Shearwater TERN - Decompression Stops

Operating Instructions
Page 25
Doc. 15301-RevB (2023-11-24)
4.2. Decompression Stops
Decompression stops are mandatory stops that
must be followed in order to reduce the risk of
decompression illness (DCI)
Decompression stops occur at fixed 10ft (3m)
intervals�
Decompression stops display as follows:
Replaces NDL
Once the NDL reaches zero, deco
stop information will replace it on
the left side of the Deco Row in the
Standard layout, or the left side of the
info row home screen in the Big layout�
On the Tern, the deco stop label appears in red
because a deco obligation is an emergency condition
in recreational diving�
Deco Stops Required
An alert will indicate when
Deco Stops are required� This
must be cleared manually�
Do not dive beyond your training
Only perform decompression diving if you have
received proper training to do so�
Diving with any type of overhead ceiling,
whether in a cave or shipwreck, or from a
decompression requirement, adds significant
risk� Have a plan to handle failures and never
rely solely on a single source of information�
Deco Stop Violation
If you ascend shallower than a
deco stop, but remain deeper
than your current ceiling, stop
info will display in yellow�
If you ascend shallower than
your current ceiling, the display
will flash red� Significant
stop violations will result in a
“MISSED STOP” alert�
Deco Stops Complete
Once all decompression stops
are complete, the safety stop
will begin counting down, or,
if enabled, the Deco Clear counter will begin counting
up from zero�
If safety stops are turned off, the display will say
“Clear”�
There is no lock-out or other penalty for
violating decompression stops�
The policy is to provide clear warnings that
the decompression scheduled was violated,
to allow you to make decisions based on your
training�
This may include contacting your dive
insurance provider, contacting the nearest
recompression chamber, or performing first aid
based on your training�
No Lockout for violating Deco Stops
ft
125
.
6
O2/He
21/00
PPO2
.21
TTS
OC
SURFACE
mh
3412
C
L
E
A
R
WARNING
Deco Needed
NDL
21 21
ft
125
.
6
O2/He
21/00
PPO2
.21
TTS
OC
SURFACE
mh
3412
C
L
E
A
R
INFO
Deco Clear
NDL
21 21
125
15 2
O2/He
m min
DECO
125
O2/He
m min
DECO
15 2
125
DECO
15 2
O2/He
m min
ft
125
.
6
O2/He
21/00
PPO2
.21
TTS
OC
SURFACE
mh
3412
C
L
E
A
R
WARNING
MISSED STOP
NDL
21 21