Airboat

Airboating has become a popular ecotourism attraction in the Florida Everglades in the U.S.

An airboat

An airboat is a flat-bottomed vessel (jon boat) propelled by an aircraft-type propeller and powered by either an aircraft or automotive engine.^[1] They are commonly used for fishing, bowfishing, hunting, and ecotourism.

Airboats are a very popular means of transportation in marshy and/or shallow areas where a standard inboard or outboard engine with a submerged propeller would be impractical, for example, in the Florida Everglades, parts of the Indian River Lagoon, the Kissimmee and St. Johns Rivers, as well as Louisiana Bayous.

Overview

The characteristic flat-bottomed design of the airboat, in conjunction with the fact that there are no operating parts below the waterline, permit easy navigation through shallow swamps and marshes; in canals, rivers, and lakes; as well as on frozen lakes. This design also makes it ideal for flood and ice rescue operations.

The airboat is pushed forward by the propeller, which produces a rearward column of air behind it. The resulting prop wash averages 150-mile-per-hour (241 km/h). Steering is accomplished by diverting that column of air left or right as it passes across the rudders, which the pilot controls via a "stick" located on the operator's left side. Overall steering and control is a function of water current, wind, water depth, and propeller thrust.

Stopping and reversing direction are dependent upon good operator/pilot/driver skills since airboats do not have brakes. They are incapable of traveling in reverse, unless equipped with a reversible propeller. Some designs use a clam shell reversing device intended for braking or backing up very short distances but these systems are not commonly used.

The operator/pilot/driver, and passengers in most instances, are seated in elevated seats that allow visibility over swamp vegetation. High visibility lets the operator and passengers see floating objects, stumps and animals in the boat's path.

History

The world's first flat-bottomed air boat was invented near Brigham City, Utah in 1943 by Cecil Williams, Leo Young, and G. Hortin Jensen.^[2] The purpose of the boat was to help preserve and protect bird populations and animal life work at the world largest migratory game bird refuge. The Bear River Migratory Bird Refuge near Brigham City, Utah is located as a wetlands oasis amid the great basin desert. It is an essential stopping point for migratory birds across North and South America. The need for a practical way to help navigate a challenging environment of wetlands, shallow water, and thick mud helped inspire, Cecil Williams, Leo Young, and G. Hortin Jensen to create the flat-bottom air thrust boat. Designs and subsequent improvements and practical use of the air thrust boats appears to have been a collaborative effort. Williams, Young, and Jensen were employees of the Bear River Migratory Bird Refuge, a division of US Fish and Wildlife Service.^[3] LeeRue Allen, who worked at the Refuge since 1936 appears to have also been involved and helped to document a history of the events.^[4][5]

The boat is on museum display at the Bear River Migratory Bird Refuge, near Brigham City, Utah and has also been on display at the National Conservatory Training Center in North Carolina. It has also been on display at the Black Bayou Lake Wildlife Refuge in Louisiana.^[6]

In 1943, on the Bear River Migratory Bird Refuge in northern Utah, Cecil S. Williams and G. Hortin Jensen sought a solution to the problem of conducting avian botulism studies in the shallow, marshy hinterlands. Using a 40-horsepower Continental aircraft engine on a 12-foot, flat-bottomed, aluminum boat, they came up with one of the world's first air boat designs. The original airboat had no seat and the pilot kneeled in the boat. They dubbed it the Alligator I. Today airboats are a popular mode of transportation for both researchers and tourists in wetlands around the world.^[7]

A 1987 story in Ducks Unlimited magazine mentioned Young and Jensen and dated the building of the first boat in 1950. Refuge records, however, show the first boat came into use in 1943, with several photos of running air boats dated 1947. Prior to the introduction of the airboat, refuge biologists had to either walk through shallow water and deep, sticky mud or push unpowered flat-bottom boats with long poles. Staff had experimented with a boat called the "Mud Queen," which had small paddle wheels on either side that pushed the boat. They built their first airboat nicknamed "Alligator I" from a flat-bottom boat pushed along by an aircraft engine purchased for $99.50. Young reported that he called the first airboat an "air-thrust boat." Once word got out about the boat, Leo Young built and sold boats all over the world.

Many of the early crafts built at the refuge were shipped to Florida. Early records show it cost roughly $1,600 to build a boat, including engine.^[8]

While a number of claims have been suggested about the invention and use of the first air boat, the most documuented, supported, verified of claims appears to be The world's first flat-bottomed air boat invented near Brigham City, Utah in 1943 by Cecil Williams, Leo Young, and G. Hortin Jensen. The practical value, use, and awareness of this first flat-bottomed air thrust boat quickly found wide use across the world.

Allegedly air plane motors were thought to have been tested using special boats. Allegedly one of the first of these types of "airboats", called the Ugly Duckling, was built in 1905 in Nova Scotia, Canada by a team led by Dr. Alexander Graham Bell. It was used to test various engines and prop configurations. This has not clearly been documented or supported nor have clear dates been verified and established.

Glenn Curtiss is credited with building a type of airboat in 1920 to help facilitate his hobby of bow and arrow hunting in the Florida backwoods. The millionaire, who later went on to develop the cities of Hialeah and Miami, combined his talents in the fields of aviation and design to facilitate his hobby, and the end result was 'Scooter', a 6-passenger, closed-cockpit, propellor-driven motorboat powered by an aircraft engine that could allegedly slip through wetlands at 50 mph.^[9][10]

Over the years a variety of designs were tried and through trial-and-error, the standard design used today arose: an open, flat bottom boat with an engine mounted on the back, the driver sitting in an elevated position, and a cage to protect the propeller from objects flying into them.

Here are some pictures of airboats.

An early form of the airboat

The Army Corps of Engineers uses an airboat to collect herbicide-resistant hydrilla from Lake Seminole in northern Florida

Manufacture

Airboat manufacturers tend to be small, family run businesses that assemble built-to-order boats. Airboats are also manufactured in Russia, Australia, Italy and Finland.

Modern, commercially manufactured airboat hulls are made of aluminum or fiberglass. The choice of material is determined by the type of terrain in which the vessel will be operated. Standard hunt/trail boats are 10-foot (3.0 m)-long with a two- to three-passenger capacity. Tour boats can be much larger, accommodating 18 passengers or more.

Engines are either an air-cooled, 4- or 6-cylinder aircraft or water-cooled, large-displacement, V8 automotive engine, ranging from 500 to over 600 horsepower (450 kW). Automotive engines tend to be less expensive due to readily-available replacement parts and less expensive High octane automotive gas. Since an opposed, 4- or 6-cylinder (O4 or O6) aircraft powerplant contains fewer moving parts than a standard automotive engine, it is easier to repair and weighs less. Most reciprocating aircraft powerplants can be derated to burn 87-octane automotive gas instead of more expensive aviation gas.

Most of the sound produced by an airboat comes from the propeller although the engine itself also contributes some noise. Modern airboat designs are significantly quieter thanks to mufflers and multi-blade carbon-fiber propellers.

Safety

Aft view of safety cage during operation

Knowledge of operational safety is essential when operating an airboat.

The engine and propeller are enclosed in a protective metal cage that prevents objects, e.g., tree limbs, branches, clothing, beverage containers, passengers, or wildlife, from coming in contact with the whirling propeller, which could cause devastating damage to the vessel and traumatic injury to the operator and passengers. If a tree branch gets into a propeller, the spray of material could be devastating, causing damage to the vessel and injury to the boat's occupants.

In 1998-99 the U. S. Fish & Wildlife Service's National Conservation Training Center, located in Shepherdstown, West Virginia, and in cooperation with the U. S. Corps of Engineers in Jacksonville, Florida, produced a 70-minute training video entitled Airboat Safety - Design-Operation-Maintenance. The video includes an early history of airboats and interviews with two airboat manufacturers in Florida. It was considered to be the only airboat video of its kind when it was made and may still be the only one with the range of airboat subject matter ever produced in the US. Since it was produced by a Federal Agency, it is in the public domain, and is not copyrighted. 500 copies of the video were produced.

Rescue

A resident is transported by Airboat after Hurricane Katrina.

U.S. Customs and Border Protection, Riverine Unit Patrols Rio Grande River Border in Air-Boat

In recent years, airboats have proven indispensable for flood, shallow water, and ice rescue operations. As a result, they have grown in popularity for public safety uses.

During the flooding of New Orleans following Hurricane Katrina, August 29, 2005, airboats from across the United States rescued thousands of flood victims. Thirty airboats evacuated over 3,000 patients and medical staff from four downtown New Orleans hospitals in less than 36 hours.

Numerous articles have been published in fire-rescue trade journals^[11] describing the advantages, capabilities, and benefits of using airboats for water rescue operations, and providing in-depth description of actual water rescue incidents, including the flooding of New Orleans.^{[12][13][14][15][16][17]}

Airboats are also used by U.S. Military, U.S. Coast Guard, and U.S. Border Patrol. During the Vietnam War the Hurricane Aircat airboat was used by the U.S. Special Forces to patrol areas where larger boats could not go.^[18] They are also used in Iraq and Texas for border patrol. The Nov/Dec 2007 issue of Airboating Magazine had an article on airboats used in Vietnam and in Iraq and has had numerous articles on airboats used by U.S Coast Guard and other state and county EMS units for rescue of ice fisherman and rescue in floods and after hurricanes.

See also

• Aerosani
• Hovercraft
• Hydrocopter
• Paddle steamer includes comment regarding animal drive ships
• Rotor ship, a same type of ship using a vertical "pipe" to propel the air

Notes

External links

• On the propulsion of ships by air propellers
• Italian racing "Idroscivolanti" of the 1930's