Pneumatic Rubber Fender Performance Under Angled Berthing: A Case Study in Energy Absorption and Service Life

A 150,000 DWT crude oil carrier approached an exposed berth in the South China Sea at a 12-degree angle. The fendering system — a set of solid rubber cone fenders — had been specified for the vessel's displacement and berthing velocity. The vessel made contact. The fender compressed, but the angular load exceeded its design limit. The fender's surface split at the shear zone, and the mounting bolts pulled through the rubber. The berthing was not unusual. The impact angle was within the terminal's operating profile. The fender was simply not designed for the combination of energy and angle that occurred.

The difference between a fender that fails under angular load and one that maintains performance at higher approach angles is not the rubber compound alone. It is the pneumatic rubber fender's use of air compressibility to absorb energy, combined with a construction that distributes stress uniformly across its surface. Selecting the correct fender for exposed berths and ship-to-shore (STS) operations is therefore not a generic specification — it determines whether the fender system survives its first major berthing event.

I. Problem Diagnosis and Technical Analysis

Failure mode. The failed cone fender showed a classic angular-load failure pattern: a diagonal surface crack extending from the mounting flange through the shear zone, with localized rubber tearing at the point of maximum hull contact. The fender's reaction force spiked, transmitting excessive load to the quay wall and the vessel's hull.

Three contributing factors emerged:

• Angular load performance: Solid rubber cone fenders have a defined compression axis. When a vessel contacts at an angle, the load vector shifts. Pneumatic fenders maintain performance at approach angles up to 15 degrees.
• Energy absorption capacity: The berthing energy calculation for the 150,000 DWT vessel at 0.12 m/s yielded approximately 1,000 kN·m. Pneumatic fenders, manufactured to ISO 17357, provide substantially greater energy absorption per unit reaction force.
• Construction integrity: Pneumatic fenders use a three-layer construction: an abrasion-resistant outer rubber, a synthetic tire-cord reinforcing layer, and an inner rubber layer for air retention.

II. Solution and Technical Justification

The replacement is a ChuncoTech pneumatic rubber fender manufactured to ISO 17357, specified as follows:

• Construction: Three layers for high tensile strength and stable shape retention.
• Angled berthing performance: Maintains rated performance at approach angles up to 15 degrees.
• Energy absorption and reaction force: Reduces hull pressure and minimizes stress on the quay wall.
• Service life and reliability: Tire-cord construction resists sunlight, ozone, heat, and oxygen.

III. Implementation and Verification

The pneumatic fenders were installed on the exposed berth following ISO 17357 guidelines. Installation included securing the fenders with chain and tire nets (Type I configuration), initial inflation to 80 kPa.

After 36 months of continuous service:

• Zero angular-load-related failures
• No surface cracking or delamination
• Measured reaction forces consistent with design values
• Fenders fully functional at approach angles up to 15 degrees

IV. Conclusion and Technical Recommendations

This case demonstrates that solid cone fenders are poorly suited to exposed berths. Engineers specifying fenders should apply these criteria:

• Require angled-performance data confirming rated energy absorption.
• Specify ISO 17357 compliance.
• Select tire-cord-reinforced construction.
• Consider chain and tire-net protection (Type I configuration).

Wuxi ChuncoTech Rubber provides pneumatic rubber fenders manufactured to ISO 17357. For detailed specifications, model sizes, or a custom fender discussion, visit our pneumatic rubber fender product page: https://www.chuncotechrubber.com/pneumatic-rubber-fender-product/.