Coming soon in Patch 6.2 we will be able to build Shipyards in our Garrisons. The ships will be required to get to the new zone, Tanaan Jungle. WoWHead has a great guide based on what is currently on the test server.
There are five types of ships (Carrier, Galleon, Destroyer, Transporter, Submarine). The type determines one of the ship’s abilities/counters. With a Level 1 Shipyard, you can only build Destroyers or Transporters though. Ships are built with Garrison resources.
Within each ship type, there are specific ships named after lore figures. When a ship has finished building, you will randomly get one of the ships in that category. The “Crew” determines another ship ability, which can range from increased gold to bonus success. These offer bonuses instead of counters, and are similar to Follower Traits.
An key difference from Followers is that ships can be destroyed (and easily replaced). If you fail a Dangerous mission, there is a 50% chance your ship will be destroyed. As building ships are not that expensive and leveling them is not a ton of experience, you’re expected to replenish your fleet fairly easily.
Ships currently do not have levels or item levels. They all start off at Uncommon and can be upgraded to Rare and Epic from experience earned on Naval Missions.