This mobile sheave block is designed for situations in which a stationary foot block is inadequate, such as when peeling spinnakers or adjusting a sheet winch. It is easily attached using a webbing strop and can be positioned on a toe rail or padeye without the need for drilling, making it a clutter-free option for deck use. The plain bearing sheave ensures smooth operation under low loads, while also providing exceptional durability under high loads. The attached strop allows for maximum rotation when using the spinnaker sheet, and the CAM offers three distinct operating modes for ultimate control.