Editing Block and tackle (section)

{{Short description|System of two or more pulleys and a rope or cable}}
[[File:Block-and-tackle-in-use.svg|thumb|200px|A "gun tackle" rove "to disadvantage"]]

A '''block and tackle'''<ref>"Tackle" can be {{IPAc-en|ˈ|t|eɪ|k|əl}} in this usage.</ref><ref>''{{Dead link|date=July 2022}}'' {{cite web |url=http://www.rcsccwarrior.ab.ca/Resources/Disc_Files/Resources/Phase_III/406_Seamanship/406.09_MLP.pdf |title=Royal Canadian Sea Cadets - Master Lesson Plan - Level T\\\2 |access-date=2009-12-27 |archive-url=https://web.archive.org/web/20130309060257/http://www.rcsccwarrior.ab.ca/Resources/Disc_Files/Resources/Phase_III/406_Seamanship/406.09_MLP.pdf |archive-date=2013-03-09 |url-status=dead }}</ref> or only '''tackle''' <ref>[https://archive.org/stream/manualofmilitary00grea/manualofmilitary00grea#page/n255/mode/1up Manual of military engineering]</ref> is a system of two or more [[pulley]]s with a [[rope]] or [[Wire rope|cable]] threaded between them, used to provide tension and lift heavy loads.

The pulleys are assembled to form [[block (sailing)|blocks]] and then blocks are paired so that one is fixed and one moves with the load. The rope is threaded through the pulleys to provide [[mechanical advantage]] that amplifies the force applied to the rope.<ref>Ned Pelger, [http://www.constructionknowledge.net/general_technical_knowledge/general_tech_basic_six_simple_machines.php ConstructionKnowledge.net]</ref>

[[Hero of Alexandria]] described cranes formed from assemblies of pulleys in the first century. Illustrated versions of Hero's ''Mechanica'' (a book on raising heavy weights) show early block and tackle systems.<ref>A. P. Usher, [https://books.google.com/books?id=xuDDqqa8FlwC&q=history+of+mechanical+inventions ''A History of Mechanical Inventions''], Harvard University Press, 1929 (Dover Publications, revised edition, 2011, {{ISBN|978-0486255934}})</ref>