I propose giving workers the ability to build a Port similar to their current ability to build an Airfield. Ports could be built on any square that borders a body of water (if a city on the square could have a Harbor, then a Port can be built in the square). A Port would function like a Harbor for establishing trade routes and establishing access to resources. It might also function as an improvement that increases food production in the square by one (from fishing).

Hank Griffin

I have thought of similar ideas in the past. I have always thought that this should be implemented. For example, there is a resource on an island, but it is impractical to build a city there. You could "claim" the resource, build a port on the water, and build a road to the port. Another civilization could not gain control of the tile the resource is on or the tile the harbor is on or anywhere for one square around it.

I completely agree with this idea.

A "build port" worker action to connect sea trade without having to build cities would be an outstanding addition.

This idea makes sense since there are Airfields that aren't attached to cities, but I think it would be better off not being used, except in specific situations. Ports have historically been centers of trade, and where there is a center of trade you will see a lot of people living/working there. So while Airfields can be thought of as something akin to Air Force Bases (which are generally removed from metropolitan areas (but not always)) ports serve a different purpose.

Now, a good place for this kind of thing would be where you have one-tile mountain islands with a resource on it that you can't get too because cities aren't allowed on mountains. By putting a colony/port on top of it, you get access to that resource.

I really like it the idea to make a fishing area.
When your capitol needs that extra food to make settlers faster, you can decide to sacrifice a worker to make a fishing colony.
When you made your railroads, and dont need your workers, you can line your coast with fishing areas.

strategy++

Too overpowered IMO.

I saw a suggestion of build port/airport in colony.It avoids useless one-tile-mountain island with iron/coal/U .

I support this idea but I think it should work like the 'colony' does in Civ3 in the sense that when a rival civilizations borders expand and the port is within those borders the port should disappear (meaning its of no use to your civilization). This would also mean that other cities with harbours, or connected to cities with harbours would be the only ones that could take advantage of a resource that the port connects them too (provided a road is built to the resource and then to the port of course). I'm not to keen on having fishing harbours though because I think it would be too powerful of an improvement that could lead to a proliferation of food production within a city.