World Port Development October 201638

e n g i n e e r i n g f e n d e r s

Fenders are an important asset to anyport’s infrastructure, the interface betweenthe ship and the quay is vital to ensuresmooth operations. So, why is it that thereis still a lack of knowledge on their designand components? World Port Developmentreports…

ver the years, we have learnt that fendering systems should not be treated merely as an ‘off-the-shelf ’

commodity but as a knowledge-based product.Whilst the rubber is a very important component within the system, the real craft isin the design of the panels, chains, mechanismsand anchorages, for the most part, fendersare a bespoke system and ship specific.“Clients, end users and even consultantsoften lack the knowledge of what constitutesa good fender system,” said Rob Gabbitas,Engineering Director at QuayQuip, a EurotechBenelux Company.“No two fender systemdesigns will be the same for an oil terminalberth, or a ferry terminal, or a car carrierberth and a barge berth.” Anna-Lena Georg,Marketing Manager at Germany-based ShibataFenderTeam supports such a statement.”Largely unnoticed, mostly overlooked andprobably taken for granted in many ports,marine fenders are actually a thin but cruciallyimportant line between smooth operationsand a substantial insurance claim,” said Georg.“A customised fender design is crucial for the

successful operation of the fender system.Therefore, detailed and extensive design inputshould be delivered by the fender supplier atan early project stage.” One example of acustomised fender solution is given byShibataFenderTeam’s recent project in Malta.Their task was the design of fender systemsfor a liquefied natural gas (LNG) import andre-gasification facility based on a floatingLNG storage vessel.The project had someimportant limitations which they solved withextensive consulting and excellent engineeringwork resulting in a customised fender design.The need for low hull pressure was met withlarge steel panels and softer rubber gradesand the minimum standoff distance wasachieved by customised steel spacers. Each ofthe delivered SPC 1800 Fender systems forthe Regas LNG Plant, Delimara in Malta isable to absorb 3,153 kNm of energy whichwas crucial for a successful operation of theterminal. Richard Hepworth, Business UnitPresident for Trelleborg Marine Systems basedin Dubai, adds that:“High quality fenders arean essential part of port infrastructure,providing protection for terminals and berthingvessels alike.” Trelleborg has previously workedto raise awareness of the performance issuessurrounding lower cost, lower quality fenders,manufactured using low quality rubber compound ingredients.To highlight this issue,two analytical tests were developed byTrelleborg, intended to help buyers determine

the quality of procured fenders.These testsrequire just a small sample from the fenderbody which has no impact on overall fenderperformance. However, prior to testing, there are a number of best practice parameters toconsider in the manufacture of a high quality,engineered rubber fender.According toHepworth:“A rubber compound, producedusing a superior rubber formulation, doesn’tguarantee a high quality fender - one that iscapable of absorbing the correct amount ofenergy. If the mixing process uses inferiorequipment or the process is poorly controlled,the rubber compound will not perform correctly.” In addition, the modulus of rubbercompounds, and the fatigue life of fenders,are dependent on carbon black dispersion,when all other factors are kept constant.This is why Trelleborg suggests the industrymove from using ‘hardness’ to measure energyabsorption, and instead evaluate the uniformityof carbon black dispersion in samples of rubbercompounds and final fenders. (World PortDevelopment will be looking at rubber compounds in greater detail in next month’sissue).“It’s important that designers, operatorsand owners of port infrastructure begin torecognise the importance of rubber compound composition, carbon black dispersion and modulus of rubber fenders.All these factors need to be taken intoaccount during the design and procurementprocess,” said Hepworth.

Setting thestandard

Shibata FenderTeam supplied a customisedfender solution for a recent project in Malta

O

WPD-Oct16-articles 2/10/05 4:14 pm Page 23

October 2016 World Port Development 39

e n g i n e e r i n gf e n d e r s

Ports only create revenue when ships areberthing safely and regularly at their terminals;but if facilities are shut down for fenderreplacement or repair owing to prematurefender failures, then the savings made via the‘cheap’ fenders are often lost in a single day,since daily downtime can account for thousandsof dollars in penalties and revenue loss.“Therefore, it’s important for ports to beinvolved in the selection of the fender supplier,or to pre-approve some high quality suppliersthat can provide proven track records forseveral decades and at least 1,000 installationsglobally. In addition, another important issuefor ports is that the fender supplier shouldhave a product liability insurance as well as aclaim-free record of at least five years,” saidGeorg.“Once you have established a shortlist of high quality suppliers, testing of therubber units has to be addressed.When itcomes to testing of rubber units, there is alot of discussion in the market about howand where to test rubber units.The commonpractice in the industry for decades has beentesting at the point of manufacture, since allthe needed equipment and test rigs as wellas the trained in-house and independenttechnicians are available to make sure testingis performed according to the adapted standards and guidelines.” Georg continuedto support her statement;“As with mostthings in life, you get what you pay for. Highquality and reliability are both important whenchoosing a fender supplier.When fenders failor don’t work properly due to low quality orincorrect designs, then there is a cost to theport in terms of repair, downtime or evenaccidents. However, the failure rate of poorlydesigned fenders systems should not beunderestimated.Typically, whenever fendersystems fail, the culprit is identified veryswiftly - in a good number of cases the rubberunit is the main cause for the failure.Inexperienced suppliers often disregard themost obvious mistakes in fender systemdesigns, like chain angles, especially the weightof the chains, and the position of the rubberunit on the steel panel and substructure.So-called propeller fenders where the rubberunit is placed almost at the top portion ofthe panel in combination with a long steelfender panel will lead to system failures nomatter how good or well tested the rubberunit is.” Shibata FenderTeam offers more than10 different fender types such as cone, cell orelement fenders and foam products. Each typehas specific advantages, and depending on the

project, on-site conditions and preferences ofthe port or their consultants, determines asto which fender type is used.“Just to give anexample, cone fenders with a deflection of70% of its height have the most efficientenergy absorption to fender weight ratio; andsince clients are buying energy absorption,this fender type provides, generally speaking,the most value for money,” said Georg.Clearly, different types of fenders are requiredfor different site conditions and a range ofmarine environments and there is a goodamount of overlap depending on the preference of the client.“Container terminalscan be equipped with cone, cell, element oreven foam fenders. However, foam fendersfor example, are typically used for cruise terminals and naval bases because of thefenders ability to adapt to practically any shipshape and their low-friction and non-markingpolyurethane outer skin.This is particularlyimportant for cruise ships where operatorsdon’t appreciate black marks on a ship’spaintwork [as you may get from a cylindricalrubber fender] for example,” Georg added.

Our research for this article confirmed thatall fender manufacturers agree on the need forfender standardisation. However, this begs thequestion: how can you have standardisationwhen each project needs a tailor-made system?“Long overdue is the appropriate applicationof rubber technology principles and standardsin fender systems, using the same intensity asthose applied in steel fabrication,” saidHepworth.When it comes down to fendertesting Gabbitas told World Port Developmentthat the latest version of BS6349-4:2014 forfenders has introduced a considerable amount of useful guides to consider, but it stops short

of recommendations on testing, as it is essentially only intended for UK use.“Thetesting requirements in PIANC 2002 are full ofinconsistencies, errors, and unclear procedureswhich make it unclear to follow, yet it is generally perceived in the market to be a‘type testing’ standard, which it is not! It isafter all just a guideline!” states Gabbitas.So, with the lack of a ‘proper’ fender standard,perhaps the time has come for each fendermanufacturer to be equipped with their owntesting facilities.“It’s essential that the industryworks towards a deeper understanding ofthe impact of the manufacturing processwhile ensuring that the mixing quality doesnot impact product performance,” saidHepworth.“Port owners, operators,contractors and consultants need comprehensive specifications/testing methodscovering ingredient selection, mixing procedure and production process to stipulate the performance of finished products.It is Trelleborg’s mission to ensure these aremade available, to drive up standards acrossthe whole industry.”

Although fender manufacturers agree thatthe industry needs to set a much higherbenchmark, and collaborate to produce itsown set of standards for testing and designto prevent ‘pop-up’ trading companies delvinginto a market and science they know littleabout, it seems that most still ‘go their ownway’ in order to assure their customers ofgood quality products. Quayquip have pioneered their own durability testing machineand have now completed several orders with3000 cycle compression tests which have beenperformed on actual full size fender units(which may be selected at random by the

Buy cheap, buy twice...

Fender standards Testing facilities

Quayquip installed fenders atStewart World Port - a bulk handling jetty in British Columbia

WPD-Oct16-articles 2/10/05 4:14 pm Page 24

October 2016 World Port Development 41

e n g i n e e r i n gf e n d e r s

client to undergo the most arduous of duties).“We have also invested in the developmentof our range of donut and quayguard foamfenders with the introduction and testing ofnew materials and production techniqueswhich improve the life cycle of the products,”said Gabbitas. For the last six months, Quayquiphas been involved in some interesting projectsincluding the installation of fenders at StewartWorld Port - a bulk handling jetty in BritishColumbia, Canada, which borders Alaska andis ideally located at the end of the deep-waterPortland Canal - within miles of the mostresource rich areas of North America. InAustralia, the company delivered 12 sets of2.8m donuts for a novel application of floatingpontoon corner protection-cum-pontoonrestraint guides at Wheatstone LNG.All unitswere designed, manufactured and model testedin-house by Quayquip to exacting requirements.Their latest project was forSeaspan Ferries, again in British Columbia,for four ferry terminals with the latest generation of Parallel Motion Fenders.Shibata FenderTeam also has the latest andstate-of-the-art test equipment on offer andclaims to be the only manufacturer that doescombined shear and compression testing forfull size and large rubber units, and is fullysupporting testing at the point of manufactureunder the supervision of an independent andqualified third party.“Any other test set-upsoften lack the availability of correct equipmentmeeting the stringent PIANC guidelines,trained and experienced personnel, etc.,” said Georg.“This is particularly the case forthe requirement of domestic testing in certain

countries pushed by some stakeholders.Theinteresting part is that domestic testing ispromoted to ensure performance verificationis done correctly and corresponding testresults can be trusted. However, that impliesvice versa that all fenders delivered outsideof that market cannot be trusted in terms ofperformance which is not only discreditingsuppliers, but also independent test agencies.”Trelleborg has recently undertaken a large-scale study to improve understandingon the impact of curing on the performanceof rubber fenders, which will be published indue course.“The primary purpose of thisresearch has been to develop guidelines thatwill enable the use of optimum fenders in different application areas, and to improveknowledge-sharing and best-practice acrossthe industry,” said Hepworth.Trelleborg’s on-going research into materials best practiceis part of the company’s ‘Smarter Approach’initiative, which is designed to elicit excellenceacross all product ranges and technology

development.Whilst Trelleborg is refocussingits business model towards smart, data-driventechnologies, the company is also keeping akeen eye on the evolution of its current fenderoffering to add the most value to specifiers.The next step in this journey will be deepresearch into testing for specification.Trelleborg is working on a process for ensuring that performance testing can neverbe falsified, with a testing procedure takingspecifiers and buyers through multiple considerations to ensure that the finishedfenders they procure adhere precisely tospecification.With so many manufacturerspulling in different directions and not puttingtheir efforts in to collaboration to establishthe right fender standard, it seems that end-users will have to continue to scrutinisetheir options prior to any fender purchaseand as one particular quote from Georghighlights:“Choose wisely and don’t fall forthe cheapest option - it will cost more overthe long haul.”

Quayquip donut fenders at Wheatstone LNG

Shibata FenderTeam has state-of-the-art test equipment

Trelleborg’s cone fenders

Trelleborg’s on-going research into materials best practice is part of the company’s ‘Smarter Approach’ initiative

WPD-Oct16-articles 2/10/05 4:15 pm Page 26