Goats find the weak spot. Water does too.

I keep goats. Five of them, on six acres in central Virginia. A goat does not test the strong part of a fence. It walks the whole line, every day, and it finds the one section you meant to fix in spring and didn’t. The fence isn’t as good as its average. It’s as good as its worst foot.

This sounds like a saying. It isn’t. It’s a description of what goats actually do — methodically, constantly, without any agenda other than the next interesting thing — and the consequence is that you can’t fence-by-average. You can fence by sections and still lose the herd through the one post you walked past in March because the ground was still frozen and you told yourself you’d come back in April.

Diving rewards the same kind of attention and punishes the same kind of averaging.

The check you didn’t do

A pre-dive check done as a rhythm is easy to perform without actually performing it. Tank — yes. Weights — yes. Releases — yes. Air on, regulator breathes, gauge reads. Final OK, hand signal, step off the platform. Five seconds of touch and confirmation, and the last hundred times every box was already ticked before your hand got there.

That’s the averaging. That’s the post you walked past.

What it usually finds

Almost never the dramatic thing. The dramatic thing — first-stage failure, regulator free-flow, BCD inflator stuck open — announces itself. You hear it. The boat hears it. Somebody fixes it on deck or the dive doesn’t happen.

The thing the dive actually finds is small. The SPG hose o-ring is the house example, and it deserves the spot. A tiny rubber ring at the high-pressure connection where your console mounts to the first stage. It looks fine when you check it on the boat — they almost always look fine on the boat. Then you do the giant stride, the pressure changes, and it weeps. Not a catastrophic failure. A slow stream of bubbles from your console hose for the next forty-five minutes, and air loss you have to keep tracking because the gauge is the thing that’s leaking.

The dive doesn’t care that the rest of the check was good. It finds the one foot you skipped.

You knew the o-ring was probably fine. You knew the connection has been on that hose for years and never given anyone trouble. That’s exactly the post the goat finds.

The goat fix

The goat fix is not a better fence. It’s walking the line and putting your hand on the post you’d rather assume is solid. You don’t argue with the post. You don’t decide whether it deserves the attention. You touch it, you wiggle it, you look at the soil around the base. Then you move on.

The dive version is the same. On your next pre-dive check, slow down on the one step you’re surest about. Not because you suspect it’s broken — you don’t, and it probably isn’t. Slow down because that’s the step where your hand reports back “fine” without actually looking. The look is the entire fix.

For most divers that’s the o-ring at the SPG connection. Or the BCD inflator button you’ve used a thousand times. Or the weights, which you’ve never had ditch on you, so you’ve stopped really checking they’re seated. Pick the one that’s yours.

Then on the actual dive, find out what your check missed. There’ll be something. The goats taught me to expect it.