Just about any flat surface on a boat will soon have stuff on it, or under it if a lift-top. My nav desk nearly always has some stuff on it unrelated to navigation whether in the slip or at sea. Sometimes we use it in addition to the galley cabinet tops as a staging area to set up meals, etc. So it receives a lot of ancillary use. But when I need it as a nav station, that is how it functions and I could not be more pleased with that functionality. The top is large enough to lay open a chart book and to sit comfortably examining a chart, plotting positions, etc.; and large enough to store beneath the lift-top nav tools, charts, and logbooks, etc. along with other materials, such as the latest version of Coast Pilot No. 7, harbor maps, & tide books. When we were searching for the boat we have now (Bavaria 38E), up from a Pearson 30, my wife had one principal criterion--an enclosed head. Mine were a permanent navigation station that I could sit and work at, and the ability to routinely make a through-the-water speed of at least 7.5 kt. We got much more than that of course; but any boat lacking those features would not have been a strong candidate.
As for space; the seat itself is also a top-loaded storage box where I keep sailboat hardware such as snatch blocks and winch handles. Under the desk where my legs go I have off to the side a small Ritchie compass that I can read from my sitting position; my 7x50 binoculars in holder, a small inverter, plus that's where I mount my 1 million candlepower spot.
