The application and research of U-shaped shackle

On the flat sections of the ship's hull, there are numerous straight plate sections, typically made of bulb flats, with weights ranging from approximately 20 to 60 tons each. Usually, the lifting of these plate sections involves the installation of 4-8 lifting slings to assist in hoisting. However, the installation and removal of these slings not only incur labor and material costs but also result in low operational efficiency.

The Long U-shaped shackle serves as a typical successful case of new tool research and application to address the lifting issues of these flat plate sections. Through the study of the structural forms of ship hull plate sections, it was found that bulb flats are often used as the structural material, with bulb flat sizes ranging from HP120 to HP430. The drainage holes and vent holes on the bulb flats are typically designed to have a height of 50mm to 75mm.

Based on these structural characteristics, a Long U-shaped shackle was designed to be directly installed in the drainage or vent holes of the bulb flats, enabling quick and safe lifting of the plate sections. This innovation is pioneering in China. The Long U-shaped shackle is shown in Figure 3, and its on-site application is depicted in Figure 4.

The advantages of the Long U-shaped shackle include low cost, with each unit costing only a few hundred yuan; lightweight design, allowing for direct installation on the structure, lightweight and quick; high safety, as the lifting shackle is installed on a sturdy structure, making it safer than plate clamps; simple management, compatible with existing lifting gear management systems; and eliminating the need for welding, removal, and repair operations, while also being reusable.

The first application of the Long U-shaped shackle in the maritime industry provides a safe, convenient, efficient, and durable solution for lifting plate sections made of bulb flats with drainage holes. By using the Long U-shaped shackle for lifting, the number of lifting slings required is reduced, significantly improving lifting efficiency, reducing the workload for operators, and saving costs for the company.