I think there are valid arguments both for and against upleveling on time.  I also think it is rare and unique more to a nation's advantage traits than position abilities.

What I mean is when you look at UK, their national trait advantage is Repair +2, for the US, it's Fighter +2, and KM it's Engr +2.  Other nations have Restore, reload, bomber, etc.

In considering the sailor's role (Gunner), the best national trait to have would be reload, whereby you can make your gunner an Accuracy gunner and enjoy the reload national advantage.  Repair would be okay also, but eventually with Repairmen and Restorers your SD will hit 900 anyway. 

Similarly, a regular support slot sailor (Rep/Rest/Engr/Seaman/Medic) could enjoy a little more Repair, Restore, or Engr ability and delay classing allows the national trait to continue a little more.  On the otherhand if your national trait is Fighter or Bomber and you're upleveling a Gunner, it might not bring much advantage overall anyway.

If he doesn't have enough points to class his gunners, chances are he doesn't have enough points to trade.

You will need 50,000 points to trade if you're level 30 or over, 150,000 if you are under 30.

You will need the same amount of credits also. (to trade)

I had that situation once as well on a storage account. I just kept whatever 3-4 sailors I could roll and played a FF to gain a few points.  Essentially I shelved the sailors that needed classing.  Once I had enough creds, I changed those random stat sailors into CV/SS BOs.

Actually what I wanted to also say was this kind of thing should never happen.  We've talked about this before but the points given to a player to start account is not enough.  Especially if they go the CV route, the class changes require a lot more points.  It's not harmful to stay in a lower class ship while trying to earn credits but to miss classing because not enough points are available on a starting account seems inexcusable.

I had that situation once as well on a storage account. I just kept whatever 3-4 sailors I could roll and played a FF to gain a few points.  Essentially I shelved the sailors that needed classing.  Once I had enough creds, I changed those random stat sailors into CV/SS BOs.

Actually what I wanted to also say was this kind of thing should never happen.  We've talked about this before but the points given to a player to start account is not enough.  Especially if they go the CV route, the class changes require a lot more points.  It's not harmful to stay in a lower class ship while trying to earn credits but to miss classing because not enough points are available on a starting account seems inexcusable.