Long loads should ideally be handled by which type of below the hook lifting device?

Using a spreader beam for handling long loads is ideal due to its design, which distributes the load evenly across multiple lifting points. This helps to maintain stability and minimizes the risk of the load tipping or swinging during the lift. The spreader beam's configuration allows it to handle the load more safely and efficiently by preventing excessive stress on the load and the lifting equipment.

In contrast, a chain hoist typically lifts loads vertically but does not provide the necessary stability for longer items. A hook block is mainly used for connecting multiple hoists, without the same load distribution benefits. Lastly, while a plate clamp is effective for lifting flat materials, it does not offer the same level of support for long loads as a spreader beam does. The spreader beam's design is specifically tailored for such applications, making it the best choice for handling long loads safely.