How to Determine the Parts of a Line on a Crane

Understanding the line system of a crane is key to safe operation and accurate load handling. The “line” generally refers to the wire rope reeving through the crane’s boom, blocks, and drum. To determine the parts of the line, you need to trace how many sections of rope actually support the load.

Step 1: Identify the Load Block and Hook

1. Look at the lower block (hook block).


2. Count how many ropes (falls of line) enter the block from above.

Step 2: Trace the Rope Path

1. Follow the wire rope from the drum.


2. See how it weaves between the boom tip sheaves and the hook block.


3. Each supporting rope segment between the top and the bottom counts as one part of the line.

Step 3: Count the Supporting Parts of the Line

1. Count each segment of rope between the boom and the hook block.


2. Ignore the “dead end” (where the rope is anchored) if it does not directly support the hook.


3. Example: If the rope passes down to the hook block and back up four times, you have 8 parts of line.

Step 4: Verify with Load Chart

1. Refer to the crane’s load chart for correct reeving.


2. Match the required parts of the line to the rated load.


3. Ensure the actual reeving setup matches the chart.

Compact Example

1. A rope goes from the boom tip down to the hook block and back up 3 times.


2. That makes 6 rope segments carrying the load.


3. The crane is working with 6 parts of the line.