It is limited only by the amount of air in the tanks and is based on the need to fill a sack with sea cucumbers. The switch-over to the reserve tank is normally the signal to ascend. Divers then re-surface as quickly as possible, with no intermediate stages. The amount of effort needed to re-surface is often increased by the need to heave up a sack containing sea cucumbers. Divers do not use diving tables, watches, or depth gauges, as these are not included in their equipment.
Depth is estimated by using a rope hanging from the boat.
The equipment is not maintained, diving tanks are never serviced and regulators are often defective. When equipment fails, divers make panic ascents. Each diver does at least two dives a day, and sometimes three or even four. Diving in pairs is unknown. Skin-diving is carried out at maximum depths of between 17 and 20 m, under the same physical conditions as scuba diving and without any mutual surveillance.