{"id":1265,"date":"2026-06-04T01:23:44","date_gmt":"2026-06-04T01:23:44","guid":{"rendered":"https:\/\/zhhmarinefender.com\/?p=1265"},"modified":"2026-06-04T02:46:48","modified_gmt":"2026-06-04T02:46:48","slug":"what-is-a-yokohama-fender","status":"publish","type":"post","link":"https:\/\/zhhmarinefender.com\/nl\/what-is-a-yokohama-fender\/","title":{"rendered":"Wat is een Yokohama-spatbord?"},"content":{"rendered":"

A Yokohama-type fender, more precisely a floating pneumatic rubber fender<\/a>, is an air-filled marine fender that absorbs berthing and mooring energy between a vessel and a jetty, or between two vessels during ship-to-ship transfers. The name is used loosely across the industry, so understanding what it refers to, and what drives its performance, matters more to a buyer than the label. This article covers what the fender is, how it works, how it compares with solid and foam fenders, and how to size and verify one. It does not cover mooring-line design, jetty structural loading, or installation rigging; each of those depends on the specific berth and should be engineered separately.<\/p>\n

What a Yokohama Fender Is ?<\/h2>\n

A Yokohama-type fender and a floating pneumatic rubber fender describe the same air-filled design, whose performance depends on internal pressure and size rather than on a solid rubber body. The type was first developed by the Yokohama Rubber Company of Japan, and the history of Yokohama fenders<\/a> traces the name’s spread from there into general use. The term is widely used in procurement conversations, but the technically precise name is floating pneumatic rubber fender or Yokohama-type pneumatic fender. Strictly speaking, Yokohama is also a company and brand name, so a buyer should confirm the actual manufacturer and the ISO documentation rather than infer origin from the label.<\/p>\n

The most common avoidable error in procurement is treating a Yokohama fender as one fixed product rather than a class defined by size and pressure. When the initial pressure (P50 versus P80) is assumed rather than matched to the berthing energy, a fender can arrive correctly marked and still be wrong for the berth. The naming clears up one frequent question; it leaves the sizing question open, and that one depends on the vessel and the berth.<\/p>\n

How a Yokohama Fender Works: Air-Filled Construction and Energy Absorption<\/h2>\n

A Yokohama-type fender absorbs impact by compressing the air sealed inside a multi-layer rubber body, so the energy it can take up depends directly on its diameter, length, and initial internal pressure. The body combines an inner rubber layer that seals the air, one or more synthetic cord-reinforced layers that carry the load, and an abrasion-resistant outer rubber layer, all vulcanized together. End flanges close each end and carry the inflation valve. Under ISO 17357-1:2014, fenders of 2,500 mm diameter and larger must carry a safety valve that releases excess pressure under accidental over-compression; smaller fenders may carry one if required.<\/p>\n

Because the working medium is air, the fender deflects and conforms to the hull as it compresses, spreading the load so that hull pressure and reaction force stay comparatively low. Low, even hull pressure is the goal: it protects thin-plated hulls and the quay face alike. The angle is what makes this matter in ship-to-ship contact, where two vessels meet obliquely. A pneumatic body holds much of its energy absorption under inclined compression, commonly cited up to around 15 degrees, whereas a solid block loses performance as the angle increases and can behave like a rigid lump under overload.<\/p>\n

The variable to confirm is the initial pressure rating, and the right Yokohama fender pressure<\/a> is matched to the berth rather than assumed. P50 (50 kPa) suits standard berthing and P80 (80 kPa) higher-energy duty such as large tankers, but P80 is not simply an upgrade. For the same nominal size it raises energy absorption and raises reaction force and hull pressure with it, so the berth structure’s capacity and the vessel’s allowable hull pressure must be checked together before selecting it. Choosing the higher pressure by default can return more force into the hull than the structure is meant to take.<\/p>\n

Where Yokohama Fenders Outperform Solid and Foam Fenders<\/h2>\n

Yokohama-type fenders suit large vessels and oblique, ship-to-ship contact better than solid or foam fenders, but whether they are the right choice depends on fender size, budget, and the maintenance access a site can offer. Their strengths are low and even hull pressure, self-buoyancy, and the ability to be deflated and relocated. Their main vulnerability is the air itself: if the rubber skin is breached the fender deflates and loses function, so it needs periodic pressure checks that a sealed foam fender does not.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n
Dimension<\/th>\nYokohama (pneumatic)<\/th>\nFoam-filled<\/th>\nSolid rubber<\/th>\n<\/tr>\n<\/thead>\n
Energy absorption<\/td>\nHigh; air compresses progressively<\/td>\nComparable at smaller sizes<\/td>\nGenerally lower; can drop sharply at overload<\/td>\n<\/tr>\n
Reaction & hull pressure<\/td>\nLow and even<\/td>\nLow<\/td>\nTends to be higher<\/td>\n<\/tr>\n
Inclined \/ STS contact<\/td>\nMaintains performance well<\/td>\nGood<\/td>\nDegrades as the angle increases<\/td>\n<\/tr>\n
Maintenance<\/td>\nPeriodic pressure checks<\/td>\nMinimal; no air to lose<\/td>\nMinimal<\/td>\n<\/tr>\n
Relative cost at large sizes<\/td>\nLower<\/td>\nOften markedly higher<\/td>\nVaries by design<\/td>\n<\/tr>\n
Best fit<\/td>\nLarge vessels, STS, tidal berths<\/td>\nSmaller sizes, low-maintenance sites<\/td>\nFixed quay faces<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

These are general tendencies, not fixed rules, and the full difference between pneumatic and foam fenders<\/a> comes down to the duty at a given berth. For smaller fenders, foam often performs comparably and avoids pressure maintenance, and the cost gap narrows. For large fenders and ship-to-ship work, the pneumatic design usually wins on both cost and hull conformance; industry comparisons commonly note that, at large sizes, an equivalent foam unit can cost several times more. Which one fits should be decided against vessel size, exposure, and inspection access rather than on a single line in a spec sheet.<\/p>\n

Sizing and Pressure: Matching a Yokohama Fender to the Vessel and Berth<\/h2>\n

Selecting a Yokohama-type fender comes down to matching its diameter, length, and initial pressure to the vessel’s displacement, berthing velocity, and the berth’s exposure. Yokohama fender sizes<\/a> run from diameters of roughly 0.5 m up to about 4.5 m and lengths up to around 9 m, depending on the manufacturer and the standard applied. ISO 17357-1 sizes fenders by guaranteed energy absorption, which at its most basic level is a function of vessel mass and approach velocity, so berthing velocity, not diameter alone, drives the choice. The variables that govern the selection:<\/p>\n