Jewish refugees aboard the SS St. Louis look out through the portholes of the ship while docked in the port of Havana
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. It also affords below-deck occupants a limited view to the outside world.[2] When closed, the porthole provides a strong water-tight, weather-tight and sometimes light-tight barrier.
A 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. This term is used in the U.S. Code of Federal Regulations.[3] It is also used in related rules and regulations for the construction of ships.[4] 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. A deadlight is a hinged metal cover which can be clamped over the porthole to secure it in heavy weather.
According 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 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 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. 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". "Porte" was Anglicized to "port" and later corrupted to porthole. Eventually, it came to mean any opening in a ship's side whether for cannon or not.[5]
StructureEdit
A brass porthole with hinged window and storm coverRows of portholes can be seen on the hull of HMS Cornwall, a British heavy cruiser from the 1920sRows of portholes on the hull of Swedish HM Pansarskepp Gustaf V with gun Bofors 283 mm (until 1957).
A 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. 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. 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. In addition, many portholes also have metal storm covers that can be securely fastened against the window when necessary. The main purpose of the storm cover is, as its name implies, to protect the window from heavy seas. It is also used to block light from entering lower berths when darkness is preferred. The storm cover is referred to as a deadlight in maritime parlance.[6] 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. 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". 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.
Portholes range in diameter from several inches to more than two feet, and weigh from several pounds to over one hundred pounds. Much of the porthole's weight comes from its glass, which, on ships, can be as much as two inches thick. Metal components of a porthole are also typically very heavy; they are usually sand-cast and made of bronze, brass, steel, iron, or aluminium. Bronze and brass are most commonly used, favoured for their resistance to saltwatercorrosion. The design of the porthole is such that it achieves its humble purposes without sacrificing the integrity of the ship's hull. 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.
Recently there has been a decline in the number of portholes on larger ships. Cruise liners have higher superstructures with more upper deck cabins which can have large windows and balconies. Most warships no longer have portholes on their main hulls as they could weaken them and modern vessels have air conditioning and strong lighting below decks meaning that they are no longer necessary.[7]
Portholes on spacecraft must be made from glass that can survive rapid temperature changes, without suffering the cracking that can result from thermal shock. Those on the International Space Station were made from quartz glass mounted on titanium frames, covered with enamel. These were designed to be opened[citation needed] though no returning astronaut has done so. The windows also have shrouds or doors to protect them from micro-meteorites.[8]
On the Apollospace capsules a porthole was located in the hatch that the astronauts used at the beginning and end of each flight.
Portholes on submarines are generally made of acrylic plastic. In the case of deep diving submarines, the portholes can be several inches thick. The edge of the acrylic is usually conically tapered such that the external pressure forces the acrylic window against the seat. Usually such windows are flat rather than spherically dished. This decreases the area that can be viewed, but eliminates distortion associated with curved glass.
^"Rules for Classification and Construction, Ship Technology, Seagoing Ships" (PDF). Section 21 Hull Outfit, Side Scuttles, Windows and Skylights: DNV GL. July 2016. Retrieved 2020-12-13.{{cite web}}: CS1 maint: location (link)
^Where have all the portholes gone 2014-09-29 at the Wayback Machine. Retrieved 24 April 2015
porthole, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jstor, april, 2016, lear. This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Porthole news newspapers books scholar JSTOR April 2016 Learn how and when to remove this template message A porthole sometimes called bull s eye window or bull s eye 1 is a generally circular window used on the hull of ships to admit light and air 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 Jewish refugees aboard the SS St Louis look out through the portholes of the ship while docked in the port of HavanaOn 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 It also affords below deck occupants a limited view to the outside world 2 When closed the porthole provides a strong water tight weather tight and sometimes light tight barrier A 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 This term is used in the U S Code of Federal Regulations 3 It is also used in related rules and regulations for the construction of ships 4 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 A deadlight is a hinged metal cover which can be clamped over the porthole to secure it in heavy weather Contents 1 Etymology 2 Structure 3 Spacecraft portholes 4 Submarine portholes 5 See also 6 ReferencesEtymology EditAccording 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 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 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 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 Porte was Anglicized to port and later corrupted to porthole Eventually it came to mean any opening in a ship s side whether for cannon or not 5 Structure Edit nbsp A brass porthole with hinged window and storm cover nbsp Rows of portholes can be seen on the hull of HMS Cornwall a British heavy cruiser from the 1920s nbsp Rows of portholes on the hull of Swedish HM Pansarskepp Gustaf V with gun Bofors 283 mm until 1957 A 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 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 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 In addition many portholes also have metal storm covers that can be securely fastened against the window when necessary The main purpose of the storm cover is as its name implies to protect the window from heavy seas It is also used to block light from entering lower berths when darkness is preferred The storm cover is referred to as a deadlight in maritime parlance 6 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 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 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 Portholes range in diameter from several inches to more than two feet and weigh from several pounds to over one hundred pounds Much of the porthole s weight comes from its glass which on ships can be as much as two inches thick Metal components of a porthole are also typically very heavy they are usually sand cast and made of bronze brass steel iron or aluminium Bronze and brass are most commonly used favoured for their resistance to saltwater corrosion The design of the porthole is such that it achieves its humble purposes without sacrificing the integrity of the ship s hull 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 Recently there has been a decline in the number of portholes on larger ships Cruise liners have higher superstructures with more upper deck cabins which can have large windows and balconies Most warships no longer have portholes on their main hulls as they could weaken them and modern vessels have air conditioning and strong lighting below decks meaning that they are no longer necessary 7 Spacecraft portholes Edit nbsp Cosmonaut Sergei Krikalev in front of a porthole in the Zvezda component of the International Space StationPortholes on spacecraft must be made from glass that can survive rapid temperature changes without suffering the cracking that can result from thermal shock Those on the International Space Station were made from quartz glass mounted on titanium frames covered with enamel These were designed to be opened citation needed though no returning astronaut has done so The windows also have shrouds or doors to protect them from micro meteorites 8 On the Apollo space capsules a porthole was located in the hatch that the astronauts used at the beginning and end of each flight Submarine portholes EditThis section does not cite any sources Please help improve this section by adding citations to reliable sources Unsourced material may be challenged and removed April 2016 Learn how and when to remove this template message Portholes on submarines are generally made of acrylic plastic In the case of deep diving submarines the portholes can be several inches thick The edge of the acrylic is usually conically tapered such that the external pressure forces the acrylic window against the seat Usually such windows are flat rather than spherically dished This decreases the area that can be viewed but eliminates distortion associated with curved glass See also Edit1900 Hoboken Docks fire Clear view screen Deck prism nbsp Wikimedia Commons has media related to Portholes References Edit nbsp Look up porthole in Wiktionary the free dictionary bull s eye in the American Heritage dictionary 10 things I wish I knew before going on my first cruise The Daily Telegraph 9 June 2017 Title 46 U S Code of Federal Regulations Sec 45 139 Side scuttles ISO 1993 ISO 1751 Shipbuilding and marine structures Ships side scuttles International Organization for Standardization With permission from http www history navy mil library online origin htm por Archived 2011 02 12 at the Wayback Machine Rules for Classification and Construction Ship Technology Seagoing Ships PDF Section 21 Hull Outfit Side Scuttles Windows and Skylights DNV GL July 2016 Retrieved 2020 12 13 a href Template Cite web html title Template Cite web cite web a CS1 maint location link Where have all the portholes gone Archived 2014 09 29 at the Wayback Machine Retrieved 24 April 2015 manchikoni com Retrieved from https en wikipedia org w index php title Porthole amp oldid 1138107216, wikipedia, wiki, book, books, library,
