Did you ever hear of the Rule of Thirds? This is part of the scuba safety training with our YMCA scuba program. Cave and wreck divers know this rule very well. The rule is a life saving technique.

The Rule of Thirds is based on the fact the most scuba tanks have about 3000 psi. Using the rule will keep a diver from running out of air. The rule follows the principle of going out for 1000 psi, then coming back to the boat using another 1000 psi. Now the diver should have about 500 psi (most dive boats want you aboard with 500 psi) to explore around the boat and do a safety stop. It also means working together with your buddy. Buddies need to agree that the 1st diver to use 1000 psi means you both have to turn around and start back. While it may reduce bottom time a little, the Rule of Thirds can be life saving.