Cruise liners have higher superstructures with more upper deck cabins which can have large windows and balconies. Recently there has been a decline in the number of portholes on larger ships. The porthole's thick glass and rugged construction, tightly spaced fasteners, indeed even its round shape, all contribute to its purpose of maintaining hull strength and withstanding the pressure of storm waves crashing against it. The design of the porthole is such that it achieves its humble purposes without sacrificing the integrity of the ship's hull. Bronze and brass are most commonly used, favoured for their resistance to saltwater corrosion. Metal components of a porthole are also typically very heavy they are usually sand-cast and made of bronze, brass, steel, iron, or aluminium. Much of the porthole's weight comes from its glass, which, on ships, can be as much as two inches thick. Portholes range in diameter from several inches to more than two feet, and weigh from several pounds to over one hundred pounds. Older portholes can be identified by the protruding collar of their base plate which may be up to several inches deep, thus accommodating the thickness of a wooden hull. Hinged porthole windows and storm covers are accessible from inside the ship's hull, and are typically fastened to their closed positions by hand tightening several pivoting, threaded devices, commonly referred to as "dogs". Storm covers are also used on navy and merchant marine ships to prevent interior light from escaping the ship's lower berths, and to provide protection from hostile fire. The storm cover is referred to as a deadlight in maritime parlance.
It is also used to block light from entering lower berths when darkness is preferred. The main purpose of the storm cover is, as its name implies, to protect the window from heavy seas. In addition, many portholes also have metal storm covers that can be securely fastened against the window when necessary. Sometimes the glass disk of a porthole is encased in a separate frame which is hinged onto the base frame so that it can be opened and closed. The porthole is primarily a circular glass disk, known as a 'portlight', encased in a metal frame that is bolted securely into the side of a ship's hull. Rows of portholes on the hull of Swedish HM Pansarskepp Gustaf V with gun Bofors 283 mm (until 1957).Ī porthole consists of at least two structural components and is, in its simplest form, similar to any other type of window in design and purpose. Eventually, it came to mean any opening in a ship's side whether for cannon or not. " Porte" was Anglicized to "port" and later corrupted to porthole. For heavy weather and when the cannons were not in use, the openings were fitted with covers, that were called porte in French, meaning " door". A French shipbuilder named James Baker was commissioned to solve the problem, which he did by piercing the ship's sides so the cannon could be mounted inside the fore and aft castles. The king insisted on mounting guns too large for his ships and therefore the conventional methods of securing the weapons on the forecastle and aftcastle could not be used. A deadlight is a hinged metal cover which can be clamped over the porthole to secure it in heavy weather.Īccording to the Navy Department Library, the word "porthole" has nothing to do with its location on the port side of a ship, but originated during the reign of Henry VII of England (1485). The use of the word "sidescuttle" instead of "porthole" is meant to be broad, including any covered or uncovered hole in the side of the vessel. It is also used in related rules and regulations for the construction of ships. When closed, the porthole provides a strong water-tight, weather-tight and sometimes light-tight barrier.Ī porthole on a ship may also be called a sidescuttle or side scuttle (side hole), as officially termed in the International Convention for the Safety of Life at Sea. It also affords below-deck occupants a limited view to the outside world. On a ship, 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. Though the term is of maritime origin, it is also used to describe round windows on armored vehicles, aircraft, automobiles (the Ford Thunderbird a notable example) and even spacecraft. Louis look out through the portholes of the ship while docked in the port of HavanaĪ porthole, sometimes called bull's-eye window or bull's-eye, is a generally circular window used on the hull of ships to admit light and air.
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