How do you dock a ship in Harpoon Gold?

You join it to the destination group/port. That being said, there is no victory condition trigger or anything for doing that. Traditionally when orders talk about docking it is really on On Station victory condition so you need to be within a defined rectangle of area around the group/port.

OK, thanks very much. How big do the rectangles tend to be?

Since 2008.065 you can look for yourself. I've attached a screenshot of each (O) vs (Alt F5)

==============

- Chg:0000 GE Added hotkey O to show any On Station rectangles for the

player's side. Press O to show them, O again to hide them.

In debug builds, Alt-F5 will show on station rectangles

once for all sides (the ones for Blue will be blue color,

Red will be red, etc.)