I think you may have written a post about this, but I couldn’t find it. I always thought that the royal fleet’s administration was out-of-sync with the rest of the continent’s medieval political development in the sense that it is much more centralized and permanent than any land force. Is this correct?

Discussed here.

Navies were historically always more centralized and permanent than armies, because of the fiscal and administrative complexities of ship-building. 

That being said, “more” is not the same thing as “entirely.” Medieval kings would “borrow” merchant ships to bulk up their navies, they sometimes required port-cities to maintain auxiliary navies, they hired mercenaries, etc. Likewise, while royal navies had more longevity administratively, the realities of irregular warfare and the lifetime of wodden ships meant that their size fluctuated drastically – so technically it would be a series of fleets rather than a permanent fleet.