME, are used
for scrolling up and down the menus and to show
the alternative displays. The dive computer is con-
trolled with these three push buttons as follows (see
Fig. 2.2.).
Fig. 2.1. Timekeeping
display. Pressing PLAN or
TIME button activates
display.
Fig. 2.2. Push buttons of the
dive computer.
The SMART button
The PLAN, TIME and
SCROLL buttons

13
Press the SMART (MODE) button
•To activate the dive computer.
•To change from the Surface Mode to the
menu based modes.
•To select, confirm or quit a submode (short
press).
•To immediately exit any submode to the
Surface Mode (long press).
Press the arrow up scroll (PLAN) button
•To activate the timekeeping display, if the
display is blank.
•To activate the Dive Planning in the Surface
Mode.
•To make a special bookmark in the profile
memory during a dive.
•To scroll up the options (L, increase).
Press the arrow down scroll (ALTER) button
•To activate the timekeeping display, if the
display is blank.
•To activate the alternative display(s).
•To scroll down the options (M, decrease).
The dive computer is controlled with the SMART
(MODE/On/Select/OK/Quit) and the PLAN Land
TIME Mpush buttons and with the water contacts
as follows:
Activation press the SMART (On) button
or immerse the instrument
in water for five (5) seconds.
Dive
Planning in the Surface Mode, press the PLAN
(s) button.
Menu Modes press the SMART (MODE) button.

14
2.3. WATER CONTACTS
The water contacts control the automatic activation
of the Dive Mode.
The water and data transfer contacts are located on
bottom of the case (Fig 2.3). When submerged the
water contacts are connected to the push buttons
(which are the other pole of the water contact) by
the conductivity of the water. The “AC”text (Ac-
tive Contacts, Fig. 2.4.) will appear on display. The
AC text will be shown until the water contact deac-
tivates or the dive computer enters the Dive Mode
automatically.
Fig. 2.4. Active water
contacts are indicated by the
text AC.
Fig 2.3. Depth sensor (A),
water/data transfer contacts
(B).
C
L
O
S
E
O
P
E
N
A
B

15
3. DIVING WITH THE GEKKO
This section contains instructions on how to oper-
ate the dive computer and interpret its displays. You
will find that this dive computer is easy to use and
read. Each display shows only the data relevant to
that specific diving situation.
3.1 BEFORE DIVING
3.1.1. Activation and Prechecks
The dive computer will activate if submerged deep-
er than 0.5 m (1.5 ft). However, it is necessary to
turn on the Dive Mode before diving to check the
altitude and personal adjustment settings, battery
condition, oxygen settings etc. Press the SMART
(Mode) button to activate the instrument.
After activation all display elements will turn on
showing mostly figure 8’s and graphical elements
(Fig. 3.1.). A few seconds later the battery power
indicator is shown and the buzzer is activated (Fig.
3.2. display a, b, c or d depending on the battery
voltage). If set to Air mode the screen will enter the
Surface mode (Fig. 3.3.) and if set to Nitrox mode
the essential oxygen parameters are shown with the
text NITROX (Fig. 3.20.) before the Surface mode.
Fig. 3.1. Startup I. All
segments shown.
Fig. 3.2. Startup II. Battery
power indicator.
° F
°C
ft
MAXAVGPO
NO DEC TIME
STOP
TIME
TIME
SURF
DIVE
O %
ASC TIME
CEILING
OK
QUIT
SELECT
OPTIONS
NO
S
L
O
W
T
C
B
OLF
DIVE
m
QUIT
OK

16
At this time, perform your prechecks making sure
that:
•the instrument operates in the correct mode
and provides a complete display (Air/
Nitrox modes)
•the low battery indicator is not on
•the altitude and personal adjustment
settings are correct
•the instrument displays correct units of
measurement (Metric/Imperial)
•the instrument displays correct temperature
and depth (0.0 m [0 ft])
•the buzzer beeps
And if set to Nitrox mode (refer to chapter 3.4 Div-
ing in Nitrox mode), make sure that:
•the oxygen percentage is adjusted accord-
ing to the measured Nitrox blend in your
cylinder
•the oxygen partial pressure limit is set
correctly.
The dive computer is now ready for diving.
Fig. 3.4. Low Battery
Warning. Battery symbol
indicates that the battery is
low and battery replacement
is recommended.
Fig 3.3. Startup III. Surface
mode. Depth and dive time
are zero, current
temperature, 20 °C. Pressing
TIME button activates
alternative display of current
time.
TIME
DIVE
m
TIME
° C
TIME
DIVE
m
° C
Fig. 3.5. Dive Planning.
Planning mode is indicated
by PLAN text. No-
decompression time limit at
30.0 m [100 ft] is 14 minutes
in A0/P1 mode.
QUIT
DIVE
NO DEC TIME
MAX

17
3.1.2. BATTERY INDICATION
3.1.2.1. Battery Power Indicator
This dive computer has a unique graphic Battery Power Indicator designed to
give you an advance notice of impending need to change the battery.
The Battery Power Indicator can always be seen when the Dive Mode is activat-
ed. The following Table and Figure show the various warning levels.
Display Operation Figure 3.2
BAT + Normal, full battery. a
4 segments + OK
BAT + Normal, battery power is getting b
3 segments low or the temperature is low.
Battery replacement is recommended
if you are going to colder conditions
or if you are planning to make a dive trip.
LOWBAT + Battery power is low and the battery c
2 segments + replacement is recommended.
low battery symbol The battery symbol is displayed.
LOWBAT + Change the battery! d
1 segment + QUIT+ Returns to the Time display.
low battery symbol Activation and all functions are disabled.
TABLE 3.1. BATTERY POWER INDICATOR
Temperature or an internal oxidation of the battery affects the battery voltage. If
the instrument is stored for a long period, the low battery warning may be dis-
played even though the battery has enough capacity. The low battery warning
may also be displayed at low temperatures, even though the battery has enough
capacity in warmer conditions. In these cases repeat the battery check proce-
dure.
After battery check the Low Battery Warning is indicated by the battery symbol
(Fig. 3.4.).
If the battery symbol is displayed in the Surface mode or if the display is faded
or weak, the battery may be too low to operate the dive computer and battery
replacement is recommended.

18
3.1.3. Dive Planning [PLAN]
To enter Planning Mode, press the PLAN button at any time during Surface
Mode. After showing the text “PLAN”(Fig. 3.5.), the display will show the no-
decompression limit for the depth of 9 m [30 ft]. By pressing the down arrow
(M) (TIME) button, the dive computer will calculate and show the next deeper
no-decompression limits in 3 m [10 ft] increments ending at 45 m [150 ft]. By
pressing the up arrow (L) (PLAN) button, the next shallower depth will be shown
again.
The Planning Mode is canceled by pressing the SMART (QUIT) button.
NOTE! The Planning mode is disabled in Error mode (see section 3.8. “Error
Conditions”).
Higher Altitude and conservative Personal Adjustment Modes will shorten the
no-decompression time limits. These limits at different Altitude and Personal
Adjustment Mode selections are shown in Table 6.1 and 6.2 in section 6.1. “Op-
erating Principles”.
The Planning mode also accounts for the following information from previous
dives:
•any calculated residual nitrogen
•all dive history for the past four days
•oxygen toxicity (Nitrox mode)
The no-decompression times given for different depths will therefore be shorter
than before your first “fresh”dive.
DIVE NUMBERING SHOWN DURING DIVE PLANNING
Dives belong to the same repetitive dive series if the instrument was still count-
ing down the no-fly time at the beginning of the dive.
The surface interval must be at least 5 minutes for a dive to be considered a
repetitive dive. Otherwise, it is considered a continuation of the same dive. The
dive number will not change and the dive time will continue where it left off (see
also section 3.5.2. “Dive Numbering”).

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3.1.4. User Definable Functions and Alarms
The GEKKO has several user definable functions and depth and time related
alarms that you can set according to your personal preference.
The dive computer model (Air/Nitrox) can be set in the MODE- SET- MODEL
submode. The dive alarms can be set under MODE- SET- SET ALARMS, the
time and date settings in MODE-SET-SET TIME, and the units (metric/imperi-
al) as well as personal adjustments in the MODE- SET- SET ADJUSTMETS
submode. Setting of the user definable functions and alarms are explained in
detail in section 4.2. “Set Modes”.
3.2. SAFETY STOPS
Safety stops are widely considered “good diving practice”and are an integral part of
most dive tables. Reasons to perform a safety stop include a reduction in sub clinical
DCI, microbubble reduction, ascent control, and orientation before surfacing.
The GEKKO displays two different types of safety stops: Recommended Safety
Stop and Mandatory Safety Stop.
The Safety Stops are indicated by:
- STOP label, when in the depth range 3 m - 6 m [10 ft - 20 ft] =
Recommended Safety Stop Countdown
- STOP+ CEILING label, when in the depth range 3 m - 6 m [10 ft - 20 ft] =
Mandatory Safety Stop Time display
- STOP label, when deeper than 6 m = Mandatory Safety Stop scheduled
3.2.1. Recommended Safety Stop
With every dive over 10 meters the instrument has a three minute countdown for
the recommended safety stop, to be taken in the 3 - 6 meter [10 ft - 20 ft] range.
This is shown with the STOP sign and a three-minute countdown in the center
window instead of the no-decompression time (Fig. 3.9.).
The Recommended Safety Stop, as the name implies, is recommended. If it is
ignored, there is no penalty applied to the following surface intervals and dives.
3.2.2. Mandatory Safety Stop
When the ascent rate exceeds 12 meters/min [40 ft] momentarily or 10 meters/
min [33ft] continuously the micro-bubble build-up is predicted to be more than
allowed for in the decompression model. The Suunto RGBM calculation model
responds to this by adding a Mandatory Safety Stop to the dive. The time of this