Discharging Timber from an Angle: Ensuring Safety and Stability for Berthed Ships

When a ship is berthed at an angle, it is crucial to discharge cargo, particularly timber, carefully to ensure the vessel's stability and safety. This article explores the correct procedure for discharging timber on deck when the ship is berthed at an angle that causes it to roll away from the quay.

Understanding the Angle of Rolling

When a ship is berthed at an angle, it can experience an angle of rolling. This phenomenon is different from the angle of loll, which occurs when the center of gravity (G) and the metacenter (M) coincide, leading to a zero or negative GM (metacentric height). An angle of loll is a hazardous condition as it can result in the ship flipping over. In contrast, when a ship is berthed at an angle, the goal is to maintain stability and prevent further rolling.

Discharging Timber from the Higher Side

To ensure stability and safety, timber on deck should be discharged from the side that is higher or farthest from the quay. This approach is particularly important for the following reasons:

Stability

The primary reason for discharging timber from the higher side is to reduce the ship's heel, which is the angle at which the ship tilts away from the quay. If timber is discharged from the lower side, it can exacerbate the ship's rolling motion, increasing the risk of capsizing or causing the ship to roll further away from the dock. By releasing cargo from the higher side, you help to balance the weight distribution and maintain a stable stance.

Weight Distribution

Removing weight from the higher side first ensures a more even weight distribution on the ship. This is crucial in preventing further rolling and ensuring the ship remains stable throughout the unloading process. By maintaining an even weight distribution, you minimize any lateral forces that can cause the ship to tilt or roll.

Safety

Discharging from the higher side also reduces the risk of the cargo falling or shifting unexpectedly. This is particularly important for the safety of the crew and the vessel. Any sudden movement or shift in the timber can be dangerous, especially if it occurs near the waterline or during critical moments in the unloading process.

Conclusion

In conclusion, timber on deck should be discharged from the side that is higher or farther from the quay to maintain stability, ensure safe unloading, and prevent further rolling of the ship. By following these precautions, you can ensure a smooth and safe unloading process, minimizing the risk of accidents and structural issues.

Proper management of the ship's stability is crucial in maritime operations. Understanding the principles of stability and applying them in practice can significantly reduce the risks associated with berthing and unloading operations.