I don't know IF that's clear? I attempted to--& did--run rope thru 2 blocks of 3 pulleys each to make a hoist. While it 'worked' it seemed to have some crossed lines. Especially confusing (to me) is the one connecting lower tie-point on one of the block units??? Where does one start? This must seem jumbled... Probably cuz i'm confused :-( Roger...over...
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Try this....
Start by having your "fixed point" eye connection on the top block, then its just a matter of: down to and around pulley #1 on lower block up to and around pulley #1 on upper block down to and around pulley #2 on lower block up to and around pulley #2 on upper block down to and around pulley #3 on lower block up to and around pulley #3 on upper block Be sure to thread them thru all the same way: Go through the back and out the front of the lower block pulley #1 then up and thru the front and out the back on the upper block in pulley #1, then down to the back of the lower block on pulley #2 and so on.........When your done the bitter end coming off the front side of the top block on pulley #3 will be your hoisting line. Hope thats not too confusing, I can see it in my mind , but getting it to words is difficult. Jeff
Start by having your "fixed point" eye connection on the top block, then its just a matter of: down to and around pulley #1 on lower block up to and around pulley #1 on upper block down to and around pulley #2 on lower block up to and around pulley #2 on upper block down to and around pulley #3 on lower block up to and around pulley #3 on upper block Be sure to thread them thru all the same way: Go through the back and out the front of the lower block pulley #1 then up and thru the front and out the back on the upper block in pulley #1, then down to the back of the lower block on pulley #2 and so on.........When your done the bitter end coming off the front side of the top block on pulley #3 will be your hoisting line. Hope thats not too confusing, I can see it in my mind , but getting it to words is difficult. Jeff
general rules for gun tackels
So you want to be salty a A tackle is the use of only one block to turn the line so as to make it more useful in lifting. Course the same thing used for something other than lifting is called a turning block. A gun tackle is when you use two blocks (top and bottom) and a luft tackle is when you use three blocks (top middle and bottom) As a general rule you want the working end of the line attached to either the top or bottom line and then immediately go to the outside sheve on the other block followed by the outside sheve on the block you started with. Then it is just a mater of lacing your shoes to keep thing in order. If you care which end is up because of an attachment on one block then I find it better to put the blocks in place or so that they are in the correct relationship that you want and then reave the line. A luft tackle is a combination of a plane tackle and a gun tackle. They are quite handy when lifting to great heights as you don't need enormous amounts of line. To construct attach the line to the load then up and over the single block and back down to the top block attachment point of a gun tackle. The gun tackle does the work and the tackle gets the line to where the load is and in the right direction. All tackles are measured in purchase. If you count the number of lines going between the top and bottom blocks that is your purchase. Paraphrased from "The Young Sea Officer's Sheet Anchor or a key to the leading of rigging and to practical seamanship" by Darcy Lever
So you want to be salty a A tackle is the use of only one block to turn the line so as to make it more useful in lifting. Course the same thing used for something other than lifting is called a turning block. A gun tackle is when you use two blocks (top and bottom) and a luft tackle is when you use three blocks (top middle and bottom) As a general rule you want the working end of the line attached to either the top or bottom line and then immediately go to the outside sheve on the other block followed by the outside sheve on the block you started with. Then it is just a mater of lacing your shoes to keep thing in order. If you care which end is up because of an attachment on one block then I find it better to put the blocks in place or so that they are in the correct relationship that you want and then reave the line. A luft tackle is a combination of a plane tackle and a gun tackle. They are quite handy when lifting to great heights as you don't need enormous amounts of line. To construct attach the line to the load then up and over the single block and back down to the top block attachment point of a gun tackle. The gun tackle does the work and the tackle gets the line to where the load is and in the right direction. All tackles are measured in purchase. If you count the number of lines going between the top and bottom blocks that is your purchase. Paraphrased from "The Young Sea Officer's Sheet Anchor or a key to the leading of rigging and to practical seamanship" by Darcy Lever
Thanks guys...
...but, is the "fixed point" below the row of 'blocks' on one of the set of 3 pulleys? IF so, i tie to that point (top block)then down to lower # 1, then up to # 1, then back down to # 2 etc..etc??? I dun-no, peppering me with all dat salty stuff...i's goin'hafta thingk about... Roger
...but, is the "fixed point" below the row of 'blocks' on one of the set of 3 pulleys? IF so, i tie to that point (top block)then down to lower # 1, then up to # 1, then back down to # 2 etc..etc??? I dun-no, peppering me with all dat salty stuff...i's goin'hafta thingk about... Roger
I think you have it
There is a "little roller" or round hole on the outside of the block on the end opposite the place that it attaches to whatever will take the load. This is (sorry the terms just make talking about it easier) called a becket. You can get blocks with and without beckets. For a gun tackle you need one of the blocks to have a becket. It does not matter which one. Just cause I'm nosy, what are you going to use your tackle for? block wo/becket http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/47966/377%20710%201752/0/Blocks/Primary%20Search/mode%20matchallpartial/0/0?N=377%20710%201752&Ne=0&Ntt=Blocks&Ntx=mode%20matchallpartial&page=CategoryDisplayLevel1&isLTokenURL=true&storeNum=null&subdeptNum=null&classNum=null block with becket http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/120017/377%20710%201752/0/Blocks/Primary%20Search/mode%20matchallpartial/30/0?N=377%20710%201752&Ne=0&Ntt=Blocks&Ntx=mode%20matchallpartial&page=CategoryDisplayLevel1&isLTokenURL=true&storeNum=null&subdeptNum=null&classNum=null fiddle block with becket http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/119894/377%20710%201752/0/Blocks/Primary%20Search/mode%20matchallpartial/10/0?N=377%20710%201752&Ne=0&Ntt=Blocks&Ntx=mode%20matchallpartial&page=CategoryDisplayLevel1&isLTokenURL=true&storeNum=null&subdeptNum=null&classNum=null
There is a "little roller" or round hole on the outside of the block on the end opposite the place that it attaches to whatever will take the load. This is (sorry the terms just make talking about it easier) called a becket. You can get blocks with and without beckets. For a gun tackle you need one of the blocks to have a becket. It does not matter which one. Just cause I'm nosy, what are you going to use your tackle for? block wo/becket http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/47966/377%20710%201752/0/Blocks/Primary%20Search/mode%20matchallpartial/0/0?N=377%20710%201752&Ne=0&Ntt=Blocks&Ntx=mode%20matchallpartial&page=CategoryDisplayLevel1&isLTokenURL=true&storeNum=null&subdeptNum=null&classNum=null block with becket http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/120017/377%20710%201752/0/Blocks/Primary%20Search/mode%20matchallpartial/30/0?N=377%20710%201752&Ne=0&Ntt=Blocks&Ntx=mode%20matchallpartial&page=CategoryDisplayLevel1&isLTokenURL=true&storeNum=null&subdeptNum=null&classNum=null fiddle block with becket http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/119894/377%20710%201752/0/Blocks/Primary%20Search/mode%20matchallpartial/10/0?N=377%20710%201752&Ne=0&Ntt=Blocks&Ntx=mode%20matchallpartial&page=CategoryDisplayLevel1&isLTokenURL=true&storeNum=null&subdeptNum=null&classNum=null
Three-fold purchase
Roger, For purposes of illustration, let's consider the upper block the one with the becket. The becket is the eye on the bottom of the block. It is necessary to lay one of the three sheaved blocks on it's side with the other laying 90 degrees opposed, or on it's sheaves. The difficulty in reaving this tackle is that, if you do not get it right, the top block will capsize itself and you'll not get a straight pull. Attach the bitter end to the becket. Reeve the line through the center sheave of your lower, or floating, block. Then back up to the stationary block to one of the outside sheaves and come back down to an outside sheave. You will then go up and through the other outside sheave, through the remaining sheave on the floating block, and finally through the center sheave of your stationary block. The two blocks will end up 90 degrees opposed to each other as they hang. This is a rare purchase for line, but not uncommon in wire rope. With line you end up with the full 10% friction loss per block. So, on a six-to-one purchase you will lose 60% of your mechanical advantage to friction. Wire rope and the blocks used for the same is not as inefficient in this purchase.
Roger, For purposes of illustration, let's consider the upper block the one with the becket. The becket is the eye on the bottom of the block. It is necessary to lay one of the three sheaved blocks on it's side with the other laying 90 degrees opposed, or on it's sheaves. The difficulty in reaving this tackle is that, if you do not get it right, the top block will capsize itself and you'll not get a straight pull. Attach the bitter end to the becket. Reeve the line through the center sheave of your lower, or floating, block. Then back up to the stationary block to one of the outside sheaves and come back down to an outside sheave. You will then go up and through the other outside sheave, through the remaining sheave on the floating block, and finally through the center sheave of your stationary block. The two blocks will end up 90 degrees opposed to each other as they hang. This is a rare purchase for line, but not uncommon in wire rope. With line you end up with the full 10% friction loss per block. So, on a six-to-one purchase you will lose 60% of your mechanical advantage to friction. Wire rope and the blocks used for the same is not as inefficient in this purchase.
More thanks...
...for the sites, but not the style i'm concerned with. I think Jeff gets my problem and has remedied it I was going to use it in a mast lowering/raising rig. Had it working, but too much nusiance to go under only one bridge out of 50+ that i go under with my cut-off mast... Roger
...for the sites, but not the style i'm concerned with. I think Jeff gets my problem and has remedied it
I was going to use it in a mast lowering/raising rig. Had it working, but too much nusiance to go under only one bridge out of 50+ that i go under with my cut-off mast... Roger
Blocks wind up at 90 degrees to each other
Funny you should ask this question, as I was just wrestling with it today. Guy explains it well & here's a link to a site I found through a Google search, with an illustration as well. My PO added 2 triple blocks to aid in hauling up the centerboard, however he had way too much line that was not helping the cockpit spaghetti, so I replaced it with a shorter line. Being an idiot, I didn't look carefully at how it was reeved first. I reeved the way Jeff suggested, but the lines kept moving to the edge of the sheeves, plus the entire arrangement kept yawing because the line started on one outer sheeve & came out off the other side. I don't recall the blocks being at 90˚ to each other, but that appears to be the correct reeving.
Funny you should ask this question, as I was just wrestling with it today. Guy explains it well & here's a link to a site I found through a Google search, with an illustration as well. My PO added 2 triple blocks to aid in hauling up the centerboard, however he had way too much line that was not helping the cockpit spaghetti, so I replaced it with a shorter line. Being an idiot, I didn't look carefully at how it was reeved first. I reeved the way Jeff suggested, but the lines kept moving to the edge of the sheeves, plus the entire arrangement kept yawing because the line started on one outer sheeve & came out off the other side. I don't recall the blocks being at 90˚ to each other, but that appears to be the correct reeving.
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