Amphibious helicopter

An amphibious helicopter is a helicopter that is intended to land in and take off from both land and water. Amphibious helicopters are used for a variety of specialized purposes including air-sea rescue, marine salvage and oceanography, in addition to other tasks that can be accomplished with any non-amphibious helicopter. An amphibious helicopter can be designed with a waterproof or water-resistant hull like a flying boat or it can be fitted with utility floats in the same manner as a floatplane.

Helicopters have taken a primary role in air-sea rescue since their introduction in the 1940s. Helicopters can fly in rougher weather than fixed-wing aircraft, and they can deliver injured passengers directly to hospitals or other emergency facilities. A practical amphibious helicopter first appeared in 1941 and the water-landing feature soon proved its worth. Non-amphibious helicopters were required to hover above the scene of a water accident and utilize a hoist but amphibious helicopters were capable of setting down on the water to effect a rescue more directly.

In 1941, Igor Sikorsky fitted utility floats (also called pontoons) to the Vought-Sikorsky VS-300, making the first practical amphibious helicopter. In the 1940s and 1950s, some models of helicopter such as the Bell 47 and 48 and the Sikorsky R-4 and R-6 were fitted with utility floats so that they could rest on both water and land.

Pontoons can be filled with air or they can be utilized for storage of fuel or supplies. In 1949, Sikorsky produced the H-5H with both wheels and pontoons.

The Sikorsky S-62 Seaguard was the first amphibious helicopter made with a flying boat hull—the prototype flew in 1958. Utilizing many components of the earlier S-55, the S-62 proved the idea, and Sikorsky flew their S-61 Sea King prototype in 1959 for the U.S. Navy, a model intended for anti-submarine warfare. Both the S-62 and S-61 were ready for delivery in 1961. Sikorsky produced 1100 S-61s, including some that were not watertight: a longer cargo-carrying version was given rear doors and a ramp. Sikorsky licensed other manufacturers such as Agusta, Mitsubishi and Westland to produce variants of the S-61.

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