What are the specialized securement requirements when transporting heavy cylindrical cargo (such as steel coils / 钢卷 or large industrial pipes) on a flatbed semi-trailer?

1. Must use heavy concave cradles/chocks, high-friction rubber mats, high-tensile grade-80+ chains with ratchet binders passing over and through the core, and longitudinal blocking
2. Tie the 20-tonne steel coil with a single thin nylon rope to the side mirror bracket
3. Rely entirely on the weight of the steel coil to keep it in place without any chains
4. Grease the trailer deck thoroughly so the steel coil can slide smoothly during turns