Sec. 76.R 



DESIGN OF SPECIAL-PURPOSE CRAFT 



765 



(14) Johnson, Eads, "Ferryboats," SNAME, HT, 1943, 



pp. 172, 174, 179 



(15) Stephens, E. O., "Thames (Dumb) Barges," INA, 



1945, pp. 170-184 



(16) Holt, W. J., "Admiralty Type Motor Fishing 



Vessels," INA, 1946, pp. 295-307 



(17) Wright, E. A., "A Pattern for Research in Naval 



Architecture," SNAME, 1946, p. 374, particularly 

 LCI (L) original body plan in Fig. 14 on p. 384 

 (IS) Aitlcen, R. L., "Special Wartime Prefabrioation 

 Methods Employed hi the Construction of Small 

 Vessels," lESS, 1947, Vol. 90, pp. 246-288, 322-344. 

 Gives many diagrams of small vessels with straight 

 frame segments. 



(19) Emerson, A., "Experiment Work on Merchant Ship 



Models During the War," NECI, 1947-1948, 

 Vol. 64, pp. 289-332, esp. p. 320 



(20) Van Lammeren, W. P. A., Troost, L., and Koning, 



J. G., RPSS, 1948, p. 110 



(21) Thiel, P., Jr., Johnson, R. W., and Ward, L. W., 



"The Resistance and Waive of Nine Double-Chine 

 Simplified Hull Forms," Univ. Michigan Thesis, 

 May 1948. The introduction gives a list of straight- 

 element-form vessels built and in service. 



(22) During World War II a considerable number of small 



cargo vessels, 173 to 176 ft long, were built with 

 straight-element sections and double chines along 

 the bilges. One such vessel is shown in the National 

 Geographic Magazine, Jul 1948, p. 88. 



(23) Bayard, N., "Stock Sloop," The Rudder, Feb 1950, 



p. 44. This craft has 4-sided polygonal frames, from 

 keel to gunwale. It is not known whether the hull 

 surfaces are developable. 



(24) Simpson, D. S., "Small Craft, Construction and 



Design," SNAME, 1951, pp. 554-611, esp. Fig. 21 

 on p. 580. On page 558 the author comments that: 



"As the size increases (above 50 or 60 ft) there 

 would appear to be an excellent field for the double- 

 chine hull form, especially for vessels that operate 

 under varying displacement and trim conditions and 

 in rough waters. There is little difference from the 

 molded (rounded) form in hull characteristics but 

 the double chine with its straight frames and warped 

 (developable) shell surfaces can be built with much 

 less equipment and at a considerable saving in cost." 



(25) Williamson, B., SNAME, 1950, Fig. 19, p. 21 shows 



double-chine corner endings on barges. The 

 developability of these surfaces is not known. 



(26) Examples of straight-element barge and lighter hulls, 



with resistance data, are to be found on SNAME 

 RD sheets listed hereunder: 



(27) Other straighf^eloment forma are illustrated in Figs. 



27.B, 27.C, 08.J, and 72.E of this book 



(28) Pavlenko, G. E., "Soprotivleniye Vody Dvizheniyu 



Sudov (The Resistance of Water to the Movement 

 of Ships)," Moscow, 1953, Figs. 328-336, pp. 

 441-443; also Figs. 337-339, pp. 446-447. Nothing 

 is known of the performance of the straight- 

 element forms represented by the body plans of 

 the figures cited. 



(29) Thames barge tug Jaycee, 62 ft in overall length, 1 6 



ft in beam, and drawing 7.5 ft, has straight,-line 

 frame sections illustrated in SBSR, Int. Des. and 

 Equip. No., 19.55, p. 69 



(30) Some proposed British cargo-ship designs with 



double chines at the turn of the bilge and other 

 straight-element features are shown by E. C. B. 

 Corlett [SBMEB, Nov 1955, pp. 639-641]. 



76.8 Drawing Ship Lines with Developable 

 Surfaces. The principles and the geometry of 

 developable surfaces for boats were, so far as 

 known, first enunciated by C P. Burgess in 

 reference (a) listed hereunder. The graphic 

 procedures for delineating developable surfaces 

 were devised by G. Hartman and others within 

 the next decade, including methods of drawing 

 the customary ship lines in .3-angle or orthogonal 

 projection, when the boundaries are developable 

 surfaces. 



The principal known references are: 



(a) Burgess, C. P., "Developable Surfaces for Plywood 



Boats," The Rudder, Feb 1940, pp. 34-35 



(b) Hartman, G., "Developing a Plywood Design," Motor 



Boatmg, Jan 1945, pp. 82-84, 140 



(c) Hartman, G., "Designing a Sailboat to Use Plywood," 



Motor Boatmg, Jan 1946, pp. 67-69, 218 



(d) Werback, C. E., "More About 'Developable' Surfaces," 



The Rudder, Mar 1945, pp. 30-31, 147 



(e) Losee, L. K., "Developable Surfaces: Their Properties 



and Delineation as Applied to the Shells of Vessels," 

 unpublished manuscript dated 7 Feb 1947. 



As an aid in the shaping of a boat having com- 

 pletely developable surfaces, Fig. 76. D incorp- 

 orates all the data shown by Hartman in Fig. 4 

 of reference (b), with all the original and some 

 supplementary markings. The systematic pro- 

 cedure outlined hereunder is adapted from the 

 instructions pubhshed by Hartman in that 

 reference: 



(1) The principal dimensions and proportions of 

 the boat to be designed are assumed to be selected 

 in advance. These are, for the example given here, 

 expressed in terms of the chine length Lc and 

 the chine beam Be . 



(2) In general, the surfaces may be flat, cy- 

 lindrical, or conical; in this example, only conical 

 surfaces are employed 



