CHAPTER 51 



Proportions and Shape Data for Typical Ships 



51.1 

 51.2 

 51.3 



51.4 



General Comments 223 



Parent Form of the Taylor Standard Series. 223 

 References to Tabulated Data on Principal 

 Dimensions, Proportions, Coefficients, and 



Performance of Ships 223 



References to Tabulated Data on Yachts and 

 Small Craft 228 



51 . 5 Designed Waterline Shapes and Coefficients . 228 



51.6 Reference Data for Drawing Section- Area 



Curves 230 



51.7 "Standard" Body Plans 231 



51.8 Single-Screw Body Plans 234 



51.9 Twin-Screw Body Plans 236 



51 . 10 Multiple-Screw Sterns 236 



51.1 General Comments. The ship-design 

 procedures of Part 4 are based on the development 

 of each new design as a separate project, to meet 

 the particular requirements set up for it, rather 

 than upon copjdng or modifying existing designs, 

 no matter how good the latter may be. Never- 

 theless, new design requirements often call for a 

 ship hull that resembles one which exists and for 

 which there are proved performance data. It 

 is useful to the designer, therefore, to have pro- 

 portions and shape data which may be consulted 

 for reference and guidance purposes. 



The SNAME Resistance Data sheets were 

 developed, prepared, and issued to fill part of this 

 need, especially for architects and engineers who 

 did not have access to the funds of information 

 available in large ship-design and shipbuilding 

 organizations. Samples of these sheets, filled out 

 with test data for two models of the ABC ship 

 designed in Part 4, are embodied in Figs. 78. Ja, 

 78.Jb, 78.Jc, 78.Ka, 78.Kb, and 78.Kc. The 

 body plans on SNAME RD sheets 1 through 100 

 are rather small, so that the shape data are 

 meager with respect to the data on proportions 

 and model performance. Those on RD sheets 101 

 through 160 are much larger. 



While limitations on space preclude the repro- 

 duction of many large-scale lines drawings in the 

 present chapter, there are given in subsequent 

 sections a considerable number of references to 

 source material embodying such drawings. 



51.2 Parent Form of the Taylor Standard Ser- 

 ies. In view of the recent reworking by M. 

 Gertler of the Taylor Standard Series data, 

 embodied in TMB Report 806 and described in 

 Sec. 56.5, the resistance data from this series are 

 Ukely to be used long after the 1943 edition of 

 D. W. Taylor's book "The Speed and Power of 



Ships" is out of print. Although the body plan 

 and profile of the parent form, and the section- 

 area curves for the series are given in Fig. 28 on 

 page 92 of PNA, 1939, Vol. II, and in the two 

 references mentioned, the complete data from 

 the 1943 edition of S and P are reproduced here. 

 Some editing has been done on the drawing but the 

 model and curve shapes and the numerical data 

 remain unchanged. 



Fig. 51. A embodies the lines of EMB model 632 

 (modified) and the original group of section-area 

 curves, together with the principal proportions 

 and form coefficients. Table 51.a lists the original 

 0-diml offsets for the parent form of Fig. 51. A, in 

 an arrangement somewhat more convenient than 

 those of the references cited in the preceding 

 paragraph, although not as complete as those 

 given by Gertler in TMB Report 806. Table 5 Lb 

 lists the 0-diml ordinates for the complete series 

 of ^4 -curves in the figure. 



51.3 References to Tabulated Data on Princi- 

 pal Dimensions, Proportions, Coefficients, and 

 Performance of Ships. From time to time there 

 have been published tables of dimensions, 

 characteristics, and performance data on ships of 

 many types and sizes. Rarely do these data 

 correspond, for any two tables hsting the same 

 ship(s), and often they omit the very information 

 which the inquiring marine architect desires. 

 Taken by themselves, the data are insufficient for 

 design purposes, and perhaps too meager for 

 statistical studies, but taken together they 

 frequently permit analyses of performance that 

 are extremely useful. 



For example, many of the ships of the period 

 from 1850 to 1900 and later were extremely 

 narrow by modern standards, having L/B ratios 

 of 10, 11, or more. Their B/H ratios were also 



223 



