Well it would not be that simple to add, but I think the best way would to be have an improvement in a way.
Each canal improvement would give extra commerce I would think, and act like a fort in the sense that ships could travel through it. And then have various stages of upgrading the improvement.
Now I would like something that would effect different types of ships allowed to pass based on what stage of the canal improvement is.
And for the wonder would be neat to give so many free canal improvements.
But again not something real simple either.
Canals -- are they a worker tile improvement, wonder, and/or city building?
so if it was a worker improvement graphically it would look like a path/road/rail kind of graphic.
question: would a canal have to be linked between cities and or a city and the ocean in order to add its benefit, or just wherever it is put regardless of linkage (like a road doesnt have to be linked in order to kick in its tile benefits)? Methinks like a road...
As a wonder the possibilities are much easier and maybe less poignant for that which canals historically meant... we could easily do the Panama Canal Wonder, and I apologize since my playing time w/. ROM is limited thus far if there is such a wonder already...
If it is a city improvement, my only concern is that canals are connectors that thread between two or more locations so a single city having its own individual canal building just seems to me to fall short of the historical reality of canals... again like a wonder probably easy to do, a canal treated much like a river port building or a ROM glassblower?
to me it has to be a worker improvement... graphically like a road...
your ships concept is fascinating. barges, flatboats, ferries, and when i google the phrase "canal boat" i got "Narrowboat". see
http://en.wikipedia.org/wiki/Narrowboat. can there be made a unit that only travels on a specific tile? if there are modern canals then any size ship can be accommodated (hull depth - i think for ease assume battleships and aircraft carriers can go through CIV modern canals). expiring for the advent if the railroad advancement would make sense for the ancient canals but not the modern canals like Suez. So there needs to be an age difference and tech kick in for the ancient (think roman canals in UK) to modern (Suez). wow...
by the way, you just made me think if one can do canals, then why not the same thing with superhighways? in theory (and spank me again if ROM 2.62 has this and i just haven't played enough yet to know it) the same worker enhanced tile improvement that works for canals could work for path/road/paved road/highway/superhighway... like ancient canal/modern canal? (btw to me a RR should stop a unit upon entering and exiting to simulate the loading of the RR cars whereas highways could allow on and off same turn traffic in the same way that unloading a boat transport stops the unit for the turn [loading/unloading should be worked into RRs]) .
Ok now i can't shut myself up, and g*d forbid ROM gets over complicated already but distance traveled is time relevant to the progress of that transportation system. ancient canal boats could only go so many "tiles" a turn... and RRs do act like canals (as prior paragraph said, a road becoming a modern superhighway) so a RR should scale up in distance traveled based upon development of the engine itself. just play railroad tycoon. in CIV a RR at day 1 is the same as a RR in the year 2500 but in reality there is steam, coal, diesel, electric, and mag. a steam engine should be limited to lets say 4 or 8 spaces in a turn, whereas a modern diesel/electric could go many miles... such as 24 or 48 in a single turn? future tech mag tubes would be like the old versions of Civ where any connection into the RR means you can move across the continent in a single movement? i haven't thought this out, but distance scale should be relevant to the technological advancement! there is a modern train that leaves California with fresh produce and arrives in New York: "the shipment originating in Delano, Calif., will arrive in Schenectady, N.Y., 128 hours later", see
http://www.ble.org/pr/news/headline.asp?id=23905.
thanks for spouting with me!
oy vey...



its beer time...
