The two aren’t very closely related except that they take place in the water. In sport your are taught to be reliant on your buddy and gear dependent. In the military you learn to be self reliant and not dependent on your gear.
In the Navy we were taught to do both free and buoyant assents from 119’. We didn’t just learn the theory but actually practiced it dozens of times.
You learn that SCUBA is a container of air and a way to get it into your lungs. It may not mean a regulator and just might be the valve but “EVERYTHING” else is optional.
Sure you are taught to dive with a buddy but should that buddy not be there it’s no big deal and you don’t need to abort a dive.
There are many, many differences. Some sport divers don’t like military diving saying it is job specific. Sure it is but so is sport diving. In the military you learn to be self-sufficient and do a wide variety of jobs and operations under a very wide variety of conditions. In sport you learn to stay next to your buddy and look at the scenery under more ideal conditions.
For example, Sport Rescue classes are reported over and over to be a very tough class by most who take it. In the military a tough Sport Rescue class would be a very easy day of training.
Trust me when I say they have very little in common. When I got out of the Navy I thought I wanted to be an instructor. That was until I went through the first two classes.
For those thinking about joining the military diving ranks it is best to just stay quiet about your diving exploits. I had been to Navy Scuba School prior to Second Class School. That in itself was not a good thing. Already being a Navy Scuba diver and repeating scuba in Second Class School I was the class whipping post and poster boy. If I made the slightest mistake it was blown up like Mt. St. Hellens.
Attitude plays a big part. If it gets bad you can even be washed out on graduation day which I have seen happen.
I would have not traded that training for anything.
Gary D.