In quay-wall design and maintenance, the smoothened front face that receives berthing contact and protects the wall is termed the fending system. Which materials are commonly used to construct fenders?

Introduction / Context:
Fenders protect quay walls and vessels by absorbing and distributing berthing energy. Historically and in modern practice, a variety of materials are used to create a durable, low-friction contact surface and energy-dissipating system.

Given Data / Assumptions:

• The question focuses on the protective contact surface (fending) of quay walls.
• Materials should withstand marine exposure and berthing impact.
• Traditional and modern materials are both acceptable answers.

Concept / Approach:
Granite rubbing courses resist abrasion; timber fenders provide resilience and are easy to replace; steel elements (sometimes combined with rubber/foam units) distribute loads and protect the wall face. Modern systems often use rubber or composite panels mounted on steel frames, but stone and timber remain common in legacy structures.

Step-by-Step Solution:
Identify typical historic material: granite stone on the contact face.Recognize timber as a sacrificial, resilient fending element.Acknowledge steel as a common framing/contact material in modern fender panels.Hence, “All the above” is correct.

Verification / Alternative check:
Port engineering catalogs show timber piles, steel rub rails, and granite courses across different installations.

Why Other Options Are Wrong:

• Limiting to only two materials ignores widely used alternatives across eras and designs.

Common Pitfalls:
Confusing the fender surface (contact/rubbing face) with the energy-absorbing unit (often rubber); assuming one material suits all exposure conditions.

Final Answer:
All the above.