Flange Structure Analysis of Pneumatic Rubber Fenders
Why Flange Structure Is More Than Just a Detail
When it comes to marine fenders, most people focus on the body of the fender — the rubber, the air pressure, and the size. But in reality, the small components matter just as much. One of those components is the flange structure at the end of the pneumatic rubber fenders.
Imagine a ship docking during rough sea conditions. The fender must absorb immense force and protect the hull. If the flange — the connection point at the end of the fender — fails, the entire protective system collapses. This is why understanding the flange structure isn’t just about technical specs. It’s about reliability, cost, safety, and customer trust.
Main Flange Types in Pneumatic Rubber Fenders
There are two main flange connection types at the end of a pneumatic fender: the Ball Type Flange and the Cage Type Flange.
1. Ball Type Flange
In the Ball Type Flange, the inner flange is embedded inside the body of the fender. It’s fixed directly to the rubber body and works with an external flange that’s bolted in place. The protective tire-net — made of chain and rubber — is not directly connected to the flange system.
Main components include:
Rotating ring
Inner flange
Outer flange
Nuts and bolts
Chains
Shackles
This design is known for its simplicity and cost-efficiency in manufacturing.
2. Cage Type Flange
In the Cage Type Flange, the outer flange connects directly to the end of the tire-chain mesh. The fender body no longer bears the load directly. Instead, the load is distributed through the cage-like net structure, which is secured onto the outer flange.
This design essentially lets the cage absorb mechanical strain, leaving the fender body protected even if something goes wrong.
Even if the chain breaks or the flange is damaged, the body remains intact.
Comparing the Two Designs
At first glance, the Ball Type Flange appears more economical and easier to produce. However, field feedback from actual users and maintenance teams shows a clear trend:
Ball type designs are more prone to flange pullout failures, especially under high loads or poor maintenance.
In contrast, the Cage Type Flange, though slightly more expensive, significantly reduces the risk of catastrophic failure. Users find it more reliable for large-sized fenders (diameter 1 meter and above) used in heavy-duty environments like oil terminals, STS operations, and busy harbors.
Why Customer Experience Should Lead Design Choices
It’s easy to make decisions based on cost and production efficiency. But the real value comes from understanding what customers care about:
Is the pneumatic rubber fender reliable?
Does it last long in rough environments?
Will it fail during critical docking maneuvers?
Technical design should serve real-world performance, not the other way around.
To avoid costly warranty issues and protect their reputation, manufacturers should prioritize the Cage Type Flange for all pneumatic rubber fenders over 1 meter in diameter.
Industry Recommendation for Pneumatic Rubber Fenders Manufacturers
Based on both engineering logic and field feedback, we strongly recommend that all marine rubber fenders manufacturers adopt the Cage Type Flange as the standard for larger pneumatic fenders.
Even if the initial investment is slightly higher, the long-term benefits far outweigh the costs. The Cage Type ensures:
Better force distribution
Higher durability
Safer operation
Stronger customer satisfaction
Protect your fender. Protect your reputation. Choose the right flange.
✅ Key Takeaway
The flange structure is not a minor detail — it’s the anchor of fender reliability. Choosing the right flange type can prevent failure, extend service life, and reduce liability.
🔍 People Also Ask (PAA)
Q1: What is the function of the flange in a pneumatic fender? A: It connects the internal air bladder and external accessories like valves and tire nets, ensuring airtight sealing and load transfer.
Q2: Why do some ship fenders use a cage-type flange? A: Because it better distributes mechanical stress and protects the fender body from damage during extreme loads.
Q3: Are cage-type flanges more durable than ball-type flanges? A: Yes. Cage-type flanges are more reliable in the long run, especially for fenders over 1 meter in diameter.
Q4: Can extruded rubber fenders use similar flange systems? A: Extruded rubber fenders usually have different mounting methods, but flange principles may still apply depending on design.
Q5: What should I look for in marine rubber fenders manufacturers? A: Check if they offer flange customization, certified materials, post-sale support, and experience with ship fenders for your vessel type.
