How does the angle of repose influence the design of cargo holds for specific bulk cargo?

The angle of repose, which is the steepest angle at which a pile of granular material will remain stable, directly influences the design of cargo holds for specific bulk cargoes because it affects the stability of the cargo and the ship. A higher angle of repose indicates a material that tends to form steeper piles and is less likely to shift, while a lower angle of repose signifies a more fluid material that spreads out and is more prone to shifting during transit. Cargo holds for materials with low angles of repose, like grain or certain ores, require features to prevent shifting. These features include longitudinal divisions, also known as shifting boards, which divide the hold into smaller compartments to limit the distance the cargo can move. This reduces the potential for the ship to develop a dangerous list, which is a sideways tilt. The design must also ensure adequate filling of the holds, as partially filled holds with low angle of repose cargo are highly susceptible to shifting. Conversely, materials with high angles of repose, such as some types of coal or mineral concentrates, may not require extensive shifting boards, but the hold design must still account for the pressure exerted by the cargo on the hold's boundaries. Furthermore, the shape of the hold, particularly the sloping of the sides, can be optimized to match the angle of repose, minimizing void spaces and maximizing cargo capacity while maintaining stability. Understanding the angle of repose is therefore crucial for designing cargo holds that ensure both safe and efficient transport of bulk cargoes, considering the specific properties of the material being carried.