Seaplane

From WOI Encyclopedia Italia

A DeHavilland Single Otter floatplane in Harbour Air livery.
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A DeHavilland Single Otter floatplane in Harbour Air livery.

A seaplane is an aircraft designed to take off and land (correctly, though less commonly termed, "alight") upon water.

These aircraft are occasionally called hydroplanes, based on usage in several Romance languages, which is rare in English.

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Types of seaplane

There are two types of seaplane: the floatplane and the flying boat.

  • A floatplane has slender pontoons mounted under the fuselage. Two floats are common, but many float planes of World War II had a single float under the main fuselage and two small floats on the wings. Only the "floats" of a floatplane normally come into contact with water. The fuselage remains above water. Some small land aircraft can be modified to become float planes and vice-versa.
  • In a flying boat, the main source of buoyancy is the fuselage, which acts much like a ship's hull in the water. Most flying boats have small floats mounted on their wings to keep them stable.
 A Twin Engine Grumman Goose flying boat.
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A Twin Engine Grumman Goose flying boat.

It should be noted that some people feel that the term "seaplane" should only be used to refer to aircraft with floats in place of landing gear, with a flying boat being a distinct type in its own right. For convenience, the above definitions and assumption that flying boats are a type of seaplane are used herein.

An amphibious aircraft can take off and land both on conventional runways and on water, whereas a true seaplane can only take off and land on water. There are amphibious flying boats and amphibious float planes, as well as some hybrid designs, e.g., a seaplane with retractable floats. However, most modern seaplanes are amphibious and of traditional design.

Seaplane uses and operation

Numerous modern civilian aircraft have a floatplane variant, usually for light duty transportation to lakes and other remote areas. Most of these are offered as third-party modifications under a supplemental type certificate (STC), although there are several aircraft manufacturers that build floatplanes from scratch, and a few that continue to build flying boats. Many older flying boats remain in service for fire-fighting duty, and Chalk's Ocean Airways still operates a fleet of flying boats in passenger service. Purely water-based seaplanes have largely been supplanted by amphibious aircraft.

A DeHavilland Twin Otter floatplane in West Coast Air livery.
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A DeHavilland Twin Otter floatplane in West Coast Air livery.

Seaplanes can only take off and land on water with little or no wave action and, like other aircraft, have trouble in extreme weather. The size of waves a given design can withstand depends on, among other factors, the aircraft's size, hull or float design, and its weight. Flying boats can typically handle rougher water and are generally more stable than floatplanes while on the water.

Rescue organizations, such as coast guards, are among the largest modern operators of seaplanes due to their efficiency and their ability to both spot and rescue survivors. Land-based airplanes cannot rescue survivors, and many helicopters are limited in their capacity to carry survivors and in their fuel efficiency compared to fixed-wing aircraft.

Seaplanes are also often used in remote areas such as Alaska (which has the highest per capita number of floatplanes in the United States) and the Canadian outback, especially in areas with a large number of lakes convenient for takeoff and landing. They may operate on a charter basis or provide scheduled service. Many residents of these remote areas operate their own personal floatplanes, too.

Within the European Union, Greece is the only country that uses seaplanes to connect its many islands to the mainland. In the Western Hemisphere, there are numerous seaplane operators in the Caribbean Sea that offer service within or between island groups.

History of seaplanes

Early development was carried out at Hammondsport, New York by Glenn Curtiss who had beaten Alexander Graham Bell and others in the Aerial Experiment Association.

Seaplane airbase at Natal (Rio Grande do Norte), Brazil.
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Seaplane airbase at Natal (Rio Grande do Norte), Brazil.

During World Wars I and II, many navies used seaplanes for reconnaissance and anti-submarine warfare. Most battleships carried one or two catapult-launched seaplanes to spot targets over the horizon for the big guns, or to fight off enemy reconnaissance planes. The failure of the German battleship Bismarck's Arado 196 seaplane to hunt down a PBY Catalina reconnaissance aircraft is said to have contributed to the ship's demise.

The H-4 Hercules makes a demonstration flight in 1947.
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The H-4 Hercules makes a demonstration flight in 1947.

One of Howard Hughes' best-known endeavors was the H-4 Hercules (nicknamed the "Flying Lumberyard" and, more famously, "Spruce Goose" — although its frame was built predominantly of birch), a massive flying boat completed just after the end of World War II. The Hercules only flew once (with Hughes at the controls) in 1947. The plane was originally commissioned by the U.S. government for use in World War II, but was not completed until after the War.

Today, seaplanes are mostly considered obsolete for military purposes; seaplane tenders, such as HMS Engadine, fell out of use after the 1950s with the general demise of the seaplane, the advent of the first stable, fully-controllable helicopter, and continued development of the modern aircraft carrier.

See also