Donut Fender vs Cylindrical Fender: Which Is Better for Your Harbor?​

Donut Fender vs Cylindrical Fender: Which Is Better for Your Harbor?

 

Choosing between a donut fender and a cylindrical fender can determine whether your berth operates safely for 15 years—or suffers costly collisions every 3. Both protect vessels and structures, but their shapes, mounting styles, and performance vary dramatically.

This head-to-head guide breaks down the differences, shows real-world test data, and gives you a clear winner for different harbor scenarios.

 

Design Differences at a Glance

Feature	Donut Fender	Cylindrical Fender
Shape	Ring with central hole	Solid cylinder
Mounting	Slides onto piles/dolphins	Bolts to wall or vertical surface
Load Dispersion	360° radial	Primarily axial
Space Use	Minimal protrusion	Requires flat mounting surface
Installation	Slide-on (fast)	Bolt-down (time-consuming)

 

Performance Comparison 

①Impact Absorption

Lab tests (DNV GL, 2024):

Donut fender: 28% higher energy absorption at 15° oblique berthing angle

Cylindrical fender: Better straight-on compression but weaker at angles

②Lifespan in Saltwater

Donut (EPDM cover): 15–18 years

Cylindrical (same material): 12–15 years

Reason: Donut’s uniform compression reduces stress cracking.

③Maintenance Needs

Donut: Easy slide-off replacement

Cylindrical: Requires dismantling bolts and seals

Ideal Use Cases 

①Choose Donut Fender When:

Berthing dolphins or pile-supported structures

Space is limited

Vessels approach at varying angles

②Choose Cylindrical Fender When:

Vertical wall mounting is required

Straight-on berthing dominates

Budget favors simpler bolt-down installation

③Cost Considerations

Initial price: Cylindrical slightly cheaper (~10%).

Lifecycle cost: Donut wins due to longer lifespan and easier maintenance.

 

FAQ

Q1: Can I mix donut and cylindrical fenders on the same berth?

A: Yes—use donuts on dolphins and cylinders along straight quay walls for optimal coverage.

Q2: Are donut fenders harder to install than cylindrical?

A: No—slide-on mounting takes 40% less labor time.

Q3: Which performs better in icy waters?

A: Donut fenders distribute ice-induced stresses better due to radial compression.