Thursday, January 12, 2012

How are block and tackle used in boats?

what advantage do they give



what are they actually used for



please help with any information you know about the subject in general!!!How are block and tackle used in boats?
As mentioned before, mechanical advantage in pulling a line. Put more simply, blocks reduce the effort needed to pull a line regardless of that lines use. Each loop in a line...with blocks at each loop doubles the power of your pull.



A Block in particular, is a wood, metal or composite case which encases one or more sheives(the round wheel) for lines.



Block is singular.

Tackle is more than one block.

Tackle can be rigged either to advantage or dissadvantage.



A big name in boats for blocks is Harken. www.harken.comHow are block and tackle used in boats?
Block %26amp; tackle are use between 2 areas to increase the pulling pressue between them%26gt; Like a down haul on the mast to the boom%26gt; Or on the traveler on the boom%26gt;For control on a reach with the boom out over the side of the sail boat%26gt;%26gt;And the is only 1 rope on a boat it hanges from the bell%26gt;How are block and tackle used in boats?
good Mechanical engineers all.....not a sailor amonst them, however.



on a boat you use tackle for all kinds of things.



the outhaul of the main is a single block that pulls the bottom (foot) of the mainsail tight.



the vang is a 2-3 or 4 block tackle that pulls down on the main boom.



the vang is attached to the boom at one end and the Traveler at the other. The traveler is used to move the boom left and right WRT the boat centerline it may have 2 or 4 blocks depending on the size of the boom.



lastly you can use the boom while in port for lifting cargo on or off the boat. you would use tackle for that too.



wer
B+T (or 'purchase') are used to give mechanical advantage - in other words to make your pull more powerful. The word advantage carries a technical meaning in this context - the number of times the rope goes around the block and tackle, coupled with the direction that you pull tells you how many times you multiply your pull . There is no free lunch - the more the mechanical advantage (number of times the rope goes around) the slower your pull affects what you are pulling and the more friction there is to pull against. Used in many contexts on board a ship, usually to apply tension to something that needs to be really tight. Like the rope that pulls a sail up the mast (halyard). And of course many more examples....

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