R&D – the perfect fender
The story about the Damen R&D department and the bow fender of the Fast Crew Supplier 2610 is a story about a search for perfection. Why? Because, in its task of transporting offshore technicians to their place of work, the FCS 2610 bow fender is a critical piece of equipment. Therefore, faced with the lack of a suitable fender on the market, Damen’s R&D department has taken the lead over the last few years to develop the perfect fender.
“These bow fenders need to be multi-faceted,” says Design and Proposal Engineer Brian Mewis. “First of all, they must absorb the kinetic energy of initial impact between the vessel and the offshore structure. After that, they should ‘stick’ to that structure, allowing the vessel’s captain to hold position safely. And don’t forget that this is a very demanding and dynamic environment – the fender needs to be tough enough to cope with vertical movement, while still being soft enough to handle horizontal movements. All of this with one material.”
The challenging working environment means that almost no fender lasts longer than six months. “Though the cost of replacement is not high, crushed and deformed fenders are one of the main problems. There are some that do last longer, but they are not suited to the 2610, which needs softer material due to the lower impact forces involved,” explains Brian’s colleague, Development Engineer Kees van Oosten.
Damen set up a dedicated R&D programme in cooperation with both vessel operators and fender manufacturer Fender Innovations. It has been a process that has involved some intensive in-house testing at 1:5 scale and a considerable amount of data analysis.
The story now continues with exciting news regarding materials and structures. “We found a material – a polyethylene (PE) with just the right properties of strength and toughness that we were looking for, continues Kees.” This crucial step forward was combined with a change in thinking regarding the internal structure of the fender. “It is basically a honeycombed structure as opposed to the conventional method of foam filled fenders. The idea of avoiding foam is to avoid the decline in performance that goes with it. Each impact damages the foam slightly, and it loses its flexibility over time.”
Furthermore, in developing a design, Damen have addressed important safety issues. After all, offshore engineers have to walk across the fender to reach the offshore structure. “We have developed a cover for the fender that will be installed on the central section where the engineers will embark and disembark. Under impact, this mat will deform, but remain in position to ensure a safe foothold,” states Brian.
When asked about the status quo of this R&D programme, Brian and Kees’s enthusiasm for the project shows.
“We have performed a variety of dynamic and static tests to validate the performance of the fender. This also included quasi-static tests to investigate resistant properties as well as impact and tensile tests. These tests have demonstrated that this would be the right material with which to produce full size fenders. As a consequence, we are currently in the process of patenting the design. And then we have operational trials coming up – these will be in cooperation with SeaZip Offshore Services, who have a fleet of six FCS 2610s. Following that, we will be ordering materials for the slightly larger FCS 2710,” Kees explains.
A patented design, a high performance material and full size trials – all the signs are pointing to the successful conclusion of another Damen R&D programme. In turn, this enables FCS 2610 operators to keep doing what they do best – deliver safe, efficient and cost effective offshore access.