As a safety measure, it is recommended when using dive tables to plan for depths beyond your planned depth. You should write these calculations down on a slate and have them available on the dive. If the planned depth is accidentally exceeded, you can refer to the slate. You can find out what the adjusted allowable dive time is for the new depth. Note: Do not plan to dive deeper. This step is designed to help you in case you accidentally exceed your planned depth .
If using a dive computer, you do not need to worry about the calculation of the NDL because this is completed by the computer. The dive computer calculates the allowable dive time every 2 or 3 seconds while underwater. Although the dive computer does calculations underwater, it is still recommended to plan the dive on your dive computer beforehand. You need to determine what the limiting factor will be and which limit may be the first to consider: Will it be the NDL or the gas supply?
The dive computer has a few limitations.
- The dive computer will not be able to account for the gas supply unless the computer has a high-pressure sensor link.
- The dive computer will not be able to account for previously completed dives that the computer has not logged.
- Dive computers cannot account for the tissue loading of another diver. It must be used by only the same person within 24 hours.
- It is recommended not to use any dive computer that has not cleared from the no-fly time and/or has a dive log history within 24 hours of your use.
- Dive computers (and dive tables) do not consider your individual physical diving fitness and hydration levels.
Note: You may dive many times a day, provided you dive within the limitations of all the factors and stay within the NDL limits.