I thought we called those strudders not z-drives. The graupner z-drive is scale in appearance and imo a z-drive. Calling those robbe drives z-drives just marketing, they''re steerable outdrives/strudders.

Could put a z-drive in a 20" boat, just have to figure out what kind of boat. In the processyou could decide you want an outboard but lots of real boat can either use a z-drive or an ob.