Diagrams for determining the resistance of single-screw ships

With the aid of the results of many model experiments which have been carried out by the Netherlands Ship Model Basin for upwards of twenty years, attempts have been made at devising a method to determine ship resistance. To this end, investigations have been made with a view to finding out what parameters are of importance for characterizing the ship form and next to ascertaining what influence each of these parameters has on ship resistance. Diagrams are provided for determining the residuary resistance as a function of speed. The construction of these diagrams is described. Moreover, some conclusions are mentioned which could be drawn during the investigations. Finally, the total efficiency of propulsion is given as a function of the number of revolutions of the propeller and the ship’s length. By these means it is possible to derive the ship’s pow er under service conditions from the resistance of the smooth ship, after various allowances have been taken into account.