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