Comment 41 for bug 1584203

Bug 1824586 should be fixed now (unable to test while sitting in the train).

Wares are also routed via ports before you have ships, if I´m not mistaken. Then I don´t think routing should take that into account. Also, you might have ferries without ferry yards (e.g. if a script gives them or you destroyed the yard).
Waterways could be considered inexistent until a ferry is assigned to it. Then separate road networks connected only by waterway keep being separate economies until one waterway gets a ferry. But in my opinion, there is no point building a waterway if you don´t have a ferry yard yet, so its your own fault if wares get stuck…