Z-drag

Z-drag

A Z-Drag is an arrangement of lines and pulleys commonly used in rescue situations. The arrangement provides a mechanical advantage of three. The name comes from the fact that the arrangement of lines is roughly Z shaped.

The typical configuration (shown below) uses two pulleys and two Prusik knot loops (sliding/gripping knots). The first Prusik knot provides the mechanical advantage. The second Prusik knot can be used to hold the position of the rope and is sometimes referred to as a 'progress capture device.' At least two people are usually needed to operate a Z-Drag since the Prusik knots require periodic adjustment. It is also advisable to attach a towel or soft object (such as a life vest) to the end of the line near the connection to the object being pulled since the line is under high tension and could break free and present a dangerous flying hazard.

The Z-Drag is considered an important tool in whitewater rescue and is used primarily for the recovery of pinned boats.

References

* Swiftwater Rescue: A Manual for the Rescue Professional ISBN 978-0964958500
* Whitewater Rescue Manual: New Techniques for Canoeists, Kayakers, and Rafters ISBN 978-0070677906
* River Rescue: A Manual for Whitewater Safety ISBN 978-1878239556


Wikimedia Foundation. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Drag Me to Hell — Theatrical poster Directed by Sam Raimi Produced by Gr …   Wikipedia

  • Drag racing — Drag racer and Drag race redirect here. For other uses, see Drag racing (disambiguation). The Christmas tree counting down at SIR. Note the blinder, to prevent the driver from being distracted by the light for the other lane. Drag racing is a… …   Wikipedia

  • Drag-On — Saltar a navegación, búsqueda Drag On Información personal Nombre real Mel Jason Smalls Nacimiento 4 de enero de 1979 (30 años) Orige …   Wikipedia Español

  • drag — queen [ dragkwin ] ou drag [ drag ] n. f. • v. 1990; empr. angl., de to drag « traîner », à cause de la robe longue, et queen « reine » ♦ Anglic. Travesti masculin vêtu de manière recherchée et exubérante. Des drag queens. ● drag nom masculin… …   Encyclopédie Universelle

  • Drag queen — Saltar a navegación, búsqueda en:Miss Understood by David Shankbone Reinona o Drag queen es un hombre o mujer que se viste y actúa como una mujer exageradamente, de forma provocativa y para dar …   Wikipedia Español

  • drag — DRAG, Ă, dragi, e, adj., subst. I. adj. 1. Care este iubit, scump, nepreţuit pentru cineva, pe care cineva îl iubeşte, îl preţuieşte. ♢ loc. vb. A prinde drag (de cineva) = a se îndrăgosti (de cineva). ♢ expr. A i fi cuiva drag să... = a i plăcea …   Dicționar Român

  • Drag Strip — is the name of a fictional character in the Transformers universes.Transformers: Generation 1Transformers character name =Dragstrip japanname = caption =Drag Strip in animated form affiliation =Decepticon subgroup =Deluxe Vehicles, Stunticon rank …   Wikipedia

  • drag — /drag/, v., dragged, dragging, n., adj. v.t. 1. to draw with force, effort, or difficulty; pull heavily or slowly along; haul; trail: They dragged the carpet out of the house. 2. to search with a drag, grapnel, or the like: They dragged the lake… …   Universalium

  • Drag Ball — St. Louis was created by Khrystal Leight, a zaftig Bette Midler impersonator from St. Louis, to entertain and raise awareness of the art form of female impersonation in local and regional college campuses throughout the Midwest. Drag Ball was… …   Wikipedia

  • Drag (k.d. lang album) — Drag Studio album by k.d. lang Released June 10, 1997 (1997 06 10) …   Wikipedia

  • Drag King — Un groupe de Drag Kings se produisant en spectacle Les Drag kings sont des personnes (hommes, femmes ou autres selon leur autodétermination) construisant une identité masculine volontairement basée sur des archétypes de façon temporaire le temps… …   Wikipédia en Français

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”