Not to build a naval base. To activate it in the supply network. A bit different. That is probably why the AI 'never' builds a naval base on its own. And why their navies is such at a dismay when sent off range.
I remember playing a recent game where it was 1905 and I tag switch to England. They were only just then researching the tech to build naval bases. I thought it absurd that the worlds naval superpower was incapable of naval bases.