1. Using the Boom Angle Indicator
Lifting With Your SPYDERCRANE
KBT 5.5
Welcome to Lesson Topic 5.5, Using the Boom Angle Indicator

2. Topic Overview and Contents
This Lesson Topic (Using the Boom Angle Indicator) is designed to provide you with an understanding of how to use the BOOM ANGLE INDICATOR of your SPYDERCRANE.
You will learn about:
How to use the Boom Angle Indicator to determine the boom’s angle
How to use the Boom Angle Indicator (along with knowing the Boom Stage) to determine the WORKING RADIUS of the SPYDERCRANE
It is YOUR RESPONSIBILITY to read and understand the user manuals included with your SPYDERCRANE and the warning decals posted on it
This Segment Topic covers ALL SPYDERCRANEs, but the images depict the 095-/200-Series SPYDERCRANE
This lesson topic goes over how to use the Boom Angle Indicator installed on all SPYDERCRANEs.

3. Learning Objective(s)
The learning objective for this Lesson Topic is for each student to…
DLO 5.5.1: Identify the function and purpose of the BOOM ANGLE INDICATOR.
DLO 5.5.2: Identify the two chart elements of the BOOM ANGLE CHART.
DLO 5.5.3: Explain how to identify the BOOM STAGE, BOOM ANGLE, and WORKING RADIUS.
DLO 5.5.4: Explain what to do if the BOOM ANGLE INDICATOR is laying in-between two WORKING RADIUS CELLS.
You need to know three pieces of information to determine how much your SPYDERCRANE can safely lift. In the previous Lesson Topic, you learned how to read your SPYDERCRANE’s boom for its Boom Stage. In this lesson topic, you will learn how to use the Boom Angle Indicator to figure out, among other things, your SPYDERCRANE’s Working Radius.

4. The Boom Angle Indicator and Chart
The Boom Angle Indicator (and Chart) is an Operator Aid posted on Boom Section One
Boom Angle Chart identifies Boom Stages, Boom Angles, and available Working Radii
Boom Angle Indicator points toward the SPYDERCRANE’s boom angle
    Your SPYDERCRANE is equipped with BOOM ANGLE INDICATORS installed on both sides of Boom Section One. The Boom Angle Indicator is manual operator's aid composed of a gravity needle and a chart that the needle intersects.
    The FUNCTIONS of the Boom Angle Indicator are to help you to figure out the BOOM ANGLE and the WORKING RADIUS of your SPYDERCRANE's boom.
    Ultimately, the PURPOSE of the Boom Angle Indicator is to identify the SPYDERCRANE's Working Radius, so that you can figure out the Rated Load Capacity of your SPYDERCRANE.
    The Boom Angle Indicator has two parts: the actual indicator that is needle suspended from a swivel that is always pointing down (90° to the horizon) and the BOOM ANGLE CHART which is the decal that is applied to the boom. 

5. Breaking Down the Boom Angle Chart​
     When you command a BOOM UP, or DOWN, the Boom Angle Indicator rotates on its swivel so that it is always pointing down. The chart of the Boom Angle Chart is fixed to the boom and rotates with it. The chart is divided into TWO ELEMENTS:
The BOOM ANGLE COLUMNS that start at the bottom of the chart.  This row lists all of the available boom angles (in 10° increments). The angle of the boom is the Boom Angle Cell that the indicator is pointing at.
The BOOM STAGE ROWS are the four, or five rows above the boom angle row. Each row corresponds to a Boom Stage. The numbers within the individual row cells are the Working Radius Values that correspond to a specific Boom Stage and Boom Angle.   
    To use the chart, you simply follow the Boom Angle Column (by following the indicator UP) until it intersects the Boom Stage Row of the boom stage your SPYDERCRANE's boom is in, the number in the cell at the intersection is your SPYDERCRANE's Working Radius.  

6. The Slew Center
    The Boom Turret of your SPYDERCRANE sits on a TURNTABLE, which allows you to SLEW the boom clockwise and counter-clockwise. The center of this rotation is called the SLEW CENTER.  
    Imagine the Slew Center as a vertical line that runs through the center of the Turntable. 

7. The Slew Center and Hook Center
    The Boom Turret of your SPYDERCRANE sits on a TURNTABLE, which allows you to SLEW the boom clockwise and counter-clockwise. The center of this rotation is called the SLEW CENTER.  
    Imagine the Slew Center as a vertical line that runs through the center of the Turntable. 
   
The HOOK CENTER is the center-of-gravity when it is hanging freely at the end of the SPYDERCRANE's boom. If you properly rig the load when attaching it the hook, the Hook Center should also run through the load's center-of-gravity.
    Like the Slew Center, imagine a vertical line running through the center of the hook. 

8. The Working Radius
    Working Radius is the HORIZONTAL distance between the two centers. It is important to remember that this distance is always horizontal, it DOES NOT matter if the hook is above, or below, the SPYDERCRANE. 
    Technically, the distance between the Slew Center and Hook Center is a the working range, but, since your SPYDERCRANE's boom slews 360°, it becomes the Working Radius. 

9. Working Radius and Rated Load Capacity​
    All things being equal, your SPYDERCRANE's Working Radius is the biggest factor in determining its Rated Load Capacity. 
    Generally, the GREATER your SPYDERCRANE's Working Radius the LOWER its Rated Load Capacity. 

10. Using the Boom Angle Indicator and Chart1
Identify the Boom Stage
Identify the Boom Angle
Identify the Working Radius 3
    To use the Boom Angle Indicator: 
Look at where the gravity needle is pointing to along the Boom Angle Row; in this image, the needle is pointing to 30°.  
Follow the gravity needle UP until you get to the Boom Stage Row that corresponds to your SPYDERCRANE's boom stage. The number in the individual cell that is at the intersection of the gravity needle and the Boom Stage Row is your SPYDERCRANE's working radius. 
    In these images you can see: 
The boom is in Stage 3.
The boom angle is 30°.
The working radius is 15 feet. 2