Safety stops are widely considered good diving practice and are a critical part of most dive tables. The reasons for performing a safety stop include: reducing sub-clinical DCI, microbubble reduction, ascent control, and orientation before surfacing.
Suunto D4i displays two different types of safety stops: recommended and mandatory.
With every dive over 10 meters (30 feet), there is a three-minute countdown for the recommended safety stop. This stop is taken in the 3-6 m (10-20 ft) range. Suunto D4i shows a STOP icon and a three-minute countdown.
When deepstops are enabled, the length of mandatory safety stops is indicated in seconds.
When the ascent rate exceeds 10 m (33 ft) per minute for more than five consecutive seconds, the microbubble build-up may be more than is allowed for in the decompression model.
In this situation, Suunto D4i adds a mandatory safety stop to the dive. The time of this stop depends on the speed violation of the ascent rate.
The STOP icon is shown in the display. When you reach the depth zone between 6 m and 3 m (18 ft and 9 ft) the following is displayed:
Wait at the ceiling until the mandatory safety stop warning disappears.
NEVER ASCEND ABOVE THE CEILING! You must not ascend above the ceiling during your decompression. In order to avoid doing so by accident, you should stay somewhat below the ceiling.
Deepstops activate when you dive deeper than 20 m (65.6 ft).
If the dive timer is on the screen when deepstop activates, the timer is replaced with deepstop.
After deepstop is over, the user can change between deepstop and the timer by long pressing the MODE button.
Deepstops are presented the same way as safety stops. Suunto D4i notifies you that you are in the deepstop area by displaying:
Deepstop is on by default in Air and Nitrox modes. To turn deepstop off: