Yes, some of the mods are just the "ship" that takes the place of a submarine that you can operate. Some mods have Single Missions for you to check things out in. Very few include Campaign entries, due to the complexity of doing so. A playable ship cannot do any of the SpecOps missions, such as launching a raft for spy insertion. If you download a playable ship, and want to use a Single Mission already in the game, you would have to choose one that the submarine starts the scenario on the surface, else the mission will end rather quickly, due to the ship sinking...
- as mentioned above, read the documentation that comes with the mod, and see if you can figure-out what is or is not included in the mod.
btw: "Welcome to SubSim!"
