Sea Cushion Fenders: A Complete Guide

Introduction

When it comes to reliable protection during vessel berthing, sea cushion fenders stand out as one of the most trusted solutions. Also known as foam fenders, they are widely used in ports, offshore projects, and ship-to-ship (STS) operations. Their ability to absorb high energy while keeping reaction force low makes them essential for modern marine operations.

This article will explain what sea cushion fenders are, how they work, their construction, advantages, applications, and how they compare to other fender types.

What Are Sea Cushion Fenders?

Sea cushion fenders are another name for foam-filled fenders. Instead of using compressed air like pneumatic fenders, they are built with a closed-cell foam core that absorbs impact energy. The foam material prevents water ingress even if the outer skin is damaged, ensuring long-term durability.

These fenders are often covered with a tough polyurethane skin and sometimes equipped with a protective chain and tire net for heavy-duty use.

How Do Sea Cushion Fenders Work?

The working principle is simple: when a vessel presses against the fender, the foam inside compresses and absorbs the impact energy. The outer elastomer skin helps distribute the pressure evenly, while the closed-cell foam prevents permanent deformation.

Because of this design, foam filled fenders deliver both high energy absorption and low reaction force, protecting both ships and berthing structures.

Construction and Materials

A typical sea cushion fender is made of three main layers:

1. Outer Skin – Usually a tough polyurethane elastomer, resistant to UV, seawater, and abrasion.
2. Reinforced Layer – Optional reinforcement (nylon or synthetic fabrics) improves strength.
3. Foam Core – High-density closed-cell foam that absorbs impact and prevents water penetration.

This simple yet durable structure makes the fender safe, long-lasting, and maintenance-friendly.

Specifications and Performance

Sea cushion fenders are available in various sizes, diameters, and energy-absorption ratings. Common parameters include:

• Diameter & Length – Determines energy absorption capacity.
• Energy Absorption (EA) – The amount of energy absorbed during compression.
• Reaction Force (RF) – The force returned to the ship or structure.
• Density of Foam – Higher density for heavy-duty use, lower density for lighter operations.

Manufacturers usually provide energy-reaction (E/R) curves and technical data sheets to help buyers select the right model.

Advantages of Sea Cushion Fenders

Compared with traditional rubber or pneumatic fenders, foam fenders offer several benefits:

• Unsinkable – Even if the skin is damaged, the foam keeps functioning.
• Durable – Resistant to punctures, UV radiation, and seawater corrosion.
• Low Maintenance – No air pressure checks required, unlike pneumatic fenders.
• Flexible Use – Can be installed on fixed structures or used as floating fenders for STS.
• Long Service Life – Typically longer lifespan than conventional fenders.

Applications of Sea Cushion Fenders

Sea cushion fenders are widely used in both port and offshore operations:

• Ship-to-Ship (STS) Transfers – Oil, LNG, and bulk cargo operations.
• Ship-to-Dock (STD) Berthing – Protecting vessels and terminals during mooring.
• Naval and Defense – Military ports, warships, and submarines.
• Offshore Projects – Support for oil rigs, floating structures, and wind farm installations.
• Temporary Mooring – Barges, tugs, and floating docks.

Their versatility makes them a go-to solution across different marine industries.

Comparison with Other Fender Types

Sea cushion fenders differ from other common fenders in several ways:

This comparison shows why foam fenders (sea cushion fenders) are often chosen for critical operations.

Frequently Asked Questions (FAQ)

Q1: Are sea cushion fenders the same as foam fenders?
Yes, sea cushion fenders are another name for foam-filled fenders.

Q2: Do they require inflation like pneumatic fenders?
No, they are solid foam inside and do not rely on air pressure.

Q3: What happens if the outer skin is damaged?
The foam core is closed-cell, so the fender will not sink and continues to work.

Q4: How long do foam fenders last?
With proper use, they can serve for 10–15 years or more.

Q5: Can they be used in extreme environments?
Yes, they are resistant to UV, seawater, and temperature changes, making them suitable for offshore projects.

Conclusion

Sea cushion fenders, also known as foam fenders, are a proven and reliable solution for ship and port protection. With their high energy absorption, unsinkable design, and low maintenance requirements, they are ideal for both STS and STD operations.

For shipyards, ports, and offshore operators looking for long-term reliability, foam fenders are an investment that ensures safety, durability, and peace of mind.