Shortage of carbon fibre

Robert Deaves looks at a major problem globally facing race boat, dinghy and spar manufacturers
Material Tensile Strength (GPa) Tensile Modulus (GPa) Density (g/ccm) Specific Strength (GPa) Standard' carbon fibre 3.5 230 1.75 2 High tensile steel 1.3 210 7.87 0.17 Kevlar 3.6 60 1.44 2.5 E-glass 3.4 22 2.6 1.31 Carbon fibre/epoxy, through its attractive properties of high strength/modulus and light weight compared to regular GRP or traditional materials like steel or aluminium, is now a familiar feature of racing yacht and dinghy construction. Carbon fibre spars have over the last decade moved from solely the realms of race boats to cruising yachts, while America's Cup Class yachts, maxi-multihulls, Volvo Open 70s, Open 60s, 60ft trimarans, TP52s all the way down to Olympic Tornados are today built almost in their entirety using some form of carbon fibre construction. Thus it comes with some alarm that a global shortage of carbon fibre has hit many manufacturers hard as they struggle to keep their stocks high enough to meet the ever increasing demand from boat owners. The shortages are forcing some manufacturers to streamline and prioritise their operations, and in some cases redesign their products using the limited materials that are available. Concern was first voiced more than a year ago that shortages of carbon fibre were about to hit world stocks, but so far its effect has been limited and most customers are blissfully unaware that there is a problem. As one mast manufacturer commented, “I don’t think that the market realises how hard it has been to source materials.” But demand has been outstripping supply for several years and for some manufacturers, the situation has now reached critical point. Carbon fibre The majority of carbon fibre used in marine applications is PAN-based fibre, made from an acrylic fibre precursor called polyacrylonitrile (PAN) which is carbonised through exposure to extreme heat (ie <3,000degC) and subsequently oxidised gaining its familiar black colour. Many masts are also built from prepreg cloth - woven carbon fibres impregnated with uncured thermosetting resins which cure at temperatures