As most of you know, I hold the Guinness Word Record for the Deepest Dive by a Woman – which at first glance has nothing to do with Agile or Software Development. There are however some powerful parallels, not the least of which is how planning plays a role in success.

Diving for 6 hours plus to depths deeper than 200 meters isn’t a spur of the moment thing. It takes planning. There are risks that need to be managed, cylinders that need to be filled so that I have enough to breathe (and the right gas to breathe because you can’t use normal air to dive deeper than 50 meters). The saying goes that you plan the dive and then you dive the plan. You do not decided to add 5 minutes when you get to your end point or go deeper – those kinds of decisions tend to be fatal.

Having said that, an obsession with diving the plan can also be fatal if you do not notice when circumstances change. This was reinforced for me on one of my most memorable dives, a dive to 152 meters at Badgat, a flooded asbestos mine.

The dive was extreme for reasons other than its depth. To get deeper than 100 meters required a 3 minute swim at the lowest level (110 meters) and then following a narrow decline shaft for the next 50 meters. Alone! As in none of my support divers could reach me should something go wrong.

The dive petrified me. I had tried it a number of times and either turned back at the hole that is the entrance to the decline shaft or at 140 meters where the already narrow decline shaft got even narrower. However, doing this dive was the pre-requisite for getting to 221 meters and so the all-time depth record. It was the dive that would prove that I could manage the physiological effects of 221 meters.

So I steeled myself up and did it. I had my plan and I would not abort the dive unless the plan said so.

Just after the tunnel constricted (turns out at 152 meters) I suddenly stopped. Now the incline is such that is has about a foot of fine silt on the floor with huge wooden beams every 3 to 4 meters holding up the tunnel. I was following a thin white line laid along the right side of the tunnel. I remember speeding up my descent when I reached the narrowing so that I could get to my planned 160 and then get out. When I suddenly stopped I still had that plan in my head. I was irritated that I had been stopped. I realised that my fin had gotten hooked on the guideline so I was reaching back to unhook it. Only I was not able to really reach my feet with all the gear I had on me. All this time I was breathing like a steam train and at 150 meters you simply do not have enough has to be taking a new breath every 20 seconds.

In my mind I was still focused on reaching 165 meters. And then I suddenly realised that this was no longer the dive I had planned and if I followed my dive plan I would die.

The goal was no longer 165 meters. As I adjusted I found myself worrying about overstaying my time which meant my decompression profile would be invalid and would that mean I would bend on the way out ? Then I found myself worrying about running out of gas. I must have already been stuck for over 2 minutes and was breathing like a steam train.

That was when I realised that the only goal was to get unstuck. Everything else was a problem to be resolved when I could move again. It didn’t matter how long I was over staying or how much gas I had left to breathe, it only mattered to get moving. I did, by removing my fin which left me with the problem of swimming with one fin on next to no gas for the ascent back to 110 meters and then the longest, most tiring 3 minute swim I have ever done (it took more like 5 min).

I had over 15 minutes of decompression to do and under 40 bar in each of my cylinders to do it with and it didn’t matter. I would breathe those cylinders until they were dry and only then would I move to my back up supply at 40 meters.

The point of this story is simply that we get so caught up in our plans that we often fail to notice when the situation changes and so fail to adjust the plan accordingly. I am not sure we even know what to look out for, what the signs are that we need to adjust our plan. In diving we always have 3 turn around criteria, we reach the planned depth, we reach the planned dive time or we reach our critical gas pressure which basically says that if we don’t leave now we won’t have enough gas to breathe to reach the surface.

We know these three criteria before we get in the water and they drive decision making – until they are no longer the most important aspects of the dive. I had a direct, simple feedback loop that told me that things were no longer going according to plan and even then, it took an effort to adapt to the change.

How do you know when your plan is no longer valid ? What are the aspects you need to be monitoring ? Are you so committed to the plan that you will follow it to the death ? Or do you have the ability to adapt to changes ?