Details

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DD Hollow Rubber Fender | D Shaped Dock Bumper

 

1. Double-D Profile (Outer & Inner Geometry)

• Exterior Shape – D Profile
  • Flat surface allows tight contact with dock walls or vessel hulls, ensuring stability.
  • Curved surface offers smooth berthing interface with reduced friction.
  • Prevents sharp point loading, distributing force across the vessel surface.
• Interior Shape – Hollow D Cavity
  • Hollow cavity decreases fender stiffness, enabling controlled elastic deformation.
  • Provides higher energy absorption per compression cycle compared to solid D fenders.
  • Reduces peak stress loads on both the berthing structure and vessel hull.

🔎 Advantage: The combination of outer and inner D profiles creates a balanced energy/reaction ratio, making it suitable for both small vessels (fishing boats, supply craft) and larger vessels (tugs, barges, offshore support vessels).

 

2. Energy Absorption & Reaction Force Optimization

• Engineered with a compression-deflection curve that ensures gradual increase in resistance as fender compresses.
• High energy absorption capacity – absorbs berthing impacts without damaging the dock structure.
• Low reaction force – minimizes stress on vessel hulls, reducing risk of:
  • Steel denting
  • Paint & coating damage
  • Weld seam cracks

🔎 Performance Benchmark:

• Compared to Solid D fenders, DD Hollow fenders achieve up to 30–40% better energy absorption efficiency.
• Compared to Cylindrical D (DC) fenders, they offer better stability in bolt-through installations and less risk of rolling under side impacts.

 

3. High-Quality Rubber Compound

• Made from a blend of Natural Rubber (NR) and Styrene Butadiene Rubber (SBR) or EPDM compounds, depending on project requirements.
• Key properties:
  • Hardness (Shore A): Typically 65 ± 5 (optimized for marine berthing).
  • Tensile Strength: ≥ 12 MPa for structural durability.
  • Elongation at Break: ≥ 400% to ensure elasticity under repeated compression.
  • Tear Resistance: > 25 kN/m, preventing premature cracking.
  • Compression Set: Low, ensuring long-term shape recovery.
• Additives for Borneo climate resistance:
  • Anti-ozone agents (prevents surface cracking).
  • UV stabilizers (resists tropical sunlight in Sabah, Sarawak & Brunei).
  • Anti-seawater & chemical resistance (withstands continuous exposure to saltwater, fuel, and oils).

🔎 Result: Long service life with minimal maintenance even under 24/7 heavy-duty berthing operations.

 

4. Bolt-Through Installation System

• Integrated Mounting Method: The hollow cavity serves as a bolt passage channel, simplifying installation.
• Advantages:
  • No need for external steel brackets or complicated fixing systems.
  • Ensures firm anchorage to the dock structure.
  • Reduces installation costs and time.
• Compatible with M12–M24 galvanized or stainless steel bolts, depending on fender size.

🔎 Optional: Can be supplied with pre-drilled holes, custom spacing patterns, or mounting hardware kits.

 

5. Size & Customization Flexibility

• Standard Stock Sizes: 2” x 2”, 3” x 3”, 4” x 4”, 6” x 6”.
• Custom Production Sizes: Up to 12” x 12”.
• Length Options:
  • Cut-to-size in 1m, 2m, or 3m sections.
  • Continuous extrusion up to 20m rolls.
• Custom Engineering Options:
  • Curved sections for vessel hull installations.
  • Angled cut ends for dock corners.
  • End caps for neat finishing and water ingress prevention.
  • Colored strips or coatings (optional for high-visibility safety).

 

6. Durability & Service Life

• Designed for continuous compression and relaxation cycles without permanent deformation.
• Resistant to marine growth (barnacles, algae, mussels) – surface can be treated with anti-fouling coatings if required.
• Withstands temperature range of -40°C to +80°C, suitable for tropical Borneo and offshore environments.
• Service life expectancy: 10–15 years with proper installation and maintenance.

 

7. Safety Features

• Smooth outer surface prevents sharp contact damage to vessel coatings.
• Hollow design provides progressive cushioning, preventing sudden jolts during berthing.
• Suitable for all vessel types, from small fishing boats in Semporna to tugboats in Miri and offshore supply vessels in Brunei.

 

8. Testing & Quality Assurance

• Each production batch tested for:
  • Compression performance
  • Tensile strength
  • Hardness (Shore A)
  • Ozone resistance
  • Salt spray testing (for marine bolts and fixings)
• Meets ISO 17357 standards for marine fendering (adapted for extruded fender types).

 

9. Comparison with Other Fender Types

• Solid D Fender: Lower energy absorption, higher reaction force. DD Hollow is superior for protecting lightweight vessels and delicate structures.
• Cylindrical Fender: Provides high absorption but requires more complex mounting. DD Hollow offers simpler installation and neater appearance.
• Arch & V Fenders: Better for heavy-duty berthing of large cargo vessels. DD Hollow is more cost-effective for small to medium berths, fishing ports, and industrial docks.

 

10. Cost Efficiency

• Lower initial cost than larger modular fenders.
• Reduced repair costs by minimizing dock/vessel damage.
• Minimal downtime due to simple installation and long lifespan.
• High return on investment for small ports, fishing harbors, and private jetty operators.