Yes all the info I have shows a single rudder, but Lou and some of the guys have found a couple of sources that show it having twin rudder posts, a picture of the top of the steering room without the deck on I was told. Since the two classes had different steering gear, Furutaka class a standard steam engine driving hydraulic rams moving the rudder, and the Aoba class electo-hy-draulically driven gears. I remember seeing a drawing somewhere of the top view of the stern of the Aoba, and it does look ike it has additional rudder posts, but they had the large gears mounted on them, on either side of the center shaft which was the rudder post itself. Of course now that I'm looking for that drawing again, I have not been able to find it. I once found a site with multiple 3D cad drawings of a Nagato that was fantastic, of course my computer locked up, it was 3 am in the morning and I went to bed, next day I looked for hours and never found that again either.
I have found a set that someone else did that are not bad, but the one time I found a different 3D of the Nagato last year, and have never found it again, I have looked many times. Curt do you have the link for the one you have seen, maybe it is the one I can't find again.