| A wide variety of materials and | | | | foam or similar material is applied |
| materials are used in boat building: | | | | after the outer layer of fiberglass is |
| Wood - The traditional boat building | | | | laid to the mold, but before the inner |
| material that was and is still used for | | | | skin is laid. This is similar to the |
| hull and spar construction. It is | | | | next type, composite, but isn't usually |
| buoyant, cheap, widely available and | | | | classified as composite, since the core |
| easily worked. It is not particularly | | | | material in this case doesn't provide |
| abrasion resistant and it can | | | | much additional strength. It does, |
| deteriorate if fresh water or marine | | | | however, increase stiffness, which means |
| organisims are allowed to penetrate the | | | | that less resin and fiberglass cloth can |
| wood. Rot resistant woods such as cedar | | | | be used in order to save weight. Most |
| and oak are generally selected for | | | | fiberglass boats are currently made in |
| wooden boat construction. Glue, screws | | | | an open mold, with fiberglass and resin |
| and/or nails are used to join the wooden | | | | applied by hand. Some are now |
| components. Some types of wood | | | | constructed by vacuum infusion where the |
| construction include: | | | | fibers are laid out and resin is pulled |
| Carvel, in which a smooth hull is formed | | | | into the mold by admospheric pressure. |
| by wooden planks attached to a frame. | | | | This can produce stronger parts with |
| The planks may be curved in cross | | | | more glass and less resin, but takes |
| section like barrel staves. Carvel | | | | special materials and more technical |
| planks are generally caulked with oakum | | | | knowledge. |
| or cotton that is driven into the seams | | | | Composite - While GRP, wood, and even |
| between the planks and covered with some | | | | concrete hulls are technically made of |
| water proof substance. It takes its name | | | | composite materials, the term |
| from an archaic ship type and is | | | | "composite" is often used for plastics |
| believed to have originated in the | | | | reinforced with fibers other than (or in |
| Mediterranian. | | | | addition to) glass. Cold-molded refers |
| Another method of building wooden boats | | | | to a type of building one-off hulls |
| is lapstrake, a technique originally | | | | using thin strips of wood applied to a |
| identified with the Vikings in which | | | | series of forms at 45-degree angles to |
| wooden planks are fixed to each other | | | | the centerline. This method is often |
| with a slight overlap that is beveled | | | | called double-diagonal because a minimum |
| for a tight fit. The planks may be | | | | of two layers is recommended, each |
| mechanically connected to each other | | | | occurring at opposing 45-degree angles. |
| with copper rivets, bent over iron | | | | "Cold-molding" is now a relatively |
| nails, screws or with adhesives. Often, | | | | archaic term because the contrasting |
| steam bent wooden frames are fitted | | | | "hot-molded" method of building boats, |
| inside the hull. This technique is known | | | | which used ovens to heat and cure the |
| as clinker in Britain and also as clench | | | | resin, has not been widely used since |
| built. | | | | WWII. Now almost all curing is done at |
| Another method uses sheets of plywood | | | | room temperature. Other composite types |
| panels fixed to a frame. Plywood may be | | | | include sheathed-strip, which uses |
| laminated into a round hull or used in | | | | (usually) a single layer of strips laid |
| single sheets. These hulls generally | | | | up parallel to the sheer line. The |
| have one or more chines. A type of the | | | | composite materials in question are then |
| plywood panel boat building methond is | | | | applied to the mold in the form of a |
| known as the stitch-and-glue method, | | | | thermosetting plastic (usually epoxy, |
| where pre-shaped panels of plywood are | | | | polyester, or vinylester) and some kind |
| edge glued and reinforced with | | | | of fiber cloth (fiberglass, kevlar, |
| fibreglass without the use of a frame. | | | | dynel, carbon fiber, etc), hence the |
| Metal or plastic wires pull curved flat | | | | finished hull is a "composite" of fiber |
| panels into three dimensional curved | | | | and resin. These methods often give |
| shapes. These hullls generally have one | | | | strength-to-weight ratios approaching |
| or more chines. | | | | that of aluminum, while requiring less |
| Steel (and before that iron) - Either | | | | specialized tools and skills. |
| used in sheet for all-metal hulls or for | | | | Steel-reinforced cement (ferrocement) - |
| isolated structural members. It is | | | | Strong and long lasting. First developed |
| strong, but heavy. The material rusts | | | | in the mid 19th Century in France. Used |
| unless protected from water. Modern | | | | for building warships during the war. |
| steel components are welded or bolted | | | | Extensively refined in New Zealand |
| together. Until the mid 1900s, steel | | | | shipyards in the 1950s and the material |
| sheets were riveted together. | | | | became popular among amateur builders of |
| Aluminium - either used in sheet for | | | | cruising sailboats in the 1970s and |
| all-metal hulls or for isolated | | | | 1980s, because the material cost was |
| structural members. Many sailing spars | | | | cheap although the labour time element |
| are made of aluminium. The material | | | | was high. The weight of a finished |
| requires special manufacturing | | | | ferro-cement boat is comparable to that |
| techniques, construction tools and | | | | of a traditionally built wooden boat. As |
| construction skills. While it is easy to | | | | such they are often built for slower, |
| cut, aluminium is difficult to weld, and | | | | more comfortable sea passages. Hulls |
| also requires heat treatments such as | | | | built properly of ferrocement are more |
| precipitation strengthening for most | | | | labor-intensive than steel or |
| applications. Corrosion is a concern | | | | fiberglass, so there are few examples of |
| with aluminium, particularly below the | | | | commercial ship-yards using this |
| waterline. | | | | material. The inability to mass produce |
| Fiberglass (Glass-reinforced plastic or | | | | boats in ferro cement has led there to |
| GRP) - Typically used for production | | | | being few examples around. Many |
| boats because of its ability to reuse a | | | | ferrocement boats built in back yards |
| female mold as the foundation for the | | | | have a rough, lumpy look, which has |
| shape of the boat. The resulting | | | | helped to give the material a poor |
| structure is strong in tension but often | | | | reputation. The ferro-cement method is |
| needs to be either laid up with many | | | | easy to do, but it is also easy to do |
| heavy layers of resin-saturated | | | | wrong. This has led to some disastorous |
| fiberglass or reinforced with wood or | | | | 'home-built' boats. Properly designed, |
| foam in order to provide stiffness. GRP | | | | built and plastered ferrocement boats |
| hulls are largely free of corrosion | | | | have smooth hulls with fine lines, and |
| though not normally fireproof. These can | | | | therefore are often mistaken for wooden |
| be solid fiberglass or of the sandwich | | | | or fiberglass boats. |
| (cored) type, in which a core of balsa, | | | | |