Which tensioning system would require the least amount of manpower from the choices given?

The tensioning system that requires the least amount of manpower is a 6:1 system. This type of mechanical advantage means that for every unit of effort applied, the load is lifted six times that amount. As a result, the rescuer can exert a smaller effort to achieve a greater lifting force on the load, minimizing the physical effort and manpower needed to operate the system effectively.

In high-angle or technical rescue scenarios, reducing manpower is crucial as it helps in managing resources and maintaining team safety and efficiency. With a 6:1 advantage, fewer rescuers are needed to manage the tensioning process, allowing teams to focus on other critical aspects of the rescue operation.

Lower mechanical advantage systems, such as 1:1 or even 2:1 and 3:1, require more effort and manpower to accomplish the same lift compared to a 6:1 system. This makes them less efficient in scenarios where exertion and personnel resources must be conserved.