Successive Dives

When you plan more than one dive in a day, residual inert gas from the first dive affects the decompression requirements of subsequent dives. The DiveToolbox planner supports successive (repetitive) dive planning by letting you link a new dive to a previously saved plan and specify the surface interval between them.

Enabling successive dive mode

In the dive planner, enable the "This dive follows another" option. This reveals additional fields for configuring the link to your previous dive.

Configuring a successive dive

Once enabled, you need to provide two pieces of information:

1. Select the previous dive

Choose the previous dive from your list of saved dive plans. The planner reads the tissue compartment state at the end of that dive to determine how much residual nitrogen and helium remain in your body at the start of the surface interval.

2. Enter the surface interval

Specify the time between surfacing from the previous dive and starting the current one. Enter the interval in hours and minutes.

During the surface interval, the planner calculates off-gassing at surface pressure (adjusted for altitude if applicable). The longer the surface interval, the more inert gas is eliminated, and the less impact the previous dive has on your current plan.

Successive dive configuration showing the previous dive selector and the surface interval fields (hours and minutes). planner-successive-light.png / planner-successive-dark.png

How it affects your plan

When a previous dive is linked, the planner adjusts the current dive's calculations:

• Reduced NDL: No-decompression limits are shorter because tissue compartments start with residual gas loading.
• Earlier or deeper deco stops: If the current dive requires decompression, stops may begin earlier or last longer compared to the same dive planned in isolation.
• Higher gas consumption estimates: The overall runtime may increase due to additional deco stops, which means more gas is consumed.

The results panel clearly shows these adjusted values so you can compare them against a standalone dive plan.

Tissue state data required

The previous dive plan must have been saved with tissue state data for the successive dive calculation to work accurately. If the selected plan does not contain tissue data, the planner will not be able to compute residual gas loading and will notify you.

Tips for successive dive planning

• Plan the deepest dive first. Standard repetitive dive practice recommends doing the deepest dive of the day first, when tissue loading is at its lowest.
• Allow adequate surface intervals. A longer surface interval reduces residual loading and gives you more favorable NDLs and deco schedules on the next dive.
• Check gas consumption carefully. Successive dives often have longer runtimes due to increased deco obligations. Make sure your tank configuration provides enough gas for the adjusted plan.
• Chain multiple dives. You can plan a full day of diving by saving each plan in sequence; the second dive references the first, the third references the second, and so on. Each plan inherits the cumulative tissue state from all prior dives.