231 



IIVDKODVNAMU.S IN SI 111' 1)1 SICN 



Sec. 1I.S 



tliose for tlic corresponding position on another 

 ship. Tracings of tlie "standard" body plans could 

 be superposed against a \vindi)\v or over a light 

 table to compare the section shapes, section-line 

 slopes, offsets at given stations, and other features. 



However, for hyilrotlynainic analysis, and fur 

 shipniesign purposes as well, tlie.se "13 to 1" body 

 plans do not show the section shapes in their 

 true form nor the section-line slopes at their 

 proper value. It is not possible to coinparc flow 

 patterns by this method since on vessels of the 

 same type the beam-draft ratios may vary from 

 2 to 4, or from G to 10, by ratios that approximate 

 2 to 1 or more. 



Propeller tip clearances, bossing termination 

 angles, and similar features can not be judged or 

 compared easily on these "2 to 1" body plans. 

 Most of the tip circles would be ellipses if drawn 

 properly, and the slopes of bossings and struts 

 would be the same as their true values only if 

 the B/H ratio of the ship were 2.00. 



A more rational and useful scheme is to draw 

 all the "standard" body plans to the same abso- 

 lute width, using as a reference the waterline 

 beam at the midsection or at the section of maxi- 

 mum area. When tracings of these body plans 

 are superposed, the waterline offsets for a series 

 of 10, 20, or 40 stations are directly comparable, 

 as are the drafts and the underwater shapes when 

 referred to the beam. 



The staff of the old Cramp shipyard at Phila- 

 delphia prepared and kept on file a set of three 

 dozen or more of these "standard-width" body 

 plans. Table .51.e lists these plaii.s, ^nth the names 

 and principal dimensions or characteristics of 

 the proposals, designs, and ships involved. All 

 were drawn on tracing cloth, with a standard 

 waterhne beam of 10 inches. The body plans, 

 both underwater and abovewater, were supple- 

 mented (on the same drawing) by tables of prin- 

 cipal ship dimensions, non-dimensional coefli- 

 cients and parameters, and large-scale layouts of 

 the section-area ratios A/Ax and the half-beams 

 of the designed (or load) waterlines. When 

 available, data on model resistances and sliij) 

 elTective powers were added to the sheets. 



Fortunately, although the Cramp shipyard is 

 no more, the Cramp standard jjody plan tracings 

 are preserved in the files of the De]}artmcnt of 

 Naval Architecture and Marine iMigincering at 

 the Ma.s8achu.setta Institute of Technology in 

 Cambridge, Mass. There they maj' be consulted 

 by all who arc interested in them. 



51.8 Single-Screw Body Plans. There are 

 available in the technical literature a few large- 

 scale l)ody plans of nuidels and ships which have 

 acquired prominence in one way or another, 

 either because many tests and trials have been 

 made on tliem, or beca\ise of outstanding good 

 |)erfonnance. Among these may be mentioned: 



(1) G. S. Baker's modol 56C, of which a body plan is 



roproduccil in SBSR, 3 Aug 1916, Fig. 13, p. 107; 

 also in SNAME, 1930, Pi. lOS. EMB model 2933 

 was built to these lines imd tested at Wiushington. 

 The d:iUi are available in S.\AME UD sheet 100. 



(2) German motorship San Francisco of tlie 1930'8, 



owned and operated by the Hamburg-.Vmerican 

 Line, on which a German scientific party mado 

 many measurements and observations at sea in 1934. 

 A body plan of this vessel, with no appendages 

 shown, is published by G. Kempf [SN.\ME, 1936, 

 Fig. 1, p. 197]. On pages 197 through 199 of this paper 

 there are to be found the original observed data 

 from ship and model tests, including open-water 

 tests of the model propeller. Dimensions and other 

 data of ship and model are given in Table 1 on 

 page 196 of the reference. 



(3) Passenger and cargo vessel Panama of 1939, designed 



by George G. Sharp, for which a body plan was 

 published by Marine Engineering and Shipping Age 

 [May 1939, p. 206). 



Fio. 51. D Body Plan for 



coMMis8ir)N Cl-^f-^ VI Ci 



Run or U. S. Maritius 



.A.S.S OK CaUOO VB8SEI< 



