In brief: Carbon fibre based composites have been around in our industry for 40 years, and we have seen more and more use of it in the last decade and that is set to increase further. But why exactly have composites been taking over as the prime material in manufacture of boat parts and phasing out traditional materials such as steel and aluminium?
Each tiny carbon filament can be only 100th of a mm in diameter but when they are spun together, woven into fabrics and impregnated with an epoxy resin matrix, the finished product develops impressive properties.
The high stiffness characteristics of the carbon fibre, plus the ability tailor the fibre directions allows the final product stiffness to range from 8-20 million psi for Standard Modulus Carbon and 14-40 million psi for Ultra High Modulus Carbon that we see in mast construction. To compare to traditional metals, aluminium has a stiffness of approx 10 million psi, and steel 29 million psi.
Similar to the stiffness characteristics, the strength of the carbon epoxy laminate can be tailored to suit the application, with the final product strength comparable to high grade aluminium and steel. The benefit of the carbon epoxy laminate comes from the lower density, which together with the ability to put material only where you need it, the weight benefits can be significant.
To compare carbon laminate with traditional materials we can say:
– Carbon Laminate Strength is comparable to high grade aluminium and steel
– Carbon Laminate Stiffness is comparable to, or greater than aluminium when using Standard Modulus Carbon Fibres
– Carbon Laminate Stiffness is comparable to, or greater than steel when using Ultra High Modulus Carbon Fibres
– For the same volume carbon is 5 times lighter than steel and 1.5 times lighter than aluminium
In addition to these structural properties carbon composites are also far superior in terms of fatigue, have no corrosion issues, are completely versatile in terms of building any form and their electrical conductive properties can be used to assist in the cure cycles.
So in terms of advantages…it’s a clear rationale:
Weight is the obvious advantage, on a motor yacht this can save up to 35% in fuel consumption. Large moving components such as hatches built in carbon can reduce hydraulic pressures and super structures with reduced weight can make huge improvements in stability.
On a racing yacht the weight saving in a hull and deck results in improved speed. A carbon mast will improve stability, reduce windage and weight as well as giving the ability to design exact bend characteristics to extreme accuracy.
For more information about composites refits or new builds please contact the BMComposites office in STP on Info@bmcomposites.com