I just remembered why I kept the crew training level firmly set to 1. >.<
Why? I recently set it very high so that I could ensure I get more high-skill researchers, since they seem to take so much time to level up on their own, and 1 25% researcher is better than 5 5% researchers any day.
Actually, I believe it doesn't even affect the skill of commanders you recruit. Here's the rollover text:
Set level of racial training. Default = 1. Each level adds 100 to grade points of academy crewmen. Academies produce (1000/training level) per year. Max level is 5.
Crewmen are the naval personnel that man (or woman) your ships (think about the crew requirements on your ship designs). When you increase the training level, you increase their talent (and ship grade), so a ship may be launched with, say 7% or 12% grade, rather than 0%. The upside is that this provides you with an early boost to ship capabilities. The downside is that increasing the training level directly affects the number of crew you recruit each year, which in turn means that if you are producing a reasonable number of ships, you could very easily fall behind on crew, producing new ships with
negative grade, indicating that they are undermanned, and reducing their performance until they can take on additional crew.
IOW:
Crew Training Level =1
# of Academies = 5
Total naval personnel trained in 1 year = (1000/1)*5 = 5000 crew.
Crew Training Level = 3
# of Academies = 5
Total naval personnel trained in 1 year = (1000/3)*5 = 1666 crew, or 1667 if the game rounds up.
Crew Training Level = 5
# of Academies = 5
Total naval personnel trained in 1 year = (1000/5)*5 = 1000 crew
You can see how increasing it will severely affect your ability to crew new construction. It may be feasible early on to use a high training level, but once you start building a proper navy, it just isn't practical.
Incidentally, I wish there was a way to change the average lifespan of humans ingame, to replicate antiaging treatments (okay, really, to preserve the good ones for a few centuries).