{"id":1265,"date":"2026-07-23T01:23:44","date_gmt":"2026-07-23T01:23:44","guid":{"rendered":"https:\/\/zhhmarinefender.com\/?p=1265"},"modified":"2026-07-23T07:52:23","modified_gmt":"2026-07-23T07:52:23","slug":"what-is-a-yokohama-fender","status":"publish","type":"post","link":"https:\/\/zhhmarinefender.com\/ko\/what-is-a-yokohama-fender\/","title":{"rendered":"\uc694\ucf54\ud558\ub9c8 \ud39c\ub354\ub780 \ubb34\uc5c7\uc778\uac00\uc694?"},"content":{"rendered":"

A Yokohama fender is a floating pneumatic rubber fender<\/a>: an air-filled marine fender used between a vessel and a jetty, or between two vessels alongside each other, whose energy absorption depends on diameter, length and initial internal pressure rather than on the brand name it carries. Fenders of this class are built and tested to ISO 17357-1:2014, which covers high-pressure units at 50 kPa and above and defines two pressure grades, P50 and P80. The name is used loosely across the industry, so the label alone tells a buyer very little. Which unit belongs at a given berth depends on vessel displacement, approach velocity at first contact, and the reaction force the berth structure can accept.<\/p>\n

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

The Yokohama fender name covers a family of floating pneumatic rubber fenders rather than one fixed product, and whether a given unit suits a berth turns on its size and pressure grade. The type came out of the Yokohama Rubber Company in Japan, and the history of the name<\/a> explains how it spread from there into general use. The precise term is floating pneumatic rubber fender, or Yokohama-type pneumatic fender. Listings often spell it yokahama or yokohoma; these refer to the same product. Yokohama is also still a company name, so a buyer checking provenance should confirm the actual manufacturer and the ISO documentation rather than read origin into the term.<\/p>\n

Treating the name as a single specification is the expensive mistake. Two units carrying it can differ by an order of magnitude in the energy they absorb and in the force they push back into a hull.<\/p>\n

A pressure grade carried over from an earlier project, because the vessel class looked similar, is the common route to that error. The fender arrives correctly marked and still returns more reaction force into the berth than the structure was designed to take. The first corrective step is to repeat the fender-system selection against verified berth data. Depending on what that shows, the outcome may be a different pressure grade, a different size, more units, a revised arrangement, or a limit on approach speed.<\/p>\n

\"Yokohama<\/p>\n

What Air as the Working Medium Sets, and What It Limits<\/h2>\n

Because a pneumatic fender absorbs impact by compressing sealed air rather than by deforming solid rubber, its energy absorption, its hull pressure and its failure mode all trace back to one variable: the internal pressure it holds at the moment of contact. The body is straightforward. An inner rubber layer seals the air, synthetic cord-reinforced layers carry the load, an abrasion-resistant outer layer takes the wear, and end flanges close each end and carry the inflation valve. Under ISO 17357-1:2014, fenders of 2,500 mm diameter and above must carry a safety valve to release excess pressure under accidental over-compression.<\/p>\n

Air also lets the fender conform to a hull as it compresses, spreading the contact so that hull pressure and reaction force stay comparatively low. That matters most where two hulls meet obliquely, as they do in ship-to-ship work<\/a>. Yokohama Rubber’s technical catalogue reports no reduction in energy absorption for its pneumatic fenders under inclined compression up to 15 degrees, in the configurations tested. A solid block loses performance as the angle opens up. Whether a particular unit behaves that way is a question for its own type-approval data.<\/p>\n

Air behaves differently from rubber in one respect that rarely reaches product literature. Pressure in a sealed body of roughly fixed volume rises and falls with absolute temperature. A fender inflated on a cool quayside and then left in direct sun is no longer sitting at the pressure it was set to. That makes the measurement procedure part of the specification: readings should be taken and interpreted using the manufacturer’s inspection and temperature-correction method, and a reading outside the permitted range needs investigating. Warm weather is not an explanation for it. The safety valve is a separate matter. On fenders of 2,500 mm and above it limits pressure during accidental over-compression, which is a mechanical event rather than a thermal one.<\/p>\n

Pneumatic Against Foam and Solid: Where Each Type Wins<\/h2>\n

A pneumatic body suits large vessels and oblique ship-to-ship contact better than foam or solid rubber, though the right choice at a given berth depends on unit size, inspection access, and whether anyone will realistically check pressure on a schedule.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n
What it decides<\/th>\nPneumatic (Yokohama-type)<\/th>\nFoam-filled<\/th>\nSolid rubber<\/th>\n<\/tr>\n<\/thead>\n
Behaviour under overload<\/td>\nReaction force rises progressively, within rated compression and valve capacity<\/td>\nProgressive<\/td>\nCan stiffen toward a rigid block<\/td>\n<\/tr>\n
Hull pressure<\/td>\nLow, spread across the contact<\/td>\nLow<\/td>\nTends to be higher for comparable energy<\/td>\n<\/tr>\n
Oblique \/ STS contact<\/td>\nHolds performance under inclined compression<\/td>\nGood<\/td>\nFalls off as the angle grows<\/td>\n<\/tr>\n
What puts it out of service<\/td>\nLoss of air through a breach in the skin<\/td>\nSkin damage; no air to lose<\/td>\nWear, and failure at the fixings<\/td>\n<\/tr>\n
Routine attention<\/td>\nPeriodic pressure checks<\/td>\nMinimal<\/td>\nMinimal<\/td>\n<\/tr>\n
Typically suits<\/td>\nLarge vessels, STS, wide tidal range<\/td>\nSmaller sizes, limited inspection access<\/td>\nFixed quay faces<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

These are screening-level tendencies for narrowing a shortlist. They do not replace project-specific performance calculations, and any row can be overturned at a particular berth by design energy, contact area, tidal range, shear and abrasion exposure, puncture risk, spares availability or whole-life cost.<\/p>\n

\"Floating<\/p>\n

The overload row repays following through, because it redistributes risk instead of removing it. When a solid fender stiffens under excess load, the energy it stops absorbing arrives in the hull plating and the quay face as reaction force. A pneumatic body goes on absorbing further into the stroke, though not without limit: it has a rated compression, its flange geometry has a design envelope, and its safety valve has a finite venting capacity. So the binding question on a pneumatic unit is usually about the force it returns, and sizing up is not automatically the safer move.<\/p>\n

At the smaller end of the range, and at berths where nobody is realistically going to check pressure on a schedule, a foam-filled unit<\/a> is often the better buy. There is no air to lose, and both types can usually be sized for the energy involved at that scale. Whether that holds at a given berth still depends on design energy, available contact area and whole-life cost, and cost comparisons run in both directions depending on size and quantity.<\/p>\n

Net Type or Sling Type: Matching the Fitting to How the Fender Will Be Handled<\/h2>\n

Fitting type is a separate decision from size and pressure, and it turns on how often the unit will be moved and how much abrasion the berth will put on it. Net type fenders sit inside a chain, wire or fibre net, usually with tyres or rubber sleeves, which suits fixed and semi-permanent positions where abrasion is the main threat. Sling type units carry a lifting device at each end connected by guy chain or rope, weigh less, and are quicker to recover and redeploy.<\/p>\n

\"Diagram<\/p>\n

The practical question is redeployment frequency against abrasion exposure. A fender that stays on one berth for years earns its net. One that moves between operations, or gets recovered ahead of weather, is easier to live with as a sling type, provided the lifting arrangement on site can handle it.<\/p>\n

On tidal berths with a wide water-level swing, the guy chain and the end-fitting shackles tend to be the parts that come up for re-inspection first. They carry the cyclic movement the fender body is there to absorb. How that fitting is then rigged, meaning chain length, attachment points and stand-off geometry, is a separate exercise from choosing the fender and belongs with the berth’s installation drawings.<\/p>\n

Sizing and Pressure: Which Variable to Confirm First<\/h2>\n

Sizing a Yokohama fender starts from berthing energy rather than from a diameter, and berthing energy is set by the vessel’s displacement, its approach velocity at first contact, and the contact geometry at the berth. Two documents divide the work. ISO 17357-1:2014 governs the product: construction, minimum performance, dimensions, testing and documentation, including guaranteed energy absorption for standard sizes. Project-level selection is a separate engineering exercise, governed by the berth design criteria and by guidance such as PIANC Report No. 211, PIANC Fender Guidelines 2024, which covers the design, manufacturing and testing of fender systems and supersedes the earlier WG 33 guidelines. The product standard specifies two initial pressure grades<\/a>, P50 at 50 kPa and P80 at 80 kPa. For the same nominal size, P80 offers higher guaranteed performance and raises reaction force and hull pressure with it. Select it only where those figures stay inside what the berth structure and the hull can accept.<\/p>\n

Approach velocity at first contact is the variable to pin down first. In the basic kinetic relationship behind berthing energy, energy scales with the square of velocity and only linearly with mass, so an assumed approach speed moves the answer further than an assumed tonnage does. Project design energy is more than that expression. It also carries the added-mass, eccentricity, softness and configuration coefficients and the safety factors the governing design method requires. The asymmetry between velocity and mass survives into it. PIANC’s 2024 guidelines make the same point from the other direction. Site-specific berthing data, taken from pilots and harbourmasters instead of assumed, can justify a smaller fender than a generic figure would; ignoring it tends to produce an overdesigned one.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n
Variable<\/th>\nWhat it sets<\/th>\nWhen to confirm it<\/th>\nChangeable after manufacture?<\/th>\n<\/tr>\n<\/thead>\n
Approach velocity at first contact<\/td>\nBerthing energy, scaling with the square of velocity<\/td>\nFirst<\/td>\nNo<\/td>\n<\/tr>\n
Vessel displacement<\/td>\nBerthing energy, scaling linearly<\/td>\nFirst<\/td>\nNo<\/td>\n<\/tr>\n
Allowable reaction force at the berth<\/td>\nConstrains the whole system: grade, size, quantity, spacing, arrangement<\/td>\nBefore any grade or size is fixed<\/td>\nNo<\/td>\n<\/tr>\n
Hull pressure limit for the vessel class<\/td>\nConstrains grade, size and contact area<\/td>\nBefore any grade or size is fixed<\/td>\nNo<\/td>\n<\/tr>\n
Diameter and length<\/td>\nGuaranteed energy absorption available<\/td>\nOnce the design energy exists<\/td>\nNo<\/td>\n<\/tr>\n
Fitting type (net or sling)<\/td>\nHandling effort and abrasion resistance<\/td>\nLast<\/td>\nSometimes, subject to body design, end fittings and manufacturer approval<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\"Diagram<\/p>\n<\/div>\n

Published Yokohama fender size ranges<\/a> vary by manufacturer. What decides anything is the guaranteed energy absorption on the datasheet for the specific unit, read against a design energy figure.<\/p>\n

ISO 17357 Compliance and What to Check on Delivery<\/h2>\n

ISO 17357-1:2014 is the standard a Yokohama-type fender is certified against, and it governs the product: material, performance, dimensions, and the test and inspection procedures behind the certificate. It was reviewed and confirmed in 2024 and remains current. Part 2 covers low-pressure fenders, and the two parts together replaced the 2002 edition, so references to other years in product listings are worth checking against the current text. PIANC sits on the other side of that line. Its 2024 guidelines govern how a system is designed, manufactured and tested for a berth. PIANC also states plainly that it certifies nothing, so a listing advertising “PIANC certified” fenders is describing something that does not exist.<\/p>\n

One requirement in the 2014 revision repays reading for what it implies. The standard limits the diameter of the bead ring and other steel around the flange opening so that the metal does not take a permanent set when the fender is compressed close to 80 percent. A requirement framed that way treats near-limit compression as something a working fender will meet. What follows from it is an inference rather than a clause. Because the flange and bead geometry is controlled specifically for severe compression, those areas belong in the manufacturer-approved inspection after a heavy contact. An intact outer skin says little about them. The standard also expects prototype performance confirmation to be repeated on a ten-year cycle, which is a question about the model being offered rather than about the individual unit.<\/p>\n

Unfolding a fender on the quayside and checking it against the order takes an hour. Discovering at the berth that the pressure grade marked on the body is not the one the berthing-energy calculation assumed costs considerably more.<\/p>\n