Garmin Descent Mk2 / Mk2S setup guide

Also covers: Garmin Descent Mk2, Descent Mk2S

Five-button dive watch (LIGHT, UP·MENU, DOWN, START·STOP, BACK·LAP) with Single-Gas, Multi-Gas, CCR, Gauge, Apnea and Apnea Hunt modes. Rechargeable; tone and vibration alerts. The Mk2i has its own manual and is not covered here.

Buttons

Button	Where	What it does
`LIGHT`	left side, top	Turn on; backlight; hold for the controls menu (power off)
`UP·MENU`	left side, middle	Scroll; hold to open the main settings menu
`DOWN`	left side, bottom	Scroll; during a dive, step through the data screens
`START·STOP`	right side, top	Open the activity/dive list; choose a menu option; during a dive, open the dive menu
`BACK·LAP`	right side, bottom	Go back; hold to return to the watch face

Turn on / wake

Press LIGHT to turn the watch on. On first use, follow the on-screen setup and charge it.
PressLIGHT
Manual p. 7
Use UP and DOWN to scroll, START to choose an option and BACK to go back. Hold BACK to return to the watch face.
PressUP·MENUPressDOWNPressSTART·STOPPressBACK·LAP
Manual p. 7–8
Hold MENU (the UP button) to open the settings menu, where Dive Setup and System are found.
HoldUP·MENU
Manual p. 7–8
To turn the watch off, hold LIGHT to open the controls menu, scroll with UP or DOWN, and select the option to turn the watch off.
HoldLIGHTPressUP·MENUPressDOWNPressSTART·STOP
Manual p. 8
During a dive, hold functions do not work; press START to open the dive menu and BACK to leave it.
PressSTART·STOPPressBACK·LAP
Manual p. 7–8

Date and time

The manual describes no separate manual date entry; the date comes from the GPS or phone sync.

The watch sets the time and time zone itself when it gets GPS satellites or syncs with the paired phone app.
Manual p. 112
To change the format, hold MENU and select System > Time > Time Format (12-hour, 24-hour or military).
HoldUP·MENUPressSTART·STOP
Manual p. 111
To set the time by hand, set Set Time to Manual, then use Time to adjust it.
PressSTART·STOP
Manual p. 111
After travel or for daylight saving time, use the sync option in System > Time to update the clock.
PressSTART·STOP
Manual p. 112

Units (m/ft, °C/°F)

Hold MENU and select Dive Setup > Units to set distance, depth and tank pressure units for diving.
HoldUP·MENUPressSTART·STOP
Manual p. 12
For other units, including temperature, hold MENU and select System > Units, select a measurement type, then the unit.
HoldUP·MENUPressSTART·STOP
Manual p. 112

Water type (salt/fresh)

The manual does not list the water type options; choose the one shown for your dive site. It also affects the gas calculator (p. 23).

Hold MENU and select Dive Setup > Water Type.
HoldUP·MENUPressSTART·STOP
Manual p. 12
Select the water type that matches your dive site.
PressSTART·STOP
Manual p. 12
You can also change it on the pre-dive screen: after choosing the dive mode, press DOWN to edit the dive settings.
PressDOWN
Manual p. 19

Dive mode (Air / Nitrox / Gauge)

From the watch face, press START and select a dive mode: Single-Gas, Multi-Gas, CCR, Gauge, Apnea or Apnea Hunt.
PressSTART·STOP
Manual p. 19
For one tank of air or nitrox choose Single-Gas. Gauge is a bottom timer only.
Manual p. 11–12
Press START until the main dive screen appears, then descend. The dive starts at 1.2 m (4 ft).
PressSTART·STOP
Manual p. 19
If you dive without choosing, the watch uses the last dive mode and its settings.
Manual p. 19
After a Gauge dive, only Gauge or Apnea mode can be used for 24 hours.
Manual p. 11–12
If you stay above a deco ceiling for more than 3 minutes, deco lockout blocks gas dives for 24 hours. Keep Deco Lockout on.
Manual p. 12

Nitrox O₂% and ppO₂ limit

The manual gives no default PO2 values and does not say that the O2 % resets by itself.

Hold MENU and select Dive Setup > Gases, then select the dive mode (Single-Gas).
HoldUP·MENUPressSTART·STOP
Manual p. 12
Select the first gas in the list (the bottom gas).
PressSTART·STOP
Manual p. 13
Select Oxygen and enter the O2 % of your analysed tank.
PressSTART·STOP
Manual p. 13
Select Helium and enter the helium %. For nitrox (no helium) this is 0. Press BACK when done.
PressSTART·STOPPressBACK·LAP
Manual p. 13
Set the MOD limit: Hold MENU, select Dive Setup > PO2 > MOD/Deco PO2, and enter the value your instructor gives you.
HoldUP·MENUPressSTART·STOP
Manual p. 14
PO2 Warning and PO2 Critical in the same menu set when the watch warns about high oxygen.
PressSTART·STOP
Manual p. 14

Conservatism / personal setting

The manual does not list the preset level names or values; check the choice on screen with your instructor.

Hold MENU and select Dive Setup > Conservatism, then choose a level.
HoldUP·MENUPressSTART·STOP
Manual p. 12
Higher conservatism gives shorter bottom times and longer ascents.
Manual p. 12
The Custom option lets you enter your own gradient factors. Do not use it unless you understand them.
Manual p. 12

Altitude

Not available on this computer

There is no altitude setting: the watch adjusts for altitude automatically with its barometric pressure sensor (p. 24).

Audible alarms (depth / time)

Hold MENU and select Dive Setup > Scuba Alerts.
HoldUP·MENUPressSTART·STOP
Manual p. 13
Select Add Alert, or select an existing alert to edit it, and turn it on.
PressSTART·STOP
Manual p. 13
For a Depth alert set the depth; for a Time alert set the time.
PressSTART·STOP
Manual p. 13
Select Sounds to choose a tone, vibration, or neither. Use Preview Alert to hear and see it.
PressSTART·STOP
Manual p. 14
Keep Silent Diving turned off; when on, it stops all tones and vibration during dives.
Manual p. 12
Built-in warnings include Approaching NDL (at 10 and 5 minutes left) and ascending faster than 9.1 m (30 ft) per minute.
Manual p. 25

Reading the log after a dive

From the watch face, press UP or DOWN to the dive log widget.
PressUP·MENUPressDOWN
Manual p. 23
Press START to see your most recent dive. To pick another dive, press DOWN, then START.
PressSTART·STOPPressDOWN
Manual p. 23
Press START and choose All Stats for the full details, or the depth and temperature graphs.
PressSTART·STOP
Manual p. 23
The surface interval widget shows CNS %, OTU, tissue load and no-fly time.
PressUP·MENUPressDOWN
Manual p. 22–23

Battery

To charge, pinch the charging clip, line it up with the contacts on the back and release, then plug in the USB cable. The screen shows the charge level.
Manual p. 10
Clean and dry the contacts before charging to prevent corrosion.
Manual p. 10
On the pre-dive screen, Battery is low appears below 20% and Battery critically low below 10%. Charge before diving.
Manual p. 25
During a dive, the customizable data screen (press DOWN) shows the battery level.
PressDOWN
Manual p. 15

What the main screen shows

The main dive screen shows your breathing gas, PO2 and ascent or descent rate. Press DOWN or double-tap the watch for more screens and the dive compass.
PressDOWN
Manual p. 15
Ascent rate colours: green below 7.9 m (26 ft) per minute, yellow up to 10.1 m (33 ft), red above that.
Manual p. 15
Tissue load: green 0–79%, yellow 80–99%, red 100% or more.
Manual p. 15
After a dive of at least 11 m (35 ft), ascend to 5 m (15 ft): the safety stop timer counts down when you are within 1 m (5 ft) of the stop depth.
Manual p. 21
If deco is needed, the stop depth and timer appear. Stay within 0.6 m (2 ft) of the stop until it clears.
Manual p. 22
At the surface the dive ends after the End Dive Delay, or press START and select Stop Dive.
PressSTART·STOP
Manual p. 19

Pre-dive check

Tick each item before you get in the water.

Correct dive mode chosen on the pre-dive screen (Single-Gas for air or one nitrox).
Bottom gas O2 % matches your analysed tank.
MOD/Deco PO2 is the value your instructor gave you.
Water type matches the dive site.
Conservatism is the level your instructor wants.
Depth and time alerts set; Silent Diving off.
No low-battery message on the pre-dive screen (charge above 20%).
Deco Lockout is on and no lockout is active.