Block (sailing)

Block (sailing)

In sailing, a block is a single or multiple pulley. One or a number of "sheaves" are enclosed in an assembly between "cheeks" or "chocks". In use a block is fixed to the end of a line, to a spar or to a surface. Rope or line is "rove" through the sheaves, and maybe through one or more matching blocks at some far end to make up a tackle.

The "purchase" of a tackle refers to its mechanical advantage. In general the more sheaves in the blocks that make up a tackle, the higher its mechanical advantage. The matter is slightly complicated by the fact that every tackle has a "working end" where the final run of rope leaves the last sheave. More mechanical advantage can be obtained if this end is attached to the moving load rather than the fixed end of the tackle.

There are various types of blocks that are used in sailing. Some blocks are used to increase mechanical advantage and others are used simply to change the direction of a line. Some blocks ratchet, which means that they turn freely when you pull a line in one direction but does not turn the other direction. This kind of block makes a line easier to hold especially on a windy day. They usually have some kind of a button or lever to turn the rachet block off turning it into a regular block that makes any lines that go into the block turn freely in both directions. Ratchet blocks are typically used on small keelboats and dinghies where the mainsheet is and jib sheets are located.

ailing terms in everyday English

; Chock a' block : Refers literally to the situation where pulling on the working line will not raise the load any further because the cheeks of one lifting block are already fast against the other. Figuratively this has come to mean that something is as full or as far as it can be.Fact|date=January 2008

ee also

* Block and tackle
* Two six heave
* Portsmouth Block Mills


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Block — may refer to: * A way of controlling train movement in railway signalling * Postage stamp block, an attached group of postage stampsObjects* A large concrete or stone brick * Block (sailing), a single or multiple pulley used on sailboats *… …   Wikipedia

  • Block Island — Infobox Settlement official name = New Shoreham, Rhode Island settlement type = Town nickname = imagesize = image caption = image mapsize = map caption = mapsize1 = map caption1 = subdivision type = Country subdivision type1 = State subdivision… …   Wikipedia

  • Block and tackle — A block and tackle [ Tackle can be pronEng|ˈteɪkəl in this usage.] is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift or pull heavy loads. TOC Overview Although used in many situations, they are… …   Wikipedia

  • Sailing stones — A sailing stone in Racetrack Playa. Sailing stones, sliding rocks, and moving rocks all refer to a geological phenomenon where rocks move in long tracks along a smooth valley floor without human or animal intervention. They have been recorded and …   Wikipedia

  • Wolfram Block — Die „Nao Victoria“, Rekonstruktion des letzten verbliebenen Schiffs der Weltumsegelung Ferdinand Magellans, Hafen von Nagoya Eine Weltumrundung bezeichnet eine Reise um die Erde. Bei einer Weltumrundung werden zu Fuß, per Fahrrad, per Auto, per …   Deutsch Wikipedia

  • Boom (sailing) — In sailing, a boom is a spar (pole), along the foot (bottom) of a fore and aft rigged sail, that greatly improves control of the angle and shape of the sail. The primary action of the boom is to keep the foot of the sail flatter when the sail… …   Wikipedia

  • Mast (sailing) — Sails on a small ship as seen from below The mast of a sailing vessel is a tall, vertical, or near vertical, spar, or arrangement of spars, which supports the sails. Large ships have several masts, with the size and configuration depending on the …   Wikipedia

  • National Sailing Centre — The National Sailing Centre is located at the south eastern tip of Singapore along the East Coast Park. It occupies 2.4 hectares of land.[1] History Opened in June 1999, the National Sailing Centre is approximately 51 minutes away from the Youth… …   Wikipedia

  • Adriaen Block — Adriaen (Aerjan) Block (c. 1567, Amsterdam ndash; buried April 27 1627, Amsterdam) was a Dutch private trader and navigator who is best known for exploring the coastal and river valley areas between present day New Jersey and Massachusetts during …   Wikipedia

  • Sheet (sailing) — This article is about the sailing term. For other uses, see Sheet. The piece of chain running diagonally up and right from the bottom left of this picture to the upper of the two yards is the fore lower topsail sheet. Some of the lines on Prince… …   Wikipedia

Share the article and excerpts

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

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.