This adds a little bit of speed back to the crane and reduces the weight of the rope. you get a difference of two parts of line. You would round this up to 7 or 8 parts of line depending on if you want even or odd parts of line.Īs you can see if you were to use the capacity of 200,000 lbs. Now if we stay with the previous example and use a line pull capacity of 20,000 lbs. of load to lift, a crane block that weighed 20,000 lbs. This maximum load includes the weight of the lift, the crane block, all rigging, and anything else that would be lifted by the crane rope. The second approach to determining the number of lines required is to determine your maximum load below the boom or jib tip. So if your crane capacity is 200,000 lbs. Each crane has a specified wire rope diameter that is to be used on it and therefore a specified rope capacity. You will then determine how many parts of line you need based on that capacity. The first approach to determining the number of lines required is to determine the maximum crane capacity that will be used on the crane you have configured. In the past having an odd number parts of line has cause the crane block to tilt a bit versus having and even number of lines. Another issue to discuss is whether you have an even or odd number of parts of line. The more parts of line installed, the slower the block will move up and down. The number of parts also affects the speed in which the crane block can be raised up and down.
Therefore having an excess number of line parts reduces the amount of capacity you have. Secondly, on most cranes, the weight of the lines needs to be deducted from the capacity of the crane. First and foremost you need to the proper number of lines to have the enough capacity to make the lift. Let’s first discuss why the number of parts of line is important. These two approaches can lead to very different answers. There are two main ways to determine how many parts of rope or line you may need installed on your crane to make a lift properly and safely.įirst you need to decide whether you want to base your number of parts on the capacity of the crane in its configuration or based on the load you will be lifting.