What Is Donut Fender?

Monopile Donut fenders shield ships by moving freely with the tide. They attach to a stationary steel monopile, either embedded in the seabed or mounted on the quay wall. In this way, they provide a system that absorbs energy effectively.

Donut fenders are constructed much like foam-filled floating fenders. They consist of closed-cell foam that absorbs energy. The shell is made of polyurethane elastomer and reinforced with a nylon tire cord. The donut fender includes a rigid, galvanized steel sleeve with an internally mounted UHMW pad. This design lets the donut fender slide along the steel monopile. It helps line up a vessel for mooring or guide it through the channel.

Donut fenders are great for use in areas with high tidal fluctuations. They are also suitable for approaching channels, turning structures, and locking entrances. You can also install mooring points or auxiliary fenders outside the donut fender.

Jerryborg Marine manufactures its ocean guard donut fenders in-house. They are available in both standard and custom sizes. Our bespoke options meet your specific requirements and help you achieve your goals.

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Structure of Jerryborg Marine Donut Fenders

  • Central Steel Core: The core, made of durable steel, anchors the fender to the monopile. Due to its design, it withstands physical stress without deforming.
  • Polyethylene Pads: We make the pads from Ultra-High Molecular Weight Polyethylene (UHMW PE). They are designed for lasting performance with low friction and maintenance and ensure a smooth and durable surface.
  • 100% Closed-Cell Foam Core: The foam core provides excellent elasticity and resilience. This is because of its closed-cell structure, which enhances the fenders’ performance. The Donut Fender features exclusively cross-linked closed-cell polyethylene.
  • Closed Cell Foam Core (100%): The molecular structure of closed cells, which isolate gas, maintains the foam core’s elasticity. This feature is fundamental to the performance of foam fenders. Donut Fenders use exclusively cross-linked closed-cell polyethylene.
  • Nylon Filament Reinforcement Layer: Donut Fenders are built with tough nylon filament. It is continuous and thick. It is embedded in the polyurethane skin, providing exceptional strength.
  • Corrosion-Resistant Polyurethane Skin: Polyurethane skin is highly durable. It offers resistance to acids, alkalis, and salt corrosion. This is not the end. You will also get UV protection and non-marking properties. This makes the Donut Fender suitable for many types of weather. It can handle mechanical forces and marine environments.

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Features of Jerryborg Marine Donut Fenders

Features of Jerryborg Marine Donut Fenders
  • Automated Adjustment: Our monopile donut fenders move up and down the monopile automatically. This movement matches the tide, ensuring consistent contact and protection.
  • Advanced Material Technology: They utilize a blend of natural and synthetic rubber. This blend is perfect for optimal shock absorption and long-term durability. This blend works well under UV exposure and saltwater.
  • Impact Energy Management: These donut fenders are designed to disperse the energy from vessel impacts over a wide area. This design feature minimizes stress on the docking structure.
  • Reduced Maintenance Needs: They are constructed in a way that they require minimal upkeep. They are resistant to common maritime environmental damages. Examples include mold, barnacles, and salt corrosion.
  • Easy Integration: Our donut fenders fit easily onto existing monopiles. They don’t need any significant modifications, supporting quick upgrades or replacements.

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Advantages of Jerryborg Marine Monopile Dount Fenders

  1. Enhanced Impact Absorption: Our team uses 100% Closed-Cell Foam to build fenders. These fenders are specialized and designed to absorb significant impact forces.
  2. Gentle Reaction Force: They offer a slower, smoother reaction force duration collision. Their gradual reaction force is more gradual than traditional rugged rubber fenders.
  3. Installation is easy. These fenders feature a design that allows for easy installation. You can effortlessly install them by lowering them onto a pre-driven steel monopile. The monopile has integrated lifting eyes.
  4. Adaptable to Hull Features: Their protrusions from the hull will not damage or break the fenders.
  5. Self-buoyancy: These fenders follow water level changes. This is due to the low-friction guides located inside the fender.
  6. Reliable Buoyancy: Maintains buoyancy and functionality even if punctured.
  7. Easy to Maintain: Reduce ongoing operating costs and maximize lifespan.

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Jerryborg-Marine-Monopile-Dount-Fenders

Donut Fender Technical Performance

Donut Fender Technical Performance
DONUT DIAMETER 4.5 / 1.37 5.0 / 1.52 6.0 / 1.82 7.0 / 2.13 7.5 / 2.29 9.0 / 2.74
FEET / METERS FEET / METERS FEET / METERS FEET / METERS FEET / METERS FEET / METERS FEET / METERS
PILE DIAMETER 2.0 / 0.61 2.5 / 0.76 3.0 / 0.91 3.5 / 1.06 4.0 / 1.22 5.0 / 1.52
feet / meters feet / meters feet / meters feet / meters feet / meters feet / meters feet / meters
PERFORMANCE ENERGY REACTION ENERGY REACTION ENERGY REACTION ENERGY REACTION ENERGY REACTION ENERGY REACTION
ABSORPTION FORCE ABSORPTION FORCE ABSORPTION FORCE ABSORPTION FORCE ABSORPTION FORCE ABSORPTION FORCE
FLAT HEIGHT ft*kip kip ft*kip kip ft*kip kip ft*kip kip ft*kip kip ft*kip kip
feet / meters (kN*m) (kN) (kN*m) (kN) (kN*m) (kN) (kN*m) (kN) (kN*m) (kN) (kN*m) (kN)
2.0 / 0.61 4 18 5 20 7 24 – – – – – – STANDARD CAPACITY
-5 -80 -7 –89 -9 -107 – – – – – –
3.0 / 0.91 6 27 7 29 11 35 15 41 17 44 24 53
-8 -120 -9 -129 -15 -156 -20 -182 -23 -196 -33 -236
4.0 / 1.22 8 35 10 39 14 47 19 55 22 59 32 71
-11 -156 -14 -173 -19 -209 26 245 30 262 43 316
5.0 / 1.52 10 44 12 49 18 59 24 69 28 74 40 88
-14 -196 -16 -218 -24 -262 -33 -307 -38 -329 -54 -391
6.0 / 1.82 12 53 15 59 21 71 29 83 33 88 48 106
-16 -236 -20 -262 -28 -316 39 369 45 391 65 471
7.0 / 2.13 14 63 17 69 25 83 34 96 39 103 56 124
-19 -280 -23 -307 -34 -369 -46 -427 -53 -458 -76 -552
8.0 / 2.44 16 72 20 79 29 94 39 110 45 118 64 141
-22 -320 -27 -351 -39 -418 53 489 61 525 87 627
2.0 / 0.61 7 29 8 34 12 39 – – – – – – EXTRA CAPACITY
-9 -129 -11 -151 -16 -179 – – – – – –
3.0 / 0.91 10 43 11 51 17 58 24 65 27 72 39 87
-14 -191 -15 -227 -23 -258 33 289 37 320 53 387
4.0 / 1.22 13 58 15 68 23 77 33 87 36 96 52 116
-18 -258 -20 -302 -31 -342 -45 -387 -49 -427 -71 -516
5.0 / 1.52 16 72 19 84 29 96 41 109 45 121 65 145
-22 -320 -26 -374 -39 -427 56 485 61 538 88 645
6.0 / 1.82 20 87 23 101 35 116 49 130 54 145 78 174
-27 -387 -31 -449 -47 -516 -66 -585 -73 -655 -105 -786
7.0 / 2.13 23 101 27 118 41 136 57 153 63 170 92 204
-30 -449 -35 -525 -52 -607 -72 -682 -82 -729 -119 -876
8.0 / 2.44 26 113 31 132 47 153 65 174 72 191 106 229
-34 -498 -40 -582 -60 -673 -84 -764 -96 -818 -138 -984

Applications of Jerryborg Marine Donut Fenders

Port and Harbor Protection

Donut fenders provide vital protection. They absorb impact energy from docking ships. They work for both commercial shipping ports and private marinas. They keep vessels and infrastructure safe.

Bridge Pier Protection

These fenders safeguard bridge piers from collisions with vessels. Thus, they reduce the risk of structural damage. They are ideal for bridges located in navigable waterways, enhancing overall safety.

Corner and Jetty Protection

Donut fenders protect docks and jetties’ vulnerable corners and edges. They help prevent damage during vessel maneuvering in tight spaces. This ensures the longevity of dock structures.

Adjustable Tidal Areas

Donut fenders protect dock structures in areas with tidal variations. They do so by moving up and down (vertically) with the tide. This feature maintains optimal contact with vessels, offering continuous protection.

Docking and Berthing Operations

These fenders enhance safety during docking and berthing operations. Thus, they provide a reliable fendering system. They are suitable for smooth operations in both calm and rough water conditions.

Navigational Aid

They act as a visual guide for vessels approaching docking areas. Donut fenders ensure safe berthing and help position ships accurately alongside docks. This reduces the risk of accidents.

Versatile Installations

Donut fenders can be helpful for temporary and permanent installations. They offer flexibility in various maritime projects. They are easy to install and remove, catering to different operational requirements.

Locks and Canals

Donut fenders cushion vessels as they navigate locks and canals. They prevent damage to the vessel’s structure. These fenders are suitable for both big commercial locks and small recreational canals.

Multipurpose Berths

Donut fenders are ideal for multipurpose berths. They accommodate various vessel sizes and types of vessels. Donut fenders ensure consistent protection and reduce maintenance costs for berth infrastructure.

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+86 18765259568

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No.1, Xishanqian Industrial Park, Jimo District 266200, Qingdao City, China.


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