Diving Terms Used by this Watch
The following provides an explanation of the diving terms displayed by this watch along
with their basic meanings.
<Algorithm>
This watch employs the calculation formula of the Canadian Defense and Civil Institute of
Environmental Medicine (DCIEM).
<Scuba Diving and Skin Diving>
This watch automatically distinguishes between skin diving and scuba diving according to
the following conditions, and records log data separately for each type of diving.
• Scuba diving: Continuously diving for 3 minutes or more to a depth of 1 m (4 ft) or more
• Skin diving: Continuously diving for less than 3 minutes to a depth of 1 m (4 ft) or more
<One Dive>
In this watch, one dive constitutes the time from initially diving to a depth of 1 m (4 ft) (start
of dive) from the preliminary dive mode state to the time the dive mode is terminated (end
of dive).
<No-Decompression Diving and No-Decompression Limit (NDL) Time>
No-decompression diving refers to diving that allows the diver to ascend to the surface
without stopping for decompression during the course of ascending following completion
of a dive. The limit time during which this no-decompression diving is allowed is referred
to as the no-decompression limit time. No-decompression limit time varies according to
the diving depth and diving time of the previous dives.
<Safety Stop>
Safety stop refers to a temporary stop made during ascending for safety reasons in order
to promote expulsion of nitrogen in the body, and is performed even if the no-
decompression limit time has not been exceeded. In the case of having dove to a depth of
18 m (60 ft) or more, a safety stop should always be made at 5 m (15 ft) of depth to
ensure safety.
<Decompression Diving>
This refers to diving beyond the no-decompression limit time. Decompression diving is
extremely dangerous since nitrogen accumulates in the body beyond allowable levels.
Never dive in this manner.
<Decompression Stop>
This refers to a stop that must be made to ensure the necessary decompression in the
case of having performed decompression diving. It is necessary to make a
decompression stop at a predetermined depth (decompression stop instructed depth) and
predetermined time (decompression stop instructed time) when ascending.
<Total Ascending Time>
This refers to the minimum time required to ascend to the surface from the current depth in
the case of ascending at the rate of 18 m (60 ft)/min or less while making a decompression
stop in accordance with the decompression stop instructions during decompression diving.
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