The ancients used coarse cloth and hemp as raw materials to make fishing nets through bundling. Let's take a look at the introduction and types of fishing nets.
With the development of fisheries, the objects of fishing and hunting are not only fish, but fishing tools are also advancing with the times. Modern fishing nets are mainly processed with raw materials such as polyethylene and nylon. It has a longer service life and higher fishing efficiency, so it can be classified according to different usage methods. For example, traditional fishing nets (hand nets, hand-throwing nets), boat-powered trawl nets, and gill nets with different meshes (three nets, seine nets) for lure fishing and so on. These nets are woven with different mesh sizes and different materials for different fishing objects. At the same time, with the development of fishing nets, various fishing tools have emerged, such as fish cages and four-corner nets. These are fishing tools that people often use.
If fishing nets are used as catching and breeding tools, they have more uses, such as sticky nets for catching birds, purse nets in aquaculture, breeding tanks, and so on. In agricultural planting, "fishing nets" are also widely used and are often used as disposable tools. For example, flower cultivation in the Netherlands. In safety protection and sports, "fishing nets" are widely used. In sports, the most typical example is tennis, as the name suggests. Safety protection, such as construction site protection net, elevator protection net. It is understood that a foreign company provides a complete set of protection network solutions for large warehouses. It not only protects workers but also improves transportation efficiency. In short, fishing nets (fishing nets) not only inherit their ancient uses, but also play a wide range of roles in agriculture, sports, and safety protection.
The nets used in fishery production include trawl nets, purse nets, cast nets, fixed nets and cages. Trawling and purse nets are heavy nets for marine fishing. The mesh size is 2.5 ~ 5 cm, the rope diameter is about 2mm, and the net weight is several tons or even 10 tons. Ping often uses a pair of tugboats to chase the fish separately, or uses light boats to lure the fish into groups. Casting nets are light nets used for fishing in rivers and lakes. The mesh size is 1 ~ 3 cm, the diameter of the mesh rope is about 0.8 mm, and the mesh weight is several kilograms. Fixed nets and cages are fixed nets for artificial breeding in lakes, reservoirs or bays. The size and specifications are different according to the fish to be cultured, and fish cannot escape from being cultured in certain waters.
The main raw materials for woven fishing nets are 15 ~ 36 strands of 210 denier nylon, polyester multifilament and 380 denier polyethylene multifilament. Weaving methods include knotting, twisting and warp knitting.
Knotting
This is the traditional method of making fishing nets. The fishing net is made from the warp and weft in the shuttle. The node is 4 times the diameter of the net rope and protrudes from the plane of the net. This kind of netting is called netting (Figure 1, a). When the net is lifted, the nodules collide with the fish and the ship's rail, which not only damages the fish but also wears the net. Because chemical fiber is smooth and elastic, it is easy to cause problems such as loose nodules and uneven mesh.
Twisting method
The two sets of yarns are twisted simultaneously by the machine and cross each other to form a net at the crossing point. This kind of net is called a twisted no-knot net. Because the yarn at the knots does not undergo twists and turns, the net becomes flat and the friction is reduced, but the efficiency of the twisting machine is low, the preparation process is complicated, and the horizontal net is limited, so it is only suitable for weaving nets with larger meshes.
Warp knitting method
Usually, a warp knitting machine with 4 to 8 yarn guide rods is used to connect the warp yarns into a net, which is called a warp knitting no knot net (Figure 2). Due to the high speed of the warp knitting machine (600 rpm), the width of the weaving mesh is wide, the number of dazzling eyes can reach more than 800, the change of specifications is convenient, and the production efficiency is several times higher than the previous two methods. The warp-knitted non-knotted net is flat, wear-resistant, lightweight, stable in structure, high in knot strength, and will not deform or loose after breaking. It can be widely used for special purposes such as offshore fishing, freshwater fishing and aquaculture.