Too bad the Nashorns were so unsuccessful, they were very nice looking little ships, though I've always had a soft spot for CDS and monitors.
Then you will be pleased to see the third ship of Nashorn-class, equipped with the 38cm-twin-turret of Yorck-class battlecruiser. Just turn on page back.
Btw: a monitor doesn't have to look nice...
I compared the 28cm with the 38cm-gun and our mates here where right: the 28cm is a good gun for a cruiser but for shorebombing the disadvantages are too big.
28cm
max. range: 42600 m
max. 3,75 shots/min.
weight 315 kg with 21,8 kg explosives
barrel lifetime 300 shots
38cm
max. range: 55000 m
max. 2,1 shots/min.
weight 800kg with 64,2 kg explosives
barrel lifetime 242 shots
The delivered explosives and the range make the 38cm much more effective.