In port operations, vessel berthing, and offshore work, the terms mooring and berthing are often used in the same context — and that’s why they are frequently confused. A very common question is: Are marine fenders used in mooring?

In engineering design and real operations, misunderstanding the relationship between marine fenders and mooring systems can lead to poor equipment selection, unbalanced structural loads, and even safety risks. This article explains the real role of marine fenders in mooring from a functional, operational, and engineering point of view.

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1. What Is Mooring?

Mooring is the process of securing a vessel to a quay, jetty, floating dock, or offshore structure using mooring lines, bollards, fairleads, and winches. The goal is to keep the vessel in position under environmental forces such as wind, current, and tide.

The key function of a mooring system is position control — not impact absorption.
It mainly deals with continuous loads caused by wind, current, and wave action.

Simply put, mooring is about holding the vessel in place, not about stopping or cushioning the vessel. That cushioning role belongs to the fender system.

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2. What Are Marine Fenders?

Marine fenders are energy-absorbing devices installed on quays, floating structures, or vessel sides. Their purpose is to absorb berthing energy when a vessel comes into contact with a berth or another vessel, reducing impact forces and protecting both the hull and the structure.

The core function of marine fenders is energy absorption and force reduction.
They mainly handle short-duration, high-intensity loads that occur during vessel contact.

Typical applications include:

• Ship-to-berth operations
• Ship-to-ship (STS) operations
• Floating docks, offshore platforms, and temporary berths

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3. Engineering Selection and Application of Marine Fenders

Although marine fenders are not part of the mooring system itself, they are an essential part of a safe and functional berthing and mooring arrangement. The right fender selection directly affects long-term safety and operational stability.

3.1 Role division between fenders and mooring

System	Main role	Type of load
Marine fenders	Absorb berthing energy, reduce impact	Short-term impact loads
Mooring system	Hold vessel in position	Continuous environmental loads

They don’t replace each other — they work together.

3.2 Common types of marine fenders

• Pneumatic fenders — ideal for ship-to-ship transfer, offshore operations, and temporary berthing; flexible and high energy absorption.
• Cone / cell / arch rubber fenders — commonly used at fixed quays with high berthing energy; robust and durable.
• Foam-filled fenders — suitable for harsh environments or locations where maintenance is difficult.

3.3 Key engineering factors for selection

• Vessel size, displacement, and berthing speed
• Berthing angle and contact method
• Tidal range and draft variation
• Environmental loads (wind, current, waves)
• Type of berth (fixed quay, floating dock, dolphins, SPM)

These factors determine the fender type, size, layout, and how the system interacts with mooring.

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4. Are Marine Fenders Used in Mooring?

Short answer: No — marine fenders are not mooring equipment, but they are a prerequisite for safe mooring.

In practice, the sequence is:

1. The vessel approaches the berth.
2. Marine fenders make first contact and absorb berthing energy.
3. The vessel rests safely against the fender system.
4. Mooring lines are then tensioned to secure the vessel.

Without marine fenders, the vessel would make rigid contact with the quay or another vessel. Impact forces would be transferred directly to the hull and mooring lines, increasing the risk of structural damage and line failure.

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5. Mooring Scenarios That Strongly Depend on Marine Fenders

• Large vessels with high berthing energy
• Ports with strong wind and current
• Ports with large tidal variation
• Ship-to-ship mooring operations (STS)
• Floating docks, single point mooring systems, offshore platforms

In these cases, marine fenders are a key safety component of the overall system.

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6. Common Misunderstandings

• “Marine fenders are only for berthing, not mooring” — this ignores system interaction.
• “Mooring lines alone can protect the vessel” — this is unsafe.
• “Small vessels don’t need marine fenders” — often incorrect depending on conditions.

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7. Conclusion

Marine fenders are not part of the mooring system, but they play a critical protective role at the interface between berthing and mooring.
Marine fenders absorb energy; mooring systems control position. One cushions the vessel, the other holds it in place. Together, they form a complete and safe berthing and mooring arrangement.

Understanding this relationship helps avoid design mistakes, reduces operational risk, and improves overall safety and efficiency.

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FAQ

What are marine fenders used for?

Marine fenders are used to absorb energy and reduce impact forces when a vessel contacts a berth, quay, or another vessel.

Are marine fenders part of the mooring system?

No. They are not part of the mooring system itself, but they are essential for protecting the vessel and structure during berthing and before mooring lines take load.

Can a vessel be safely moored without marine fenders?

In most cases, no. Without fenders, impact loads transfer directly to the hull and mooring lines, increasing the risk of damage and failure.

Which type of marine fender is best for ship-to-ship operations?

Pneumatic fenders are commonly used for ship-to-ship operations because of their flexibility, high energy absorption, and ease of deployment.

Do small vessels need marine fenders?

Yes, depending on environmental conditions, berth type, and operational risk. Fender systems are not only for large ships.