Bottom Timers show info...

A Bottom Timer makes a great backup to a dive computer. They record depth and time, but do no decompression calculations. Bottom Timers are typically used by technical divers and by others who are diving tables or using some other method for determining their decompression status.

Many technical divers use a dive computer, but also have a Bottom Timer as a backup should the dive computer be lost or fail. The divers will have planned the minimum deco and turn pressures for the planned dive on the surface, and simply switch to run their dive using these prepared tables and their Bottom Timer if they need to.

Some technical divers take the time to learn their dive tables and then dive safely using just a Bottom Timer. Without a reliance on dive computers and with the ability to calculate their own deco on the fly, they feel there is no need to use a dive computer. Plans are made in advance and with experience a dive team can learn to adjust these underwater as necessary.

Dedicated Bottom Timers have become quite expensive. Many technical divers now simply purchase a cheap dive computer with a gauge, or bottom timer. In this mode the dive computer doesn't perform any decompression calculations.