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# The Blueprint still holds
- URL: https://www.techdiving.com.au/the-blueprint-still-holds/
- Published: 2026-09-30T05:40:23.000Z
- Updated: 2026-09-30T05:40:23.000Z
- Description: In 1979 Sheck Exley looked at why cave divers died and found the same few mistakes again and again. More than forty years later, his list still explains most accidents.
- Author: Tech Diving AU
- Tags: Safety, Cave, #Import 2026-09-30 15:24

In 1979 Sheck Exley published *Basic Cave Diving: A Blueprint for Survival*. It wasn't a training manual. It was an accident analysis: Exley read the reports of cave-diving deaths and sorted them by cause. The result was a short list of mistakes that kept killing people, and a matching list of rules.

The rules were simple enough to remember under stress, and most training agencies still teach some version of them. They apply well beyond caves. Wreck penetration, deep open-water diving and rebreather diving all have their own versions of the same failures.

## The original causes

Exley's analysis pointed to four recurring factors. A fifth, training, was added later, once it was clear that many of the dead had never been taught to dive in the environment that killed them.

**Training**

Divers without cave training, or diving beyond it, appear again and again in the reports.

**Guideline**

No continuous line to open water. Silt-outs and lost divers follow.

**Gas**

No defined reserve. Divers ran out on the way out, often while solving a problem.

**Depth**

Air at depths where narcosis wrecked judgement, and oxygen toxicity at the extremes.

**Lights**

A single light failing in total darkness.

## Why the list still works

Each rule targets a failure that can't be fixed once it's happening. If you lose the line in zero visibility, you can't go back and lay one. If you're out of gas at the far end of a cave, there's no reserve to find. The rules push the solution to the surface, before the dive, where you have time to think.

That's the pattern worth keeping in mind as you read debates elsewhere on this site. Divers argue about how much gas is enough, which decompression model to trust and who to dive with. Almost nobody argues that those questions shouldn't be answered before you get in the water.

## What has changed since 1979

The equipment and the gases have moved on. Helium mixes have largely replaced deep air, and rebreathers have introduced failure modes Exley never had to consider: hypoxia, hyperoxia and carbon dioxide build-up, often with no warning. Gas density, covered in its own article here, is a newer concern.

The structure of the rules has held, though. Modern rebreather accident reviews read like updates to the Blueprint: missed pre-dive checks, dives beyond training, inadequate bailout. The failures are new, but the causes are familiar.

## Using the list on your own dives

A useful habit is to run the five headings as a pre-dive check, even for dives outside caves.

- **Training.** Have I been trained for this environment, depth and equipment, and have I dived it recently?
- **Guideline or route.** Can I find my way back without visibility? On a wreck, where's my exit and what marks it?
- **Gas.** What are my turn pressures, and do they cover a failure at the furthest or deepest point?
- **Depth.** Is my gas right for the depth, for narcosis, oxygen and density?
- **Lights.** Do I have enough independent sources, with burn time for the whole dive?

None of this guarantees a safe dive. It does mean that when something goes wrong, you've already made the decisions that most often decide the outcome.