Approvals or assumptions?
Ports really need to know more about the fendering and mooring options they choose. Dave MacIntyre and Iain MacIntyre report.
Would the fender industry take a major step forward if an agreed standard was set to guide the design of fender systems globally?
That question is being posed by experts after incidences of damage which have left sometimes quite new fender panels bent and crushed. It points the finger at possible defects in design and potentially exposes a systemic flaw in that ports often lack detailed understanding of fenders.
Ports may also not know how they can make claims to rectify such problems (regardless of expired warranties) and, most importantly, how to prevent future repetitions.
Lack of knowledge extends to the people involved in berthing procedures. One consultant has told Port Strategy there is a clear gap between what port designers produce and the way masters and pilots view the situation.
“During one project, I spent time speaking to pilots and masters who would use the new berth. They had no concept, for example, of what an approach speed of 0.2 m/s or a ten degree approach angle was, let alone mode a, b or c berthing, all as used in the relevant British Standard in the UK,” he says.
Mike Harrison of QuayQuip, a new division of Eurotech Benelux (a Dutch engineering firm with a long history in port and marine construction), is adamant that an industry-wide standard needs to be created.
“A reasonable consensus on a uniform or universal platform for fender design would be a huge step forward,” he says. “At present, specifications or design considerations are often arbitrary values and methods.”
QuayQuip supports greater clarification of key issues for all fender designs, including load factors for normal and extreme events, materials, fender tolerances and temperature factors – all of which could substantially improve the force and stresses compared to figures published in a manufacturer’s catalogue.
To these could be added rules relating to better use of FEA and structural modelling, and proper consideration of bending, shear and local buckling.
“Some codes and guidelines cover some of these aspects, but more often they are omitted from project specifications, and manufacturers do as they please. Ignorant or less scrupulous suppliers will omit some or all of these factors to propose a lightweight, cheap but wholly unsuitable design,” says Mr Harrison.
Lack of agreed industry standards creates difficulties in making comparisons between competing products.
One source says that from a fender specifier’s viewpoint, the comparison of similar products from different manufacturers is difficult: “There is no independent testing data available by which to compare performance. One relies on manufacturers’ own testing, although one is aware that the test regimes may not themselves be the same.”
Buyers, he says, would welcome more performance information. Another concern he has is that cost-cutting or corner-cutting measures are being employed at the performance specification stage.
“[This occurs] particularly when specifying the berthing criteria. But then ports are reluctant to admit that their berths are ‘exposed’ or that the approach to them is ‘difficult’, so less onerous berthing conditions tend to be specified.”
Scott Smith, Asia Pacific regional director for Trelleborg Marine Systems, adds weight to the suggestions that ports need to beef up their knowledge of specifications.
“A greater understanding of fenders and mooring by the ports and those involved in the decision-making process will improve their ability to select suitable systems,” he says.
“In recent years there has been a shift in the structure of the industry. Historically, major manufacturers designed and manufactured fenders in-house, with the exception of some fabrication work. The current trend with new fender suppliers is essentially to act as a sales desk, some with design capacity, focused on marketing. In these cases the design of the fender system may be outsourced, along with the manufacture of all items, to third parties.”
There is a great deal of risk involved with this process, says Mr Smith, as these suppliers have little control over the critical manufacturing process, from design of the rubber compound to the production.
“These suppliers are often reliant on third parties, in developing countries, to be able to understand the operating environment of the fenders and to design the fender and rubber compound to meet these requirements. The result of this process is, more often than not, an ‘off-the-shelf’, rather than bespoke, solution.”
Mr Smith says the design of rubber compounds is a highly skilled and important process in fender design. However, current developments to make cheaper compounds have typically involved using recycled rubber and other low-cost components, affecting the performance of the rubber fender and its life expectancy.
“This is perhaps the biggest issue facing the industry; balancing the influx of low-cost, low-grade solutions, with the need for strong, reliable, high-performance fender systems,” he says.
Another debate is whether fender manufacturers publish sufficient technical information on their product tests for buyers to make an informed decision.
QuayQuip’s Mike Harrison gives a resounding reply: “Absolutely not! It is very clear what information fender manufacturers should publish and the test protocols on which performance should be based. Most of the well-known ‘big’ companies have never bothered to make the necessary investment – probably because their engineering base is so minimal they cannot spare the resources.”
Strainstall marine director Sandy Thomas differs. “Yes, I think we provide sufficient technical information to buyers so that they can make informed decisions and we are always more than willing to discuss any part of our scope in greater detail if required,” he says.
But are clients fair in comparing apples with apples when talking to different suppliers or do they often seem unclear on what their specs need to be?
“I think many buyers are unclear as to what their requirements need to be,” says Mr Thomas. “This probably stems from the fact that a consultant prepares a specification but they are not well experienced in the particular requirements for each system – which, to be fair to them, would be difficult as they often have to deal with marine, electrical, mechanical, instrumentation, telecommunications, etc., for this type of project.”
Chris Millwood, general manager of Maritime International’s Middle Eastern division, also believes there is no shortage of technical information provided by suppliers, but this may lead to more confusion in the selection of fender systems.
“Buyers should beware, as not all of the information available in the market appears to be able to be backed up by actual product testing … with the growing number of applicable performance adjustment factors and assumptions made in fender design (multiple fender contacts, hull radius and bow flare), the general assumption would be that [in] fender submittals, particularly on design and construct contracts, the fenders are not compared on an apples to apples basis.
“In many circumstances, companies who take the specifications to the letter may end up providing a larger fender than their competitors. It is conceivable that the contractor will submit only the cheapest bid from the fender companies, and the client may never be aware of the incorrect assumptions and manipulations that have transpired, leaving them with an under-designed fender system.”
Mr Millwood says a well-equipped fender testing facility, with transparent testing procedures, still remains the best method for determining the performance of the marine fenders. “A fender company’s reputation then lives or dies based on whether the fender systems delivered perform as promised.”
Mike Howie, technology manager for Cavotec MoorMaster, which makes vacuum-based automated mooring technology, points to another issue that is affecting the industry, namely ports chasing increased efficiency, particularly in light of the recession, and looking for equal or more productivity with less resources.
He says conventional mooring continues to pose extreme hazards to port and vessel personnel. “While ports make considerable investments in safety, the intrinsic risks associated with conventional mooring are unlikely to be removed entirely,” he says.
So what should a buyer look for from the manufacturer?
One possible criterion is for fender manufacturers to possess third-party certification to PIANC 2002 type approval guidelines for their products. Even then specifiers and purchasers must beware of certain issues that may invalidate the “type approval”.
Traps to look out for are how recently certification was issued or revalidated; does the type approval encompass all manufacturing plants operated by the maker; are subcontracted fenders covered under the same certification; is verification testing being used instead of type approvals (type approval tests confirm the performance of a rubber unit under a range of conditions, while verification testing only checks the product meets the “datum” value); and does the certification cover the offered fender type?
By carefully checking such data, buyers should at least be clearer as to who they are dealing with.
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