What Are Floating Pneumatic Rubber Fenders?

Floatng Pneumatic Rubber Fenders

Floating pneumatic rubber fenders are air-filled, reinforced-rubber cylindrical buffers that rest on the water surface and absorb berthing impact energy between ship-to-ship (STS) or ship-to-dock (STD) contacts. Also called Yokohama fenders, they follow ISO 17357-1:2014, run at 50 kPa (P50) or 80 kPa (P80) initial pressure, and come in net type, sling type, and hydro-pneumatic configurations.

Why “Floating” Matters

Unlike fixed cell/cone fenders, the compressed-air core gives them self-buoyancy—they rise and fall with tide, track vessel roll/pitch, and need no adjustable brackets. That is why the phrase floating pneumatic rubber fender is not decorative: it is the structural differentiator from solid and foam-filled fenders.

How a Floating Pneumatic Rubber Fender Works (Air-Spring Principle)

1. Vessel contacts the fender at the waterline.
2. Reinforced rubber body deforms; internal air pressure rises uniformly.
3. Kinetic energy converts to air compression + elastic cord-layer strain (up to ~70% absorbed).
4. Reaction force stays low and stable → hull pressure within class-society limits.
5. At 60% deflection (ISO 17357 test point) GEA/R are read from the curve.
6. Load removed → air re-expands, fender recovers shape.

Floating Yokohama Pneumatic Rubber Fenders

Internal Structure: 4 Layers (ISO 17357-1)

• Outer rubber: abrasion, UV, seawater, ozone resistance
• Synthetic tire-cord layer: angled nylon/polyester, burst-proof skeleton
• Inner rubber: air-tight sealing membrane
• End flanges + safety relief valve: inflation, pressure control, auto over-pressure release (mandatory ≥ Ø2500 mm)

Types of Floating Pneumatic Rubbers Fenders

Type I – Net Type (Chain-Tire-Net / Wire / Fibre)

ISO 17357 Type I. Chain + used tires (or rubber sleeves) wrap the body. Best for heavy STS, tankers, LNG, permanent berths. Highest abrasion life.

Type II – Sling Type

No hard net; thick outer rubber + integral slings/lifting eyes. Lighter, non-marking options for yachts/naval/cruise. Quick deploy, lower abrasion resistance.

Hydro-Pneumatic (Subclass)

Part air, part water ballast (~60–70% water) for submerged low-freeboard contact—submarines, special low-hull-pressure ops.

P50 vs P80: Same Size, Different Performance

Never inflate a P50 body to 80 kPa—cord angle and end-ring safety factor differ.

ISO 17357-1:2014 Standard Sizes (Reference)

Range Ø500×L1000 mm to Ø4500×L12000 mm. Example GEA at 60% deflection:

• 2500×5500 mm P50: 943 kJ / 2019 kN
• 3300×6500 mm P50: 1814 kJ / 3015 kN
• 3300×6500 mm P80: 2532 kJ / 3961 kN

(GEA = Guaranteed Energy Absorption, R = Reaction Force; tolerance ±10%)

How to Select the Right Fender

1. Compute berthing energy E = ½ Mₑ V² Cₑ C_m C_s C_c (PIANC method)
2. Set allowable hull pressure + berth reaction limit
3. Match GEA at 60% deflection ≥ computed E
4. Pick P50/P80 by hull sensitivity
5. Pick net/sling by abrasion + marking risk
6. Verify ISO 17357-1 cert, relief valve, marking (ISO part, size, pressure, serial)

Installation & Maintenance Basics

• Inflate with dry air/nitrogen to rated pressure
• Test safety relief valve before deployment
• Monthly pressure check (sun heats +10–15%)
• Inspect cuts >1 cm, exposed cord, net corrosion
• Store deflated, shaded, away from ozone sources
• Service life 10–15 yrs with correct care

FAQ (People Also Ask – AEO block)

Are floating pneumatic rubber fenders the same as Yokohama fenders?

Yes. “Yokohama” is the legacy brand name (Yokohama Rubber Co., 1950s); technically both are floating pneumatic rubber fenders. Spec buyers on ISO 17357, not the brand.

Do floating pneumatic fenders work in high tide ranges?

Yes—self-floating is the whole point; they track tide without mechanical adjustment.

Net type or sling type for LNG STS?

LNG/clean hulls → sling type or non-marking grey net; high-frequency crude STS → chain-tire net.