Harbour not working?

[pauleden]

Hopefully the picture is self explanatory. I desperately need that iron, or the Spanish are going to own me, but for some reason, the harbour in Homer is not trading it over to the harbour in Oxford, on my home island.
Note that the horses in both cities are independant. Both islands have a horse source.

What's going on then? Any ideas?

Thanks in advance,

Paul
(PTW 1.27, playing the English on a normal world)

 

[Tatran]

You need Astronomy to establish the trade route.
There are seasquares between the two cities.

 

[Tomoyo]

If you can, building the Great Lighthouse will let you trade between the two cities. Also, if you really are desperate, you can build warriors and send them to Homer to upgrade, and ship them back.

 

[Ginger_Ale]

Yep, Astronomy for trade over seas, and Navigation or Magnetism for trade over oceans.

 

[pauleden]

Well, I didn't know that. Thank you very much!