Remodelling Scarlet Oyster’s Keel
Spring 2011
Oyster Lightwave 48. The boat is owned by Ross Applebey and raced competitively with a good record of success, including a win in the Fastnet Race 2007. Ross’s design brief was to improve the boats performance to windward by remodelling the existing lead keel. The project was managed by the owner, who also carried out the construction work. Draughtmark provided scanning and design services.
Rhinophoto, a photogrammetry plugin for Rhinoceros 3D modelling software, provided an accurate, cost effective way to produce a working model of the existing keel.
Using a good quality digital camera, photographs are taken to capture data to be processed to recreate a 3D model of the existing keel. The technique can be used to reverse engineer a wide range of objects. Photogrammetry is a cost effective alternative to laser scanning. Rhino is perfectly suited to utilise the accurate 3D data points to continue the modelling process
The targets are analysed by Rhinophoto and used as reference points by the designer when creating curves and surfaces to generate the 3D model.
The ability to superimpose the 3D model onto photos of the existing keel assists the verification process
The model was used to inform design decisions and create output for performance analysis, prior to physical construction of the new keel. Once happy with the design, the owner submitted proposals and drawings to RORC to obtain a rating number.
The model formed the basis for drawings for construction of a mould to reuse lead from original keel. An internal Stainless Steel framework was designed for a new composite section of the keel.
At the time of writing, Ross has enjoyed good results in the 2011 race season.