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
Miztec (schooner barge) the State of Michigan after they were seized in a 1992 Michigan Department of Natural Resources and Environment (DNRE) raid on the Great Lakes Shipwreck Museum. The State allows the museum to hold a triple sheave block and hook and a double sheave block and hook from the "Miztec" as a loan. Her wreck is now protected by the Whitefish Point Underwater Preserve as part of an underwater museum. The 194 foot wooden "Miztec" was built as a 3-masted schooner in 1890 in Marine City, Michigan. She was enrolled at Port Huron, Michigan on 8 April 1890. On 3 May