Analytical surfaces for ship hulls

Abstract

The choice of optimal shape of ship hull surface is one of the main problems of ship architects and designs. A choice of the form is based on empirical formulae or on intuition of designers. In the article a method of determination of explicit algebraic equations of theoretical shape of ship hull with three main cross-sections given in advance and coinciding with the design waterline, the midship section, and with the main buttock line is given. The forms of the lines in the main cross-sections are chosen from conditions taken in advance. These surfaces are called hydrodynamic. A method is illustrated for three threes of main cross-sections of the ship hulls, i.e. nine hydrodynamic surfaces were constructed. All algebraic equations were converted to parametrical form for comfort of computer modelling. With their help, all nine ship surfaces proposed for the introduction were visualized. Having changed constants containing in the surface equations, i.e. correcting the forms of three main geometric parameters of ship hull, one can select the most rational shape of hull surface for the first approach. Further, it is possible to begin planning parallel middle bodies or to combine bow and stern extremities of a ship from different fragments of algebraic surfaces but with the same midship sections. In a paper, only geometrical problems of design of theoretical hull shape are described.