If you are replacing an old window with a new one it is always best to remove the old window and take a pattern of the hole in the wheelhouse wall. If you do not want to remove the old window until the new one arrives then it would be best to remove the inside trim to get access to the actual cutout in the wheelhouse wall. Cut a rigid cardboard to the approximate shape of the window about 1 inch larger on all sides than the window opening. Cut V-notches, two per side close to the corners but away from the radius corners, as in the illustration.

From inside the wheelhouse, with the inside trim removed, place the cardboard over the hole and adjust it so that you can clearly see the cutout line in all 8 notches. Draw a line with a sharp pencil (not a dull marker) to mark the hole cutout position, not the old window. Label the pattern with TOP, INSIDE, and a location number before you bring it down so that you do not get it confused with other window patterns. Marinelite Windows all have 3 1/4″ radius corners at the cutout (drawn from a 6 1/2″ diameter disk). If your corners are of a different radius, please advise us so we can size the window for the best possible fit.

When your wheelhouse is up and you are ready to cut out the window openings you must determine the size and location of your windows. In most cases it is best to follow the contour of your wheelhouse edges. With a straight edge, and a sharp pencil, mark the cutout as if you would be cutting out a window with sharp corners. With all 4 sides marked out, take a 6 1/2″ disk and precisely place it in a corner so that it touches both lines. Draw a pencil line around the outside of the disk. Continue this procedure on the 3 other corners. Mark the panel with TOP, INSIDE, and a location number before you cut out the panel so that you do not get it confused with other window cutouts.

Draw 4 straight lines illustrating the cutout shape and size. Make sure all 4 lines intersect in all the corners. Mark exact lengths of each side of the cutout (corner to corner and parallel to the line). Then mark the exact dimensions from the upper left corner to the lower right corner and the other dimension from the upper right corner to the lower left corner. This is the most accurate and simplest way to draw a window cutout. The radius will always be 3 1/4″ so there is no need to mark it on the drawing.

Be precise. Measure accurately, then check for errors using the Dimension Checker Tool below.