These prints can be used with a galvanized 5/16 bolt, nut, and washer to mount a Lowrance transducer in the scupper holes of a Moken 12.5 Kayak. I imagine it could also be easily customized to other kayak makes and models if not used as is.
Check out the mounting here: http://lilmikey.com/2016/05/06/fishfinder-mount-in-moken-12-5/
You should definitely print them in the orientation in the STL file. I've tried alternatives and it gets sloppy. I used PETG and some decent infill to sturdy them up.