When it comes to deck gear, “big and heavy does not necessarily mean good and safe”, Andy Ash-Vie of Harken told ''MJ''. Further, while there’s some recent moves to reduce its weight this is “often not thought through far enough”.
It’s an interesting conundrum: while specialised industries like oil and gas have developed specific technology with standards to match, the smaller, more general purpose workboats are, by their nature, less regulated and demand even greater flexibility from both equipment and onboard personnel. Unfortunately, the necessary ‘can do’ attitude means a significant number of crew leaves the industry through injury or chronic issues like back strain.
Mr Ash-Vie explained: “There is a very strong argument for minimising weight in manual operations and this is beginning to push changes: while wire has a number of advantages including abrasion resistance, it’s also very heavy, tends to gather snags and it corrodes. People are learning Dyneema is a realistic alternative, it has very high strength without the weight issues and it if it fails, it doesn’t tend to be so catastrophic: there have been quite a number of people killed by the whiplash from recoiling, snapped wire.”
However, he went on to say: “Though there is a trend toward rope, operators aren’t always aware of the whole picture and often try to mix old and new technology, partly because there’s still a deep-rooted resistance to trusting anything lightweight.”
A clear example helps to outline the benefits: “While one vessel that came in had already switched over to Dyneema line, it still had the old, original 142kg pulley block in situ; this took a significant amount of the crew’s combined strength to lift. We replaced it with a 22kg block; although one person can handle it, this has a breaking strain of over 95 tonnes.”
He concluded: “A surprising number of operators haven’t thought about this kind of change which can mean they miss out on around half the potential efficiency available to them.”
Despite Dyneema’s advantages, Mr Ash-Vie also explained that an operator can’t just assume that even a simple piece of equipment will make an easy transition from wire to fibre rope without some care and possible modification: “Obviously fibre does have its own characteristics, chafing is a bigger factor and running on heavily pitted steel surfaces just isn’t good for it.”
It isn’t immediately obvious, but weight itself is a cause of rope chafe. “Heavy pulley blocks will not align under low loads or when taking in the slack in a pull. This leads to the rope chafing on the edge of the pulley - whereas a modern, lighter pulley can self-align through the entire range of loads experienced... avoiding both chafing and jams.
While Dyneema is “relatively new” to workboats, there is a rich seam of information waiting to be mined said Mr Ash-Vie, pointing to the in-depth research established by the competitive sailing sector.
He explained: “What people forget it that the yacht racing world routinely deals with extremely high forces - America’s Cup boats have hydraulic rams driven by pumps linked into the winch pedestals that deal with 10,000 psi, big multihull sail loads can be 50 tonnes - and the sector has had to deal with a number of early issues with Dyneema and Kevlar ropes, for example around the lay pattern, sheave profile and depth of curve.”
It’s also worthwhile noting the R&D, which had developed elements specifically for fibre rope such as grips that are faceted, rather than sandblasted, has also been focused on keeping the weight down through the use of cutting-edge composites. “We can reduce the weight of more traditional lifting equipment by a factor of seven,” he said. “That translates to a really big jump in capability.”
He concluded: “There’s a lot of knowledge and experience already out there that could, and should, make its way across to the workboat industry.”
By Stevie Knight
