What are subs good for? Are early aircraft going to be useless?

[DrPostman]

Playing the US and it's 1895. I've got 1 flotilla built
and 3 on the way. So far it looks like they are restricted
to the coast, so I guess they are good for harbor defense/
coastal defense? What else could they be used for? At
least they can puttle around the Caribbean in case some
Spanish warships show up (The Spanish American War
started early. I was given a "short term casus belli" so I
thought I'd better make use of it and declare war)..

I know it was early days for the subs but I now wish I hadn't
bothered building any. I hope aircraft are better. I've got
2 aircraft factories about a year away from being finished.

And now I've noticed the "American Hospital Ship" and the
Ocean Liner. The liner I see gives you prestige but what
the hell does the hospital ship do?

Has anyone compiled a list of the various force elements and
any special features that come with their construction and
use?

[Boernes]

Use the hospital ship when transporting troops, as the work like a field hospital. The prestige with Liners is new to me, other than that you can use them as additional transports

[Kensai7]

Has anyone built the aircraft carriers (Unit_CMN_AC01 and Unit_CMN_AC02)? Do they work as intended?

[DrPostman]

I didn't even know there were aircraft carriers. I realize the first launch from
a ship took place in 1910 but the first actual carrier, HMS Argus, didn't launch
until 1918 so with long build times I just figured the game would end before
you could put any to use. Argus didn't even join the fleet until 1920 due to
the need for extensive mods.

What countries get to build them?

[Sgt Bash]

I didn't even know there were aircraft carriers. I realize the first launch from
a ship took place in 1910 but the first actual carrier, HMS Argus, didn't launch
until 1918 so with long build times I just figured the game would end before
you could put any to use. Argus didn't even join the fleet until 1920 due to
the need for extensive mods.

What countries get to build them?

Whoever researches the tech.

[Kensai7]

These are "common" (CMN) units so probably they are eligible to all. I wonder how this works... probably you can move "airplane" units onto them and send them to lands far away!

[Sgt Bash]

I did the Naval techs and can confirm that any faction can research the aircraft carrier techs. However, I have no idea what the unit actually does. In my game I am only in 1883 and therefore I will have to wait to find out the answer.

[DrPostman]

I'm at May 1900. I have 2 aircraft factories but I don't see any aircraft units to build
yet. I just initiated airship research and it says I can start Naval Aviation but I can't
see it on the research page yet. I'll report if and when I see new units and what they
are. I've had 2 auto factories for a decade now and no vehicles to be built yet.