BHC Line Test On Board: A Comprehensive Guide
- Understanding the significance of the BHC line test on board.
- The procedure and components involved in the BHC line test.
- Real-world examples and applications of the BHC line test.
- Common questions and misconceptions about the BHC line test.
What is the BHC Line Test?
The BHC (Brake Holding Capacity) line test is a crucial procedure conducted on ships to ensure the safety and functionality of the winch brake system. This test is essential as it determines the brake’s ability to hold a specific force without slipping. In the maritime industry, ensuring that the winch brake system operates effectively is paramount to prevent accidents and ensure smooth operations.
Components and Procedure of the BHC Line Test
Winch Brake Test Form (BHC) Rendering
The BHC line test involves several components and measurements that are crucial for its accuracy:
- Winch Position Number: This indicates the specific winch being tested, such as FWD PORT (No. 1), FWD STBD (No. 2), and so on.
- R (cm): Distance between the center of the drum and the first layer of rope.
- D (cm): Distance between the center of the drum and the jack.
- P (kg/cm2): Pressure reading when the drum begins to drift. This must be read-off during the test.
- Brake Capacity (Tons): This is the result of the calculations based on the above measurements.
Understanding the Measurements
- Column (1) R: This measures the distance between the center of the drum and the first layer of rope.
- Column (2) D: This measures the distance between the center of the drum and the jack.
- Column (3) P: This is the pressure reading taken when the drum starts to drift. It’s essential to capture this reading during the test.
- Column (4) Brake Holding Force: This is calculated using the formula: Brake Holding Force=�×(3)×(2)=TONS×(1)×1000Brake Holding Force=A×(3)×(2)=TONS×(1)×1000 Where A is the piston area of the jack, given in the jack specification in cm^2.
Real-World Application: A Worked Example
Consider a scenario where the distance D (i.e., the distance between the center of the drum and the jack) is 59 cm, and R (i.e., the distance between the center of the drum and the first layer of rope) is 17 cm.
Once these measurements for D(cm) and R(cm) have been taken, and the brake screw tightened, the force applied by the jack may be gradually increased. If the pressure reading just before the brake begins to slip is, for instance, P = 160 kg/cm^2 and assuming that the piston area of the jack, as in the case of the “EIRINI L”, is A = 44.2 cm^2, then the Brake Holding Force in TONS can be calculated as: �(����)=44.2×220×5917.0×1000=33.74TONSF(TONS)=17.0×100044.2×220×59=33.74TONS
This result in Column 4 should match the required brake force. A mark is then attached to the brake screw handle, indicating the degree to which the brake handle screw must be fastened to achieve the necessary brake force. If the result in column 4 differs from the required force, the brake can be readjusted, and the test repeated until the necessary brake force is achieved, and the corresponding screw tightness marked.
Common Misconceptions and Clarifications
Why is the BHC Line Test Essential?
The BHC line test is not just a procedural requirement but a critical safety measure. It ensures that the winch brake system can hold the necessary force, preventing potential accidents and ensuring smooth operations on board.
How Often Should the BHC Line Test be Conducted?
The frequency of the BHC line test varies depending on the vessel’s operational requirements and the maritime regulations of the region. However, it’s generally recommended to conduct the test at regular intervals to ensure the winch brake system’s optimal performance.
What Happens if the Brake Holding Force Doesn’t Match the Required Force?
If the brake holding force doesn’t match the required force, it indicates that the winch brake system may not hold the necessary force during operations. This can lead to potential accidents. In such cases, the brake system must be readjusted and the test repeated until the required force is achieved.