Editing Boat (section)

== Building materials ==
{{see also|Boat building}}
[[File:COLLECTIE TROPENMUSEUM Een Toba Batak prauw met houtsnijwerk op de voorsteven TMnr 60011149.jpg|thumb|Traditional Toba [[Batak]] boat ({{Circa|1870}}), photograph by [[Kristen Feilberg]]]]
[[File:Boats at Bhimili beach in Visakhapatnam.jpg|thumb|Fishing boats in [[Visakhapatnam]], India]]

Until the mid-19th century, most boats were made of natural materials, primarily wood, although  bark and animal skins were also used. Early boats include the [[birch bark]] [[canoe]], the animal hide-covered [[kayak]]<ref>{{cite book |last= Streever |first= Bill |title= Cold: Adventures in the World's Frozen Places |url= https://archive.org/details/coldadventuresin00stre |url-access= registration |location= New York |publisher= Little, Brown and Company |year= 2009 |page= [https://archive.org/details/coldadventuresin00stre/page/154 154]|isbn= 9780316042918 }}</ref> and [[coracle]] and the [[dugout canoe]] made from a single log.

By the mid-19th century, some boats had been built with iron or steel frames but still planked in wood. In 1855 [[ferro-cement]] boat construction was patented by the French, who coined the name "ferciment". This is a system by which a steel or iron wire framework is built in the shape of a boat's hull and covered over with cement. Reinforced with bulkheads and other internal structures it is strong but heavy, easily repaired, and, if sealed properly, will not leak or corrode.<ref>{{Cite book |last=Bingham |first=Bruce |url=https://www.worldcat.org/oclc/858712 |title=Ferro-cement: design, techniques, and application. |date=1974 |publisher=Cornell Maritime Press |isbn=0-87033-178-7 |location=Cambridge, Md. |oclc=858712}}</ref><ref>{{Cite web |title=Ferrocement – The World of Ferroboats |url=https://www.ferrocement.org/ |access-date=2022-12-26 |language=en-US}}</ref>

As the forests of Britain and Europe continued to be over-harvested to supply the keels of larger wooden boats, and the [[Bessemer process]] ([[patent]]ed in 1855) cheapened the cost of steel, steel ships and boats began to be more common. By the 1930s boats built entirely of steel from frames to plating were seen replacing wooden boats in many industrial uses and fishing fleets. Private recreational boats of steel remain uncommon. In 1895 WH Mullins produced steel boats of galvanized iron and by 1930 became the world's largest producer of pleasure boats.

Mullins also offered boats in aluminum from 1895 through 1899 and once again in the 1920s,<ref>WH Mullins boat history, Salem Ohio</ref> but it was not until the mid-20th century that [[aluminium]] gained widespread popularity. Though much more expensive than steel, aluminum alloys exist that do not corrode in salt water, allowing a similar load carrying capacity to steel at much less weight.

Around the mid-1960s, boats made of [[fiberglass]] (aka "glass fiber") became popular, especially for recreational boats. Fiberglass is also known as "GRP" (glass-reinforced plastic) in the UK, and "FRP" (for fiber-reinforced plastic) in the US. Fiberglass boats are strong and do not rust, corrode, or rot. Instead, they are susceptible to structural degradation from sunlight and extremes in temperature over their lifespan. Fiberglass structures can be made stiffer with sandwich panels, where the fiberglass encloses a lightweight core such as balsa<ref>.. as in the [[Iroqois]] [[catamaran]]</ref> or foam.

[[Strip-built|Cold molding]] is a modern construction method, using wood as the structural component. In one cold molding process, very thin strips of wood are layered over a form. Each layer is coated with resin, followed by another directionally alternating layer laid on top. Subsequent layers may be stapled or otherwise mechanically fastened to the previous, or weighted or vacuum bagged to provide compression and stabilization until the resin sets. An alternative process uses thin sheets of plywood shaped over a disposable male mold, and coated with epoxy.