Features
A porthole is a generally circular window used on the hull of ships to admit light and air. The function of a porthole, when open, is to permit
light and fresh air to enter the dark and often damp below deck quarters of the vessel. It affords below deck occupants a limited, but often much
needed view to the outside world. When closed, the porthole provides a strong watertight,weather-tight and sometimes light-tight barrier.
