We had a set of plywood covers all sized and such for the camp in Pass Christian. Took one person about a hour and a half to put them up and bolt them down. (Had nuts set in the 2X4's around the windows)
Had two windows that opened to the porch with the plywood cut "Oversize" about four inches with 1" spacers by the bolt holes. We left those windows open to allow for pressure changes. During Katrina they acted as drains..... Let the water in and out without either "Floating" the house or "Bowing" the walls to let it out after the surge.
Sometimes I wished we had kept it after the "Rebuild". (Had to strip it to a bare shell and refinish it as the water got up about 3'ft on the second floor) Other times I am glad it is gone......