Diving organizations such as PADI® or NAUI provide certified recreational scuba divers with a dive table to determine how long a diver can stay underwater at a given depth, both for the initial and subsequent dives. The reason for the dive planner is to ensure that the amount of nitrogen your body absorbs during a dive remains within acceptable limits.

Dive tables do not tell you how much nitrogen has accumulated in your body after a dive; they simply tell you how long you can stay at a given depth without having to have a mandatory decompression stop.

Recreational dive tables come in the form of a plastic coated card, and for many recreational divers these cards are daunting and look very complicated. For example, the PADI® dive card has tables on both sides of the card, containing over a thousand numbers.

At Wolfram|Alpha we have removed the complexity of trying to read the NAUI and PADI® dive tables.

Recreational dive planner

For example, if you enter recreational dive planner into Wolfram|Alpha, you will see the planning data for your first dive of the day using a PADI® dive planner (you can select the link for a NAUI planner if you prefer). Your parameters for the first dive of the day are the actual dive time and dive depth (default values are 20 min at 45 ft). Wolfram|Alpha computes the maximum dive time for this depth as 80 min, determines that you your pressure group after the dive is “E”, and advises you whether a safety stop is necessary. Also shown is a schematic of your dive profile.

Note if you enter a dive time for your first dive of 70 min, Wolfram|Alpha computes that your pressure group will be “V”, and that now a safety stop at 15 ft for 3 min is required. The schematic of the dive profile now shows a safety stop as well.

Let us suppose that you want to do a subsequent dive after your initial dive at 45 ft for 20 min. Recall that your pressure group after that dive was “E”. Suppose for your second dive you would like to dive to 60 feet for a total dive time of 40 min. What are the consequences? Well, if you immediately begin your second dive without any surface time, Wolfram|Alpha computes that your planned dive will exceed your allowable dive time, and a mandatory decompression stop will be required. These details are shown in a schematic of your dive profile.

You can avoid the mandatory decompression stop by taking a rest between dives. If you enter a surface time of, say, 90 min, Wolfram|Alpha computes that your planned second dive can be undertaken without a safety stop. The process can be repeated for subsequent dives.

We welcome you try our dive planner the next time you’re planning a trip to a lake or a beach, and we would love to hear your comments, feedback, and suggestions about it.

1 Comment

This was one of the things that came to mind when a math teacher recently directed this wonderful website, more specifically the tissue compartments. I’m interested in the data behind the NAUI, PADI, and US Navy dive tables. It would be interesting to see the RGBM and VPM integrated into program, as strictly a visualization of course (i.e. no homebrew deco models).

Sincerely,

-Brandon F.

Posted by Brandon F. October 5, 2011 at 5:24 pm Reply
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