Portsmouth Block Mills in 1808. The machines were of 22 types and totalled 45. They were driven by two 30 hp (22.4 kW) steam engines. The machines included circular saws, pin turning machines and morticing machines. With these machines 10 men could produce as many blocks as 110 skilled craftsmen. A pulley-block has four parts: the shell, the sheave, the pin for locating the latter in the shell and a metal bush, or coak, inserted into the sheave to save wear between it and the pin. Blocks can vary in size and in the number of sheaves. The process of making the shells
Cargo hook (helicopter) metal at the bottom of a cargo hook that supports the load. Usually it has a curved, narrow end which is used to load a ring, rope, or net onto the hook. The keeper is the locking, spring-operated mechanism that keeps the load from sliding off the load beam during transport. The attach point attaches the hook to the belly of the helicopter, swing system, or longline. The following table includes a list of helicopter models that are designed to carry underslung loads. Cargo capacities provided reflect the airframe manufacturer's specifications; when put into practice the actual maximum load capacities