The most sophisticated catamaran ever built is under development at Totnes, Devon. The design team’s philosophy is to build a vessel to withstand the most dangerous, unpredictable environments in the world, yet provide a safe and comfortable environment for the crew to live and work in.
Boasting two 130ft high unstayed masts, the weight of the 120ft craft has been kept to a minimum by the use of new composites and design features, such as the absence of rigging – the traditional fixtures and fittings of a racing yacht. With all these unknowns it is essential that such radical design characteristics are subjected to extensive testing.
After four years’ rigorous planning, with a demanding construction schedule ahead, the team has passed a critical point – the testing of a 1/10th scale engineering model to validate the design theory.
A scale mast, complete with sail, was mounted on a custom-designed platform and attached to a vehicle. This sped over the mile-long runway at Chivenor at speeds up to 50mph, simulating the required wind speed. Objectives of these trials were: the precise measurement of the mast/rig loads and bend characteristics; the investigation of a series of designs which are aimed at fully understanding the mast/sail interaction; and the evaluation of whether the actual loads match those predicted.
Strain gauges supplied by Measurements Group UK were bonded onto shear load cell bodies. These were positioned at the base of the scale mast, and were able to monitor the loads in the gimbals which reflect the wind force on the mast. Additionally, a further three strain gauges were installed at the top, middle and bottom of the mast, to measure the strain caused by the mast bending in two axis. The company’s System 5000 data acquisition system set-up in the vehicle recorded signals from the strain gauges and load cells during the high speed runs. These reading were analysed, the wind loadings determined and the results compared with the theoretical figures calculated for the full-size rig.
Measurements Group UK Tel: 01256 462131