218 



lIYDROnVNAMHs IN SHIP DllSIC.N 



Src. ''2.7 



(4) Ft>r 7', = l.l.'>. till' sliip is about 1 \v:i\c 

 length loiiR. Tliis is tlic ciusc for some large, fast 

 combatant vessels and for most tugs ami sailing 

 yachts at full or designed speed. 



By the same reasoning, the humps in tlic 

 resistance curves occur when the ship Icnglli 

 corresponds approximately to half-lengths of the 

 transverse wave system. Again roughly: 



(5) For 7', = 0.1)7, the ship is 3J wave lengths 

 long 



(6) For T, = 0.80, the ship is L'l wave lengths 

 long 



(7) For T, = D.'.i'.i tu IdJ, il,(. ship is \\ \v;iv(' 

 length long 



(8) For T, = 1.5 to 1.7, the ship is about \ wave 

 length long. For most destroyers at full speed, 

 nmning at a T, of about 2.00, the ship is some- 

 what less than half a wave length long. 



The values given in the foregoing are drrucii 

 from preliminary examination of published :uul 

 available wave profiles, without a careful study 

 of the effects of bow-wave crest lag. For this 

 purpose, a wave profile shown broadside, for the 

 full model or ship length, is much more ii.seful 

 and valuable than a wave profile shown in its 

 projected position on a body plan. When there 

 is a parallel watcrline portion of considerable 

 length, the po.sitions of the crests and troughs 

 abreast it are not readily apparent in an end 

 view of the hull. 



Figs. 52.1 and 52.J show the wave profiles for 

 five speed-length quotients on each of two 

 models of TMB Series 57, having block coeffi- 

 cients Cfl of O.GO and 0.70, respectively. The 

 body plans and other data for the.se models are 

 given by F. H. Todd and F. X. Forest [SNAME, 

 1951, pp. 042-G9I]. 



Cicneral rules and procedures for predicting 

 the wave profile along a shij) of normal form, in 

 the usual range of speeds, are described in Sec. 

 00.28, using the .VHCsiiij) of Part 4 as the example. 



52.7 Typical Lines-of-Flow Diagrams for Ship 

 Models. Thanks to the work of D. W. Taylor 

 and his as,sociates at the Experimental Model 

 Basin at Washington in the period 1900-1910 

 there appears in the technical literature a mmiber 

 of lines-of-flow diagrams. These are body plans 

 upon which the projected flowline positions are 



Fig. 52.Ka Lines of Flow for Old Cruiseu Model 

 Wove Profiles- 



55. Dolt I more (Old) 

 Via. 52.1vb Lines OK FiAJw Fou Old Cruiser Model 



TABLE .'j2.a— Sini' Dwk fou Mudei.s with Observed Lines ok Flow 

 Thn »hip lonRths and Hpocd.s, except fr>r the Pensacola, are from D. \V. Taylor [SNAME, 1907, j). \\, us are ttie body 

 planH carrying the lines of flow. 



Fig. No. Name or type of vessel 



.'J2.Ku Sun Francixco (old) 



52.Kb liaUimore (old) 



52. Kc Penaacola 



52.L Great Lakes ore steamer 



62. M Collier 



.'i2..Nu Sotoyomo, full speed 



.'i2.Nb Siiloyomo, hIow sfiecd 



.VJ.O Sliidlou'-drafl river Hti-iiiner 



62.1' KiM.-ciiil typo willi bulges 



J^WL , ft 



:iio.o 



;i27.5 

 570.0 

 540.0 

 460.0 



04.0 J 



91. 01 

 257.0 

 490.25 



