For quick exits to deal with locks I don’t need to open the roof right back so the original idea was to make it in two parts with a hinge right across the middle under a neoprene strip. That wouldn’t work though unless the middle of the roof was supported on something, otherwise it’s just fold in half and fall into the cockpit. Consequently I started by making rigid windows to replace the PVC screens.
The window frames are made from recycled Iroko (I think). Our eldest daughter’s in-laws old windows were made from really chunky Iroko(?) so when they had them replaced I grabbed the lot. I’ve also used it for steps inside the cockpit and various other odd jobs onboard. The frames have stainless steel hinges in the middle, the rear half drops into aluminium channel and the front half can fold back against it. In good weather the whole unit can lift out.