29 July 2014
29 July 2014
CarbonicBoats new L/V design for carbon fibre (CF) composite dagger board and rudder hydrofoils have been used successfully in this year’s race.
The Championship took place in New Zealand at Takapuna, North Auckland, with boats retrofitted with these latest design L carbon fibre epoxy rudders with lifting and stabilising foils coming 1st, 2nd, 3rd and 5th in the International A division.
Developed by CarbonicBoats. the novel, ‘Paradox’ branded composite rudders are referred to by the company as heave-stable 'L' foils (L foils for short). Each of the epoxy carbon foils in the set was low temperature moulded using GMS EP-270 epoxy prepreg system, manufactured and supplied by Australian-based GMS Composites.
Competitive racing vessel designs must strictly comply with the international development A class rules, which limit boat dimension to: length 5.5m (18ft), beam 2.3m (7.5ft) and a sail area of 13.9 sq.m (149.6 sq.ft). Rigging and all appendages must also comply with race rules. Boats typically have a carbon fibre mast with a height of 9m (29.5 ft), with the two hulls constructed from a carbon / aramid honeycomb sandwich epoxy laminate. The overall weight of a finished rigged catamaran, ready to race is 75Kg (165lbs).
“For our L/V foils, stiffness, accuracy, dimensional stability, reliable consistency in performance properties and a very high quality surface finish are all very important. Using GMS EP-270, we can fabricate foils 2% thinner than competitive foil designs, with a trailing edge thicknesses sub 1mm. This is only possible with a good stable resin matrix. GMS prepregs allow us to accurately replicate the specified design characteristics with no needed to compromise, and finished parts remain stable in use.”
“GMS prepregs have good ‘tack’ so they can be easily positioned and worked into curves for efficient mould, with a relatively short recommended cure time of only 60 mins at our preferred 110 0C mould temperature, with the ramp up and dwell times overall being shorter than the previous low temperature epoxy system used”commented Dario Valenza, founder of CarbonicBoats.
According to CarbonicBoats, improvements in stiffness and foil stability were achieved with GMS epoxy prepreg material; for the same section shape and fibre stack, the finished foils fabricated from GMS EP-270 showed 8mm less deflection over an 800mm span when subjected to a weight-bend test on the bench. The higher mechanical performance of the GMS Composites epoxy carbon laminate system combined with the proprietary design and shape of Paradox L/V foils enables a single dagger foil to support the full weight of the boat plus the dynamic loads when racing at high speed. The design of the rudder foils is somewhat different, having shorter chords, thinner sections and greater span, with more slender elevators (so more bending moment), being overall 5% lighter and with a lower failure rate.
Photo provided by GMS Composites