Did the hinge fall overboard? If you lost the hinge you are screwed.
Otherwise, its easy to cut a piece of lexan and replace the glass.
see this thread.
I recently shattered a glass vent window on my 265....long story...I'll spare you...
Luckily, all hardware remained onboard.
I replaced glass with acrylic sheet .220"x24"x18" from home depot.
Project went crazy easy...
I used the other window to trace the pattern with a sharpie. Marked the holes.
Used a 5 1/2"' 100 tooth circular saw..."took the line"
Sanded the edges.
Drilled the holes. (be careful. a bit will grab when it pushes thru) Drill from both sides to make clean hole and avoid problems.
Used a countersink bit to knock off edges.
Lightly glued into hinge piece using 5200. Its...