Deck Cranes

Rocking Test on Deck Cranes

Purpose:

The Rocking Test is a crucial inspection procedure for deck cranes to assess the structural integrity of the crane and its foundation. It helps to identify any potential weaknesses or damage that could compromise the crane’s safety and stability.

Procedure:

1. Preparation: Ensure that the crane is in a stable position and that all safety precautions are in place.
2. Manual rocking: Manually apply a rocking motion to the crane base, either by pushing or pulling on the crane structure.
3. Observation: Carefully observe the crane’s response to the rocking motion. Pay attention to any unusual sounds, vibrations, or excessive movement.
4. Inspection: Inspect the crane’s foundation, bearings, and other components for signs of damage, such as cracks, corrosion, or loose bolts.

Importance:

The Rocking Test is essential for several reasons:

• Structural integrity: It helps to identify any structural weaknesses or damage that could lead to crane failure.
• Stability: It ensures that the crane is stable and can withstand the forces generated during operation.
• Safety: A damaged or unstable crane poses a significant safety risk to both the crew and the cargo.

Slewing Bearing and Inspection

Slewing Bearing:

A slewing bearing is a large, circular bearing that allows the crane turret to rotate. It is typically located at the base of the turret and is a critical component for the crane’s operation.

Inspection:

1. Visual inspection: Inspect the slewing bearing for signs of wear, damage, or contamination.
2. Rotation test: Rotate the turret manually and listen for any unusual sounds or vibrations.
3. Grease inspection: Check the condition of the grease in the bearing. A well-lubricated bearing will operate smoothly and quietly.

Preventing Crane Turret Toppling

Several factors contribute to the stability of a crane turret, including:

• Weight distribution: Proper weight distribution within the crane helps to prevent toppling.
• Ballast: Adding ballast to the crane can improve its stability, especially when operating in rough seas.
• Crane design: The crane’s design, including the shape and size of the turret, plays a role in its stability.

Importance of Grease Inspection

Grease is essential for the proper functioning of a slewing bearing. It provides lubrication, reduces friction, and protects the bearing components from wear and damage. Regular inspection of the grease helps to ensure that the bearing is adequately lubricated and that there are no signs of contamination or deterioration.

By conducting regular Rocking Tests and inspections of the slewing bearing and its components, mariners can help to maintain the safety and reliability of deck cranes.

Load Testing of Lifting Gear

Load testing of lifting gear is a critical procedure to ensure its safety and reliability. It involves subjecting the gear to a controlled load to verify its ability to withstand the intended working load without failure. The primary objectives of load testing are:

• Verify SWL: To confirm that the gear can safely lift and handle the specified Safe Working Load (SWL).
• Identify defects: To detect any defects or weaknesses in the gear that could lead to failure.
• Ensure safety: To ensure the safety of personnel and equipment during lifting operations.

Safe Working Load (SWL)

The SWL is the maximum load that a piece of lifting gear is designed to safely lift under normal operating conditions. It is determined based on factors such as the gear’s material, dimensions, and design.

Role of Water Bags

Water bags are often used in load testing to simulate the weight of actual loads. They offer several advantages:

• Controlled weight: Water bags can be easily filled or emptied to achieve the desired weight.
• Flexibility: They can be shaped and positioned to simulate different types of loads.
• Safety: Water bags are generally safer to use than actual loads, especially when testing heavy or hazardous materials.

Pontoons for Certain Cranes

Pontoons are used for certain cranes, such as floating cranes and some offshore cranes, to provide a stable platform for the crane to operate. They offer several benefits:

• Stability: Pontoons provide a stable base for the crane, even in rough water conditions.
• Mobility: Pontoons allow the crane to be moved to different locations without requiring extensive setup or dismantling.
• Capacity: Pontoons can increase the crane’s lifting capacity by distributing the load over a larger area.

In conclusion, load testing is a vital procedure for ensuring the safety and reliability of lifting gear. The SWL is a key factor in determining the gear’s safe operating limits. Water bags are a valuable tool for simulating loads during testing, and pontoons are used to provide stability and mobility for certain types of cranes.