What could possible the Church (or Dohlar, for example) produce to compensate the Charis naval superiority - at least, partially? They certainly will not be able for a long time to challenge Charis on the high seas, but in the coastal waters - it's a different story.
I think first of all about the possibility of some mines. the Church is familiar with the Charisian landmines; obviously does not require any special effort to think of the concept to the sea mine. Without electricity, the naval mines wouldn't be so effective as on earth, but evem with primitive firing mechanism they could be dangerous for enemy ships. And they are simple and relatively cheap to produce, and they COULD make Charisian coastal operation a lot more difficult.
The next possible thing is some sort of "disappearing" mounts for coastal artllery, which allows the guns to be raised for a shot and lowered to recharge. Similar gun mounts, nestled in the pits, will be much more difficult target for naval guns than old-style batteries.
And, of course, we must not forget that the Church has (now) at least a fundamental understanding of the steam engines - i.e. of steam engines and steam industrial equipment. Of course, it will take time for the development of these technologies, and they will (at first) is much more primitive than that of Charis. But it looks possible that the Church will be able to create at least some armored battleships for coastal defense; Low Sides, slow-moving, but more or less adequately protected, so that the battleships of Charis could not just destroy them from the overwhelming range and would be forced to came in range of inferior Church guns.
