STUCK:Sea unit upgrades

[Maximilianus IV]

Hi I'm New

I want to upgrade a Man-O-War to whatever in CIV3 COMPLETE.

It doesn't seem to let me. I have money, over 5000, and I went to a city with a harbour. I have discovered the tech for battleship and destroyer.

I have everything I need to upgrade it.

Please help if you know why it wont upgrade.

 

[Turner]

The Man-O-War doesn't upgrade to anything. That's why you can't upgrade it.