Here’s a small Perko rectangular porthole that is cast brass and weighs just over 22 pounds.  The outside of the frame measures 19 x 10 inches and has 14 mounting holes. The glass measures 16 x 7 inches. On the back, the raised flange measures about 17 1/4 x 8 1/4 inches x 1 1/2 inches deep. The frame on the back for mounting the porthole to the inside of the hull is removable. The two dogs work and the window opens freely; this porthole includes the original screen with no holes, just some waving, and the original glass has minor surface scratches.