A seaplane is an aircraft designed to take off and alight upon water.

Types of Seaplanes

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

• A float plane 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 float plane normally come into contact with water. The fuselage remains above water. Some small land aircraft can be modified to become float planes.
• In a flying boat, the main source of buoyancy is the fuselage, which acts as a ship's hull in the water. Most seaplanes have small floats on their wings to keep them stable.

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

Seaplanes can only take off and alight 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 land depends on how big the aircraft is, and the specifics of its shape. Flying boat seaplanes can handle rougher water, and are generally more stable than the float planes on the water.

It was common to launch small reconaissance seaplanes from shipboard catapults.

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.

One of the largest users of seaplanes are rescue organizations such as coast guards because the same aircraft can be used for spotting and rescuing survivors. Seaplanes are much more fuel-efficient than helicopters and unlike helicopters, can land when they run out of fuel, weather permitting.

Seaplanes are often used in remote areas such as Alaska and the Canadian outback, especially in areas with a large number of lakes convenient for takeoff and alighting.

During World War 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 Bismarck's Arado 196 seaplane to hunt down a PBY Catalina reconaissance aircraft is said to have led to Bismarck's destruction. However, seaplanes are mostly considered obsolete for military purposes. Seaplanes would seem an obvious choice for military aircraft at sea, but there are good reasons why aircraft carriers and planes that cannot alight on water are the choice of the military. Seaplanes tend to have mediocre aerodynamics because of the air drag and mass of the floats. They can alight on water, but their carrier ship must stop to pick them up. In a battle, stopping is never a good idea. Moreover, large ships need a long time and much space to slow down and make a rendez-vous with a small plane.

Numerous modern civilian aircraft that have a floatplane variant usually for light duty transportation to lakes and other remote areas. Flying boats have remained in service for fire-fighting dutes. Often a amphibious aircraft that can land on land as well alight on water has supplanted a pure waterplane.

See also:

• Flying boat
• List of flying boats and seaplanes
• Amphibious aircraft