For a long time, the Reiklands had a large, yet weak navy. Most of the ships are galleys of relatively small sizes, and confined to the three seas of Trimaris proper. This state of affairs was maintained by aggressive action of the Kraken Elves who ruthlessly enforced treaties limiting the kinds of ships that could be built in Trimaris. They were also forbidden to mount more than a couple small cannon and deck guns.
Recently, large sea-going vessels were built secretly in a forgotten dwarven port in the Forgotten Sea. 12 ships of massive size, equipped with 20 or more large cannon and so high that the Kraken have difficulty in boarding them have changed the balance of power dramatically. Kraken ships have been swept out of Trimaris, and are currently forced to operate outside the Inner Seas. It is rumored that even larger ships are being designed, although the Reiklanders have lost the security of the lost Dwarven port.
Estalia has the largest, most powerful human navy in existance, and was the only force capable of standing toe-to-toe with the Kraken Elves. They have had strong sea-going vessels for many years, but it is suspected that the new Reikland designs are actually Estalian in origin. The Estalian versions of these ships have yet to be seen though.
Tilean ships are similar to the Reikland galleys. There is no single navy, but a hodge-podge of naval forces belonging to the various City States. It is not uncommon for Tilean vessels to engage in opportunistic piracy.
Bretonnia has a few more ocean-going ships than the Reiklands, but by-and-large they have little interest in long sailing trips. The knightly culture has never acclimated itself to the idea of seeing any glory in a battle that doesn’t take place on horseback. Merchant ventures are even less glorious, so they leave those voyages and risks to the Marienburgers.
Marienburg has a strong navy of sea-going vessels, but nothing to match the newest Reiklander ships. They dominant the northern trade routes to Cathy and Nippon and other lands. Their powerful fleet spends much of its activity in holding off Chaos raiding fleets, Norcan raiding fleets and scrapping with the Kraken Elves.
The Dwarven Fleet
No one has seen any dwarven ships, yet the massive stone doors of the Rockmouth Port have been seen to open occasionally when no ships leave. It is suspected that the dwarves may have taken their proclivities for staying underground to extend beneath the water as well. If they really do have submarines, they are clearly the only engineers capable of such a feat.
The Kraken Elves
This is the largest single navy in the world. Graceful, high galleys full of elven marines have spent hundreds and hundreds of years enforcing high tax tarriffs on all sea trade, making the Kraken Elves very wealthy in the process.
They fought to a stand-off with Estalia while still maintaining their tax fleets. With their recent expulsion from the Inner Seas of Trimaris though, they have a lot of ships with very little to do. It is likely that the conflicts with Estalia will ramp up greatly in the near future, and they are already hotter than they have been in decades.
One note about construction: the elven ships are manufactured with no nails or other metal joints. All joints are examples of high woodcraft, and the only metal used on the ships is in the armor and weapons of the troops, and the points of the spear thrower shot. Whether this is due to Elven fastidiousness about their craftsmanship, or the legends of a floating magnetic mountain that appears at random in the great sea is a matter of debate.
The High Elven navy is relatively small, given the greatness of the civilization. This is because the Kraken Elves really are the naval arm of the High Elves. This matter is kept very secret though, and while the elven ship all share similar craftsmanship, they make sure they have very different style and appearance.
The Dark Elves
The Dark Elves have no surface navy. Instead, they operate fleets of flying Dragon Ships that allow them long range raiding capabilities. People everywhere, but especially in the Forgotten Sea, flee in terror when the black forms of dragons are seen flying on the horizon.