What is the requirement when machines are used in the hatch during loading or unloading operations?

The correct choice states that manual work is not required by operating machines. In the context of loading and unloading operations in maritime or shipping environments, technological advancements allow machines to perform tasks that were traditionally done manually. This means that machines can efficiently handle many processes without the need for constant human intervention during their operation.

The rationale for this is rooted in improving workplace efficiency and safety, as machines often have capabilities designed specifically for handling heavy loads and performing repetitive tasks that might be dangerous or strenuous for humans. Thus, when machines are utilized in the hatch during loading or unloading, the reliance on human labor for manual input is reduced, which can lead to faster operations and minimize the risk of injury.

While skilled workers are necessary to operate machines effectively and safely, and there may be scenarios where human oversight is required to ensure proper operation, the fundamental requirement set by the question is focused on the ability of machines to function autonomously in these situations.