Inflatable boat

An inflatable boat is a lightweight boat constructed with its sides and bow made of flexible tubes containing pressurised gas. For smaller boats, the floor and hull are often flexible, while for boats longer than 3 metres (9.8 ft), the floor typically consists of three to five rigid plywood or aluminium sheets fixed between the tubes, but not joined rigidly together. Often the transom is rigid, providing a location and structure for mounting an outboard motor.

Some inflatable boats can be disassembled and packed into a small volume, so that they can be easily stored and transported. The boat, when inflated, is kept rigid cross-ways by a foldable removable thwart. This feature makes these boats suitable for liferafts for larger boats or aircraft, and for travel or recreational purposes.

There are ancient carved images of animal skins filled with air being used as one-man floats to cross rivers. These floats were inflated by mouth.^{[citation needed]}

The discovery of the process to vulcanize rubber was made by Charles Goodyear in 1838, and was granted a US patent in 1844. Vulcanization stabilized the rubber, making it durable and flexible. In late 1843, Thomas Hancock filed for a UK patent, which was also granted in 1844, after the Goodyear Tire and Rubber Company patent had been granted. In 1852, while traveling in England, Charles Goodyear discovered that Thomas Hancock's company was producing vulcanized rubber and sued. Thomas Hancock had been shown a sample of Goodyear's rubber in 1842, but had not been told the process that made it—and Hancock said he had developed his process independently. The last of the suits were settled in 1855. Shortly thereafter, several people expanded on experimentation of rubber coated fabrics.

In 1839 the Duke of Wellington tested the first inflatable pontoons. In 1840, the English scientist Thomas Hancock designed inflatable craft using his new methods of rubber vulcanization and described his achievements in The Origin and Progress of India Rubber Manufacture in England published a few years later.

In 1844–1845, British naval officer Lieutenant Peter Halkett developed two types of inflatable boats intended for use by Arctic explorers. Both were made of rubber-impregnated "Mackintosh cloth." In the Halkett boat, the "boat cloak" served as a waterproof poncho or cloak until inflated, when it became a one-man boat. A special pocket held bellows for inflation, and a blade to turn a walking stick into a paddle. A special umbrella could double as a sail. Halkett later developed a two-man boat carried in a knapsack. When inflated, it could carry two men paddling on either side, and when deflated it served as a waterproof blanket for camping on wet ground. The Admiralty was sceptical about potential uses for Halkett's designs; on 8 May 1845, Lord Herbert, First Secretary to the Admiralty, wrote to Halkett that "My Lords are of an opinion that your invention is extremely clever and ingenious, and that it might be useful in Exploring and Surveying Expeditions, but they do not consider that it would be made applicable for general purposes in the Naval Service".

The Admiralty saw no use for Halkett's designs in general naval service, but explorers liked this larger design. John Franklin bought one for the ill-fated 1845 expedition, in which the entire expedition party of 129 men and two ships vanished.

In his explorations along the Oregon Trail, and the tributaries and forks of the Platte River in 1842 and 1843, John C. Frémont recorded what may have been the first use of an inflatable rubber boat for travel down rivers and rapids in the Rocky Mountains. In his account of the expedition he described his boat: