TAKING THE STRAIN

NIGEL SHARP looks at the latest rope tech and what lines suit which jobs on board

- NIGEL SHARP

It was soon after the Second World War that ropes made from synthetic materials such as polyester and nylon, and then later polypropylene, first became available. They had massive advantages over their natural fibre predecessors, which were prone to rot and not very strong, but to achieve high strength and low stretch – in halyards, for instance, and even sheets on larger boats – it was still necessary to use (stainless) steel wire. It wasn’t until the 1980s when Kevlar was first used in rope construction that there were any further developments in terms of materials. Since then a bewildering range of additional high-tech materials have appeared, including Dyneema, Vectran, Technora, Cordura, Zyex and Zylon, which have allowed rope manufacturers to produce increasing numbers of different products. Pure polyester ropes are still available and can adequately perform a general purpose role in different running rigging applications, particularly on cruising boats and club racing boats, but the more serious racers have plenty of opportunities to use different products which have been developed for specific applications. Amongst the more important considerations when selecting a particular type of rope are its intended application – sheet, halyard, kicker, runner and so on – and also to what extent it will need to integrate with deck and rig fittings such as winches, jammers and sheaves. It is important to select the right product and it is very easy to select the wrong one.

The most commonly used of the high tech materials is Ultra-High Molecular Weight Polyethylene (UHMwPE), easily the best known of which is Dyneema, which is supplied by Dutch company DSM. Dyneema has been available in various forms but the three which are currently commonly available are SK78, SK99 and DM20. Not only is Dyneema extremely strong – 10 times stronger than steel per unit of weight and twice as strong as Kevlar – but it also has excellent stretch