I Have been experimenting with carspawner and vintage autos. It's not really that bad to get your own custom autos to spawn..just a matter of modifying the carspawner.dat file in your route's main folder. As long as the .s, the .sd and the ace texture files are all present and accounted for, it will work. I believe that a ship could be made to sail up the harbour by first sinking the road just below the surface of the water, adding the carspawner and making the adjustment to the .dat file. Only trouble is, you can only have one carspawner in your route so your streets and roads would contain a ship...gotta work on that................
here's a 1930's shot from over the ES Wharf...Yes - I even got my Keibler to work (That's the blue auto leading the pack) although it started out by going down the street backwards !
The problem with carspawns is you can only have one, so if you use your carspawn for running ships, they would run on your streets.
I have a motor boat and DC-3 in the Springfield Terminal route. They way I did it was to place track below the water level for the boat and below terrain level for the plane. You then make your boats and planes "engines" and run them as AI traffic. For the boat I set speed limits low, about 8 mph, for the plane, the route's maximum speed was set at somewhere around 85 mph which is low for a Dak, but the Dak was drawn at 1/2 scale and 85 mph looks like 170 mph in the sim and looked appropriate. The Dak is also drawn at 300 feet about the surface, so was the Piper Cub... I'm thinking an Argus might be in my future!
I will keep all that on the back burner and hope I dont have hydro failure before I actually get to use it. Anyway - I am not sure if ir what airline would have been flying from Yarmouth in the 1930's. I know there was a swordfish squadron there but maybe not in the '30s.