This was also my experience in the Nuclear Navy, wholly disconnected from software development. I was my division’s maintenance planner, among other things, and so I needed to plan when we would accomplish preventative maintenance on approximately 20 different systems. Planning was usually done a quarter at a time, but there were semi-annual, annual, and greater maintenance items you also had to take into account. Further complicating things, many of the items had specific plant criteria to be met (some are easy, like “the reactor must be shut down”), some of which would only happen once in a given quarter at best. Finally, if you wanted to maximize efficiency, you also should carefully read every maintenance item to determine where there was crossover, so you could use one to partially setup for another.

I made a huge dependency table in Microsoft Project, and generated Gantt charts from that. It worked flawlessly. A few key differences on the people side compared to software:

* No one insisted that I plan for the nominal persons’ abilities. If Petty Officer Schmuckatelli happened to be a savant at a specific maintenance item, guess what, he’s always getting assigned that one. Others would assist (nuclear maintenance is always a two-person operation), but getting the job done correctly and efficiently was priority one.

* I didn’t have to get consensus from a team on how long everything should take. This one is of course quite different from software, in that a lot of software work is novel to an extent; on the other hand, my submarine was of a new class, so there wasn’t a lot of institutional knowledge to fall back on.

* Accountability is actually a thing. If you say something has been done, it’d damn well better be done. If you make a mistake, there is an all stop while you convene a meeting of god and country to hold a retrospective (though we call them critiques). There will be consequences. Not career-ending or anything – it’s quite common to cause a critique or three – but you also don’t get to just skip on out. They’re not blameful in that the point isn’t simply to say, “why do you suck,” but they’re also not oblivious to the fact that often, a person’s inattentiveness is in fact the root cause.