This document specifies the types, nominal sizes, dimensions and materials, as well as construction, manufacturing and marking requirements, for Panama chocks installed to lead the mooring and towing rope of a ship. It is intended for ships passing through the Panama Canal, which are normally assisted through the locks by locomotives using steel towing wires and/or by tug boats. These chocks meet normal mooring requirements and Panama Canal requirements; they are suitable for mooring vessels inside the Panama Canal locks.