Shearwater TERN - Page 21

Operating Instructions
Page 21
Doc. 15301-RevB (2023-11-24)
Home screen only info displays
Some advanced info displays are only available as
custom home screen options and not in the info rows�
Surface GF
The surfacing gradient
factor expected if the diver
instantaneously surfaced�
SurfGF colour is based on the current GF (GF99)� If
the current GF is greater than GF High, SurfGF will be
displayed in Yellow� If the current gradient factor is
greater than 100%, SurfGF will be displayed in Red.
Ceiling
The current decompression ceiling
not rounded to the next deeper
stop increment� (i�e� not a multiple
of 10ft or 3m)
@+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�
Δ+5
The predicted change in TTS if you
were to stay at the current depth
for 5 more minutes�
A positive “Delta plus 5” indicates that you are on-
gassing the leading tissue while a negative number
indicates that you are off-gassing the leading tissue�
m
min
GF
35/75
GF99
22
%
15
TTS
SURFACE
m
min
Δ+5
+8
@+5
20
CEIL
8
SURFACE
m
min
Δ+5
+8
@+5
20
CEIL
26
SURFACE
m
min
Δ+5
+8
@+5
20
CEIL
26
SURFACE
Gas Density Display
The current gas density based on
the current active gas and ambient
pressure�
The gas density display turns yellow
at 6�3 grams per liter� No other
warnings are generated�
If you are a technical diver, you may be surprised at
how shallow this warning colour appears�
Read more about why we chose this warning level
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.
DensityCNS
%
11
m
min
PPO2
.211.3
g/L
SURFACE
DensityCNS
%
11
m
min
PPO2
.216.4
g/L
SURFACE