The materials utilized in the field of boat building have advanced during the times from the most common unrefined components accessible in nature like wood to the latest cutting-edge composites like carbon and Kevlar, which are at present moving in the business sectors.
There are different materials from which boats are fabricated and of which the primary ones are wood, aluminum, composites, and steel.
The primary aspect a yard/builder searches for is what materials are reasonable for their prerequisites. For instance, on the off chance that the yard is wanting to sell out production line boats, they ordinarily go with fiberglass as they will have a preset form out of which they can continue to print comparable models.
Whereas, in the event of custom-built different materials like wood, aluminum is used where they need to independently manufacture the frame, liner, and superstructure.
In this article, we will perceive the way the wheel of advancement in boat-building materials began to turn, the way things are going at present, and where it is going towards the future.
Wood and Marine Plywood
Wood was the material that was utilized principally in boat building during the old days until the 1900s after which different materials began arising in the bat building market. With regards to wood, the sort of wood utilized in boat building is various types utilized in different parts of the world.
Here, we are featuring a portion of the unmistakable ones utilized in conventional boat building like Teak, Oak, Cedar, Pine, Mahogany, and significantly more. Not only do they change from their appearance, but they also have a tremendous distinction in their mechanical properties likewise regarding strength, thickness, etc.
A more normal kind of wood utilized as far as usefulness and achievability is marine-grade plywood. Marine compressed wood is produced using Western Larch or Douglas Fir wood and has at least 5 layers bonded to one another with WBP (Weather Boil Proof) adhesive, having more modest voids than standard compressed wood and a lot lesser air entrapment.
Types of Marine Plywood
The three main types classified as per classification society are:
- BS 1088
- BS 6566
- AS/NZ 2272
Production methods in boat building
Strip planking is the most widely recognized strategy embraced by builders, frames are set up with characterized spacings and wood sheets are appended along with the frames which fundamentally makes the external shell/plate of the vessel.
This strategy isn’t just utilized in making frames yet in addition for various areas, for example, wheelhouse and superstructure. Here are the pros and cons of marine-grade plywood.
Water-resistant, Flexible, Durable, Uniform strength, High density, Easily available
Not 100% waterproof, reacts to chemicals, can bend when overloaded
Aluminum came up in the boat-building industry during the mid-1960s when manufacturers got going to carry out the material on smaller boats. The utilization of aluminum gave the manufacturer much more flexibility in the build as it was extremely simple to twist and shape with the current instruments utilized on wood.
The vital attributes of the material were that it was lightweight, water-resistant, corrosion-free, economical, and had a high strength-to-weight ratio.
Types of Aluminum
Although pure aluminum has good corrosive resistance, continuous use in the marine environment can degrade its properties, and hence to enhance them Marine grade Aluminum is introduced.
Marine-grade Aluminum is alloyed with other metals like magnesium giving rise to a product that is highly corrosive resistant. The commonly used types are:
All the above have varying mechanical and physical properties and are used for specific applications in the marine environment.
Production Methods In Boat Building
With Aluminum, it is easy to perform activities such as cutting, welding, drilling, and so on during the building process making it very easy for the handlers during the build. Here are the pros and cons of aluminum:
High strength-to-weight ratio, rust-proof, easy to work with, easily available, maintenance-friendly, small boats tend to be cheaper
Large boats tend to be more expensive, underwater protection is needed such as antifouling paint, anodes, and more noise from the impact of water on the hull.
Composites In Used For Boats
Composites or fiber-reinforced plastics, in straightforward terms are those materials that are formed when two individual materials combine with one another to form a solitary material that is more grounded in mechanical properties than the individual materials.
Out of the two materials, one behaves like an underlying material that provided the structural strength called fiber (glass, carbon, aramid) and the other is one that keeps the fibers intact called a matrix (polyester, vinyl ester, epoxy, and so forth.)
The matrix and fibers are utilized in different combinations, which gives out a specific mechanical property for a specific application. Other than matrix and fibers composites additionally contain certain materials like core materials, fillers, adhesives, and so on to upgrade the physical and mechanical properties of the final product.
Type Of Composite Fibers
We have a detailed comparison of glass fiber vs carbon fiber in this article, but here is a quick and basic overview of composite fiber types.
- Glass Fibers
Most usually utilized and the least expensive of all fibers. They are regularly accessible in types of CSM (Chopped Strand Mats), woven roving, biaxial, quadriaxial, and uni-directional to use the strength of the filaments in unambiguous directions.
Further Glass filaments are separated into E-glass and S-glass. S-glass is more grounded and more costly than E-glass and is for the most part utilized in military applications and its business accessibility is restricted.
Otherwise called graphite fiber. It is comprised of a number of strands of carbon that are utilized to reinforce the material. It is additionally wound to shape yarns from which it is made into a cloth material. The quantity of strands of carbon decides its solidarity, 1K, 3K, 6K, 12K, 24K, 50K, and others are normal bundle sizes where k signifies 1000 strands.
Aramid is a polyamide that gives exceptional flexibility and impact resistance, utilized fundamentally for ballistic protection & impact resistance, and can be mostly seen as a protective layer on bulletproof vests. While less firm than carbon, aramid is stiffer and a lot lighter than glass.
Types of Composite Resins
Resins are broadly classified into thermoplastics and thermosetting. In marine applications, we mainly used thermosetting resin, which is further classified into:
- Vinyl Ester
Production methods in boat building
The main application methods currently being used in the industry are as follows.
- Hand/wet Layup
Hand layup (or wet layup) is a process where the laminator manually applies the matrix and the fibers and is left to cure.
- Vacuum bag wet layup
A vacuum bag is a process where the laminator manually applies the matrix and the fibers, and rather than leaving it to cure, a vacuum is applied over the area under a bag which helps in removing the excess resin
In this process, the fibers are laid and a vacuum is applied to the dry fibers with the help of bags you then allow the pressure difference between the inside of the bag and the resin kept outside in a pot to suck the resin and feed through the dry laminate, making it wet.
Pre pregs are presoaked fibers with a matrix that are stored at cold temperature and applied onto a mold surface, further treated with heat (mostly in an oven) to make it cured. Here are the pros and cons of composite resins.
Lightweight, higher strength-to-weight ratio, easy maintenance, no corrosion,
Non-recyclable, more expensive, can crack during collisions.
The decision of what material a builder/yard chooses directly depends on the purpose of the vessel and the requirements of the end-user, the owner. These aspects along with how the product affects the environment in the future should be kept in mind by the builders and choose the most ideal option for building the boat.