Found the button. You need to specially enable "Zone Pickup by Sea" in the SHQ unit admin, a submenu in one of the sidebars on the right.

That's pretty hidden. Now, at turn 50, my empire has it's first metal income outside of scavenging its starting hex! hooray!

I'm trying out the new addon and got a start on a metal-deprived peninsula. Managed to pacify a small islet with some ruins. Got a zone founded after waiting for a makeshift port card to generate and a had a recycler built, but the items generated by it aren't being moved back home.

Transfer of ...