Bill ran the numbers and decided he could break one of tech diving's cardinal rules of safety. The numbers didn't lie, but they also didn't account for an unplanned emergency.

A series of avoidable mistakes claims the lives of two divers.

A close call drills important safety lessons into the head of one lucky diver. Next time, he'll follow instructions. After reading his story, you will too.

Ill-prepared for ocean currents, an out-of-shape diver panics with fatal results.

Two divers follow a divemaster beyond the level of their training. Only one comes back.

Two lobster divers ascend from a dive to find their boat is nowhere in sight.

A technical buddy team ignores their training, and one diver pays the price.

Adhering to predive procedures is crucial when using a closed-circuit rebreather. Without a buddy to catch his mistake, one diver pays the ultimate price for carelessness.

At the surface, two divers caught in a current watch helplessly as their unmanned sailboat becomes a speck on the horizon. Learn how you can avoid making their mistakes.