When an actual depth falls between two planned depth schedules, select the deeper schedule on the bottom time (BT) table.
For example, if the dive will have a 65-foot depth, then determine the bottom time from the 70-foot schedule. The deeper schedule increases the margin of safety.
A common mistake is applying the next deeper schedule rule to the Residual Nitrogen Time (RNT) table when determining the RNT deduction from the bottom time for the repetitive dive. The proper action when determining the RNT is to use the next shallower schedule.
When an actual depth falls between two planned depth schedules, select the shallower schedule on the Residual Nitrogen Time (RNT) table.
For example, if the dive will have a 65-foot depth, then determine the Residual Nitrogen Time from the 60-foot schedule. The shallower schedule increases the RNT deduction from bottom time, increasing the margin of safety.