DIFFERENT CARBON FIBRE GRADES
There are generally four grades of carbon fibre used in yacht spars: Standard fibres; Intermediate modulus fibres; High modulus fibres and Ultra high modulus fibres. The laminate design for any mast is directly driven by the grade of modulus of the fibre used for its construction.
In using high modulus fibre, 30% weight savings are possible compared with standard modulus. However as the modulus of the fibre increases the cost rises exponentially.
Further variation is the grade of carbon used. 99% of production carbon spars use Standard Modulus carbon which has a modulus around 230gPa.
However for a very small performance increase and large cost increase, High Modulus carbon can be used. This has a modulus around 340gPa.
The top Finn class masts are made using High Modulus fibre. This is entirely for the dynamic gain as the Standard Modulus masts already come out on the minimum weight.
Carbon is available in different formats, including fabrics, tapes and ribbons. It can be supplied either pre-impregnated with resin (pre-preg) or requiring a separate resin application when you use it (wet lay-up).