Abstract
The knowledge of the hull shape and geometry of a racing vessel is one of the most important factors for predicting boat performance. The Offshore Racing Congress (ORC) rating system specifies the calculation parameters of the hydrodynamic forces of boat lift and drag on the basis of input data as the length of waterline while sailing, displacement, wetted surface and the volume distribution along the hull. It is represented by sophisticated calculations for national as well as international events and races. Measurement using a reflectorless total station in a coordinate system defined by the sailboat hull is the most established method approved by the ORC organisation. The determination of these geometric parameters by new, unconventional technologies, which should provide a quicker and more detailed measurement while preserving the quality and accuracy of results necessary for the handicap calculations was our main objective. Geometrical shapes of a cabin sailboat hull were determined by the technology of terrestrial laser scanning and two methods of digital close-range photogrammetry—convergence case of photogrammetry and Structure-from-Motion (SfM) method. High-Definition Surveying (HDS) targets for laser scanning and coded targets for digital photogrammetry were used throughout all methods in order to transform the resulting data into a single local coordinate system. The resulting models were mutually compared by visual, geometrical and statistical comparison. In conclusion, both technologies were considered suitable, however, with various advantages and disadvantages. Nevertheless, although labour intensive, the SfM photogrammetry can be considered the most suitable method if the correct procedures are followed.
Highlights
The knowledge of geometry and shape of the vessel’s hull is the most important factor to predict the performance of the vessel
The points deffiining the main axes of the requuiirreeddccoooorrddiinnaatteessyysstetemmwwereeretatragregteetdedbybythtrheree2e02×0 2×02m0 mmLeLiceaicRaeRtreotrRoeflReecftlievcetiTvaerTgeatrgoenttohne thhuellh(uFlilg(uFriegu4r).e A4)l.soA,lsthoe, tbhaesibcadsioctdtaortgteatrsgeintsthine tfhoermforomf soeflfs-aedlfh-aedshiveesipvaeppearpbearnbdasnwdserweeprleacpeladcoedn othnethuelhl uofllthofe tfihrestfisrasitlbsaoialtb(oSaatt(uSrantu7r2n0—72F0i—guFriegu3)r,ein3)p, rinedpertedrmetienremdincreodssc-rsoescst-isoencstitohnrsouthgrhouthgehhtuhlel (hFuilglu(Freig4u).reH4o).wHeovwere, vdeure, dtoutehteopthoesiptiosnitoiofnthoefstahielbsoaailtboonatthone trhaeilterra,iplelra,cpinlagctinhge pthaepperapbearndbasnadt sthaet tbhoettobmotteoxmactleyxactttlhye aptostihtieonpofsisteiolencteodf pseroleficlteesdwparsocfoilnesidweraasblcyomnsoidreerdaibffilycumlt o(erveendifmfipcuolstsi(belveein itmhepmosisdidble ionf the mhuidll)d.le of the hull)
The final comparison (Figure 19 - the convergence case of digital Close-Range Photogrammetry (CRP) is considered) shows that both technologies—terrestrial laser scanning (TLS) and SfM provide almost identical results
Summary
The knowledge of geometry and shape of the vessel’s hull is the most important factor to predict the performance of the vessel. In order for racing vessels of different sizes and characteristics to compete with each other with the same chance of winning, it is necessary to introduce a unified system of, the so-called “rating“ or handicaps. This rating (handicap) corrects the time differences achieved by the individual racing vessels and puts them to one level. Searching for a perfect rating system is as old as a sailing race itself. Sailors, designers are always trying to find solutions that work alongside the changing design of vessels over time. No matter what rating system is currently being used, the ideal rating system should have the following characteristics: Remote Sens. 2019, 11, x FOR PEER REVIEW
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
