front window should be held in with a clamp ring on the inside. Use the black butyl tape to seal the window frame to the fiberglass. Or are you talking about sealing the plexiglass to the window frame. Your best option may be to buy a rear window from Scamp
, about $150 plus shipping, and install that in the front, then you will have a window that you can open. Another member here has done it. I replaced our rear window with a Scamp
window, had to widen the opening by about 1" total, 1/2" each side. If you do go with a Scamp
window, front or rear, DO NOT use the foam tape that Scamp sends with the window, it will leak, use the butyl tape. Also I had to put the clamp ring on backwards because of the wall thickness. Our Uhaul does not have the gravel guard either. I had a lot of leakage problems, front window included, finally got it all resolved!! Robert has the info as to where to get custom sized windows at a reasonable price, better than anywhere I could find.