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Ever wondered how ships dock safely without damage? Pneumatic fenders play a vital role in protecting vessels. Choosing the right pneumatic fender size is crucial for safe berthing.
Pneumatic fender size defines the fender’s diameter and length when inflated. It impacts energy absorption and hull protection during docking.
In this post, you’ll learn how to read the pneumatic fender size chart and select the right size for your vessel or berth.
Table of Contents
Pneumatic fenders come in a range of standard sizes defined by ISO 17357-1:2014. These sizes specify the diameter and length measured in millimeters when the fender is inflated to the rated initial inflation pressure (IIP). The smallest standard size is 500×1000 mm, while the largest reaches 4500×12000 mm. This range covers most commercial and offshore applications.
Standard sizes are expressed as Diameter × Length (D×L). For example, a 3300×6500 mm fender is 3.3 meters in diameter and 6.5 meters long at 50 kPa IIP. These sizes ensure compatibility across various vessel types and berthing scenarios. Manufacturers also offer intermediate sizes between the standard designations to meet specific needs.
Two key performance metrics define fender effectiveness:
Guaranteed Energy Absorption (GEA): The minimum energy a fender absorbs at 60% compression, measured in kilojoules (kJ). This value guarantees the fender’s capacity to safely absorb berthing energy without damage.
Reaction Force (RF): The force the fender exerts on the vessel hull at 60% deflection, measured in kilonewtons (kN). It indicates the pressure applied to the hull. ISO 17357-1:2014 allows a ±10% tolerance on RF values.
Both GEA and RF are rated at 50 kPa initial inflation pressure. Increasing IIP to 80 kPa can raise these values by about 30–40%, useful when space is limited or energy absorption needs are higher.
Common sizes for specialized operations include:
LNG Terminals: Larger fenders like 3300×6500 mm and 4500×9000 mm are popular. They provide high energy absorption (1,814 to 4,752 kJ) needed for large LNG carriers.
Ship-to-Ship Transfer (STS): Sizes such as 2500×5500 mm and 3300×6500 mm are typical, balancing energy absorption and reaction force for vessels between 30,000 and 80,000 DWT.
These sizes help protect sensitive hull structures and ensure safe, efficient berthing.
Hull pressure is the internal air pressure inside the fender at 60% deflection. It directly translates to the pressure applied on the vessel hull contact area. Maintaining hull pressure within vessel limits is critical to prevent structural damage.
Two IIP ratings exist:
50 kPa (Standard): Most common, balancing energy absorption and hull pressure.
80 kPa (High Pressure): Offers 15–20% more energy absorption but increases hull pressure. Used when berth space is tight or berthing energy is high.
Choosing the right IIP depends on vessel specifications, berth geometry, and safety margins.
Understanding the pneumatic fender size chart is essential for selecting the right fender for your vessel or berth. The chart provides detailed performance data based on standard testing conditions. Here’s how to interpret the main elements:
Each fender size is shown as Diameter × Length (D×L) in millimeters. This refers to the outer diameter and overall length when inflated to the rated initial inflation pressure (IIP). For example, a 3300×6500 mm fender means:
Diameter: 3.3 meters
Length: 6.5 meters
This measurement is taken at the standard 50 kPa IIP unless otherwise noted.
Performance data in the chart is rated at 60% deflection. This means the fender is compressed to 40% of its original diameter during testing. This level is the standard performance point, not the maximum compression limit. Exceeding 60% risks permanent damage to the fender.
At 60% deflection, the chart lists two critical values:
Guaranteed Energy Absorption (GEA): The minimum energy the fender must absorb, measured in kilojoules (kJ). This guarantees the fender’s ability to safely absorb impact energy during berthing.
Reaction Force (RF): The force the fender applies to the vessel hull, measured in kilonewtons (kN). This force reflects the pressure the hull experiences when the fender compresses.
GEA has no lower tolerance — the fender must at least meet the stated value.
RF has a ±10% tolerance as allowed by ISO 17357-1:2014. This means actual reaction force can be 10% higher or lower than the rated value.
Both values are crucial. A fender absorbing enough energy but exerting excessive reaction force may damage the vessel’s hull. Always compare RF against the hull pressure limit.
Hull pressure represents the internal air pressure inside the fender at 60% deflection. It equals the pressure applied to the vessel’s hull contact area. Maintaining hull pressure below the vessel’s structural limit is vital to avoid damage.
The contact area depends on the fender’s diameter and length. Larger contact areas reduce hull pressure for the same reaction force. Thus, checking RF divided by contact area against hull pressure limits is a key step.
Two initial inflation pressures (IIP) are common:
50 kPa (Standard): Most pneumatic fenders are rated at this pressure. It balances energy absorption and hull pressure for typical applications.
80 kPa (High Pressure): Used when berth space is limited or berthing energy is high. At 80 kPa, GEA and RF increase by roughly 30–40%. This means more energy absorption but also higher hull pressure.
Selecting between 50 kPa and 80 kPa depends on berth geometry, vessel requirements, and safety margins.
Choosing the correct pneumatic fender size involves several important factors. The goal is to ensure the fender can absorb the berthing energy safely while protecting the vessel’s hull from excessive pressure.
The first step is to calculate the Effective Kinetic Energy (EKE) the fender must absorb during berthing. This energy depends on:
Vessel displacement (weight)
Berthing velocity squared
Correction factors for eccentricity, berth configuration, softness, and added mass
The formula is based on PIANC MarCom Report No. 211 (2024). It adjusts the basic kinetic energy to reflect real berthing conditions. EKE represents the minimum energy the fender must safely absorb.
Different vessel types have varying hull pressure tolerances. For example:
LNG carriers typically allow hull pressures around 200–250 kN/m²
Bulk carriers and tankers often tolerate higher pressures
The fender’s reaction force (RF) divided by its contact area must stay below the vessel’s hull pressure limit. Exceeding this risks structural damage.
Berthing velocity varies by vessel size and berth exposure:
Sheltered berths with tug assistance might use 0.10 m/s
Exposed offshore mooring points (SPM) may see 0.25–0.30 m/s
Higher approach velocities increase EKE, requiring larger or higher-pressure fenders. Exposure class affects safety margins in size selection.
Consider an 80,000 DWT tanker approaching at 0.15 m/s with correction coefficients:
Cm = 1.8 (mass correction)
Ce = 0.5 (eccentricity)
Cc = 1.0 (configuration)
Cs = 1.0 (softness)
Calculating EKE yields roughly 350 kJ. Applying a safety factor of 1.5 gives a required GEA of at least 525 kJ. From the standard size chart, a 2500×5500 mm fender with 943 kJ GEA at 50 kPa inflation provides ample margin. A smaller 2500×4000 mm fender (663 kJ) might also work but offers less contact length.
Selecting a fender size from the energy absorption perspective alone is not enough. Always check that the fender’s reaction force divided by contact area does not exceed the vessel’s hull pressure limit. This step avoids hull damage during berthing impacts.
Pneumatic fenders come in various sizes tailored to specific berthing and mooring needs. Knowing typical sizes by application helps in initial planning and budgeting. Here’s a breakdown of common applications and their recommended pneumatic fender sizes:
Harbour Berthing: For smaller vessels up to 5,000 DWT, fenders around 1000×2000 mm are typical. These provide enough energy absorption for low-energy berthing scenarios such as small cargo ships or fishing vessels.
Port Quay Berthing: Medium-sized vessels between 5,000 and 30,000 DWT usually require fenders sized 1500×3000 mm to 2000×3500 mm. These sizes absorb moderate energy and offer balanced reaction forces suited for standard port operations.
STS operations involve vessels typically between 30,000 and 80,000 DWT. The fenders used here must handle higher berthing energies while controlling hull pressure. Common sizes include:
2500×5500 mm
3300×6500 mm
These sizes offer Guaranteed Energy Absorption (GEA) from about 943 to 1,814 kJ, providing ample protection during transfers. The OCIMF STS Transfer Guide references these sizes as industry standards.
LNG carriers and Floating Storage Regasification Units (FSRUs) are large vessels requiring high-capacity fenders. Recommended sizes include:
3300×6500 mm
4500×9000 mm
These fenders provide very high GEA, ranging from 1,814 kJ up to 4,752 kJ. They protect sensitive hull structures and membrane tanks from impact damage during berthing at terminals.
SPM and offshore mooring systems handle tankers, Floating Storage and Offloading units (FSOs), and other large vessels. Typical fender sizes here are:
2500×4000 mm
3300×4500 mm
These sizes balance energy absorption and reaction force for high-energy offshore impacts, where wave and current forces add complexity.
For temporary uses such as drydock or shipyard operations, fender sizes vary widely depending on vessel class. Common sizes include:
1000×2000 mm for small vessels
Up to 2500×5500 mm for larger vessels
These fenders provide adequate protection during short-term berthing or vessel movement in controlled environments.
Application | Typical Vessel Class | Recommended Size (D×L mm) | GEA Range (kJ) | Notes |
|---|---|---|---|---|
Harbour berthing | Up to 5,000 DWT | 1000×2000 | 45 | Low-energy berthing |
Port quay berthing | 5,000–30,000 DWT | 1500×3000 to 2000×3500 | 153–308 | Standard port operations |
Ship-to-ship transfer (STS) | 30,000–80,000 DWT | 2500×5500 to 3300×6500 | 943–1,814 | OCIMF STS Transfer Guide |
LNG carrier / FSRU berthing | 80,000–180,000 m³ | 3300×6500 to 4500×9000 | 1,814–4,752 | SIGTTO / PIANC 211 references |
SPM / offshore mooring | Tankers, FSOs | 2500×4000 to 3300×4500 | 663–1,175 | High-energy offshore impact |
Drydock / shipyard | All vessel types | 1000×2000 to 2500×5500 | 45–943 | Temporary deployment |
These sizes serve as starting points. Final selection requires detailed berthing energy calculations and hull pressure checks per vessel and berth specifics.
ISO 17357-1:2014 Clause 6.3.3 allows custom pneumatic fender sizes beyond the 14 standard dimensions. These custom sizes must meet the same performance criteria as standard fenders, including Guaranteed Energy Absorption (GEA), Reaction Force (RF), and deflection behavior. Verification happens through prototype testing under Clause 8, ensuring safety and reliability.
The standard recognizes that some projects need fenders with non-standard diameters or lengths. Custom sizes can vary in diameter, length, or both, as long as they fulfill the standard’s performance requirements. This flexibility helps accommodate unique berth configurations, vessel types, or operational constraints.
Custom sizes often arise due to:
FSRU retrofit projects: Berth geometry may limit maximum diameter, requiring longer fenders or altered proportions.
SPM terminals: Non-standard vessel approach angles or mooring setups may need tailored fender dimensions.
Unique diameter-to-length ratios: Some applications call for ratios outside the standard series to optimize energy absorption or fit space constraints.
Special vessel classes: Vessels with unusual hull shapes or sensitive structures may require customized fender sizing.
When ordering custom fenders, buyers must specify:
Diameter and length in millimeters
Required Guaranteed Energy Absorption (GEA) in kilojoules
Maximum allowable Reaction Force (RF) in kilonewtons
Initial inflation pressure (either 50 kPa or 80 kPa)
Fender construction type (Type I or Type II, as per ISO classification)
Providing detailed vessel and berth data helps manufacturers design the right fender to meet operational needs.
Custom sizes require prototype testing to verify compliance with ISO 17357-1:2014 Clause 8. This process includes:
Compression testing at 60% deflection
Measurement of GEA, RF, and hull pressure
Documentation of performance curves and tolerances
Testing adds lead time, typically extending delivery to 8–14 weeks compared to 4–6 weeks for standard sizes. Early planning and communication with manufacturers reduce delays.
Reputable manufacturers provide engineering support during custom fender specification. This includes:
Reviewing vessel dimensions and berthing conditions
Recommending optimal size and inflation pressure
Confirming performance targets and safety margins
Coordinating prototype testing and certification
This collaborative approach ensures the custom fender fits the project requirements and complies with ISO standards.
Standard pneumatic fenders under ISO 17357-1:2014 range from 500×1000 mm up to 4500×12000 mm in diameter × length. These sizes cover most commercial port and offshore uses. The common sizes for everyday applications fall between 1500×3000 mm and 4500×9000 mm. If your project requires a size outside this range, custom sizes are allowed under Clause 6.3.3, but they must meet the same strict performance standards.
For ship-to-ship (STS) operations, which usually involve vessels between 30,000 and 80,000 DWT, fenders sized 2500×5500 mm to 3300×6500 mm are common. These sizes provide guaranteed energy absorption (GEA) between 943 and 1,814 kJ at 60% compression. Larger vessels, above 80,000 DWT, often require bigger fenders like 3300×6500 mm or 4500×9000 mm. The final size depends on factors such as berthing velocity and vessel displacement.
GEA stands for Guaranteed Energy Absorption. It is the minimum energy the fender must absorb at 60% deflection, measured in kilojoules (kJ). RF means Reaction Force, which is the force the fender applies on the vessel hull at the same deflection, measured in kilonewtons (kN). Both values are tested at 50 kPa initial inflation pressure following ISO 17357-1:2014 standards. GEA ensures the fender can safely absorb impact energy, while RF indicates the pressure exerted on the hull.
Yes. The ISO standard allows custom sizes outside the 14 standard dimensions. These custom fenders must meet the same performance criteria as standard ones, verified through prototype testing. Custom sizes are common in projects like FSRU retrofits, SPM terminals, or where berth geometry limits standard sizes. When ordering, you must specify diameter, length, GEA, maximum RF, inflation pressure, and construction type.
Start by calculating the Effective Kinetic Energy (EKE) the fender must absorb based on vessel weight, berthing velocity, and correction factors. Then, check the vessel’s hull pressure limit. The fender’s reaction force divided by the contact area must stay below this limit to avoid damage. Consider approach velocity and exposure class for safety margins. Finally, select a size from the chart that meets or exceeds the required GEA and keeps hull pressure safe. Always consult manufacturers for engineering support and verification.
Understanding pneumatic fender size is crucial for safe and efficient vessel berthing. The size chart and performance data offer essential guidance on energy absorption and reaction force. Selecting the correct fender size protects vessel hulls from damage while meeting operational needs. For unique requirements, consulting manufacturers ensures proper customization and compliance. www.hongruntongfender.com Hongruntong Marine (Beijing) Co., Ltd. provides high-quality pneumatic fenders designed to deliver reliable protection and tailored solutions for diverse marine applications.
A: Pneumatic fender size refers to the diameter and length of the fender when inflated, critical for ensuring proper energy absorption and hull protection during berthing.
A: The chart shows sizes as Diameter × Length in millimeters, with performance data like Guaranteed Energy Absorption (GEA) and Reaction Force (RF) at 60% compression.
A: Larger pneumatic fender sizes provide higher energy absorption needed for big LNG carriers, while smaller sizes suit low-energy berthing of small vessels.
A: Yes, the fender’s reaction force divided by contact area must stay below the vessel’s hull pressure limit to avoid damage.
A: Yes, custom sizes beyond standard ranges can be made but must meet ISO performance standards through prototype testing.
