Cabin casement window

I agree, the 39-020 and 39-021 look like they could work, along with the 39-520 track. As for the lock, how about something like our 90-152? This seems to be the best solution for twin windows like what you show. I think if you were to install two locks on one sash and their keepers on the other, that might do the trick. However, you will need a type of wood trim on one sash to close up the gap between them so no one could slide a thin screw driver and unlock the window. We also carry the 40-012 slide bolt. If you go this route, you'd want one at the top and bottom of each sash.