Sec. 77.41 



PRELIMINARY DESIGN OF A MOTORBOAT 



8f)7 



taining detailed designs and descriptions of 101 

 interesting boats created by 53 American and 

 Canadian naval architects, Oshkosh, Wis., 1953 



(39) Sliaw, P. S., National Researcli Council of Canada 



Reports as follows: 



MB-162, "Results of Tests on a Model of a 27-ft 

 Motor Cutter," 6 Nov 1953 



MB-164, "Results of Tests on a Model of a 27-ft 

 Whaler," Nov 1953 



MB-172, "Results of Tests on a Model of a 27-ft 

 Landing Craft, with Preliminary Pro- 

 peller Dimensions," 25 May 1954 



MB-173, "Full Scale Trials on the RCN 27-ft 

 Motor Seaboat," 4 Jun 1954 



(40) Phillips-Birt, D., "The Design of Sea-Going Planing 



Boats; A Discussion of the Different Types and 

 Their Chai'acteristios," The Motor Boat and 

 Yachting, Jan 1954, pp. 26-31. This article gives a 

 large amount of technical information and some 

 design rules, all in an amazinglj' small space. The 

 following subjects are covered: 



Planing 



Round bilge or chine? 



Displacement and shape of section 



Beam 



The planing angle 



Calculating the power required 



Stepped hulls. 



(41) Beach, D. D., "Power Boat Form," The Rudder, Jan 



1954, pp. 38-43, 90. This is an excellent resume of 

 seven typical modern powerboat forms, represented 

 by lines drawings in each case, with the hydro- 

 dynamic and practical reasons for their various 

 features and characteristics. 



(42) Jacobs, W. R., "Comparison of Hull Resistance for 



'Standard Series' Ships, V-Bottom Motorboats and 

 Flying Boats," ETT Stevens Tech. Memo. 71, 

 Apr 1954 



(43) Phannemiller, G. M., "Modern Design and Construc- 



tion Methods as Applied to 95-Ft Patrol Boats," 

 SNAME, 1954, pp. 643-687. Figs. 2-5 on p. 644 

 give four body plans and bow profiles considered 

 in the design of these boats. 



(44) Corlett, E. C. B., "Trends in Very High-Speed Craft, 



Part 1," The Motor Boat and Yachting, Sep 1954, 

 pp. 386-388; Part 2, Oct 1954, pp. 446-447 



(45) Mason, J., "The Complete Book of Small Boats," 



Bobbs-Merrill, Indianapolis, 1954 



(46) Monk, E., "Weight and the Motor Boat," Yachting, 



Jan 1955, pp. 118-120. The author gives typical 

 percentages for 10 weight groups in the hull only 

 of V-bottom and round-bottom hulls, as well as 

 percentages for 12 groups in the total weight of an 

 "average cruiser." 



(47) Clement, E. P., "Hull Form of Stepless Planing 



Boats," SNAME, Ches. Sect., 12 Jan 1955 



(48) De Groot, D., "Resistance and Propulsion of Motor- 



Boats," Inter. Shipbldg. Prog., 1955, Vol. 2, No. 6, 

 pp. 61-80. There are 9 references on page 77 of 

 this paper. 



(49) Phillips-Birt, D., "Small Craft-Stabihty and Sea- 



kindliness," SBSR, 28 Jul 1955, p. 110. Says that 



Fairmilo B-class rolled uiicoiiifortahly with L = 

 112.0 ft, B = 18.25 ft, L/fi = G.14,andGM = 1.75 

 ft. Later D-class was very much better with 

 L = 110.0 ft, B = 21 ft, L/B = 5.24; "very much 

 lower weights and gi-eater GM." The following is 

 copied from the reference: 



"Unusually stiff small craft have natural rolling 

 periods as short as 3 J- seconds, and 5 to 6 seconds 

 is usual. This means that under a wide range of 

 seagoing conditions, the wave period will exceed 

 that of the boat. The period of a 100-ft wave is 

 about 4j seconds; that of a 250-ft wave is 7 

 seconds. In beam seas these will also be the 

 periods of encounter, while in quartering seas 

 the period of encounter will be greater, by 

 amounts depending on the ship's speed and 

 course. 



"While the period of encounter is longer than 

 the boat's natural rolling periods, small craft tend 

 to roll in the period of the waves. They are, more 

 often than large vessels, in the condition of 

 forced rolling, their motions governed by the 

 prevailing sea rather than their hull form." 



(50) "Design Features of Fast Patrol Boats," The Motor 



Ship, London, Aug 1955, pp. 208-209. The prin- 

 cipal dimensions and characteristics are: 



LoA = 71.375 ft 



LwL = 67.0 ft 



B, molded = 19.0 ft 



B, overall = 19.833 ft 



D, molded, amidships = 10.21 ft 



H, extreme, = 6.083 ft 



L/B = 67/19 = 3.526. 



These craft are driven by twin screws and twin 

 engines of 2,500 horses (shaft power) each. The 

 weight of each engine (presumably dry) and its 

 reverse gear is 10,500 lb. 



These craft are of the V-bottom type, with hard 

 chines and slightly hollow floor sections. The chine 

 line crosses the DWL at about 0.30L from the 

 forward WL termination. 



(51) SNAME RD sheet 116, covering a 74.81-ft by 



13.22-ft by 3.17-ft, 40-kt, PT boat, TMB model 

 3592-1 

 i'52) SNAME RD sheet 147, covering a 30.18-ft by 

 8.54-ft by 1.34^ft, 26-kt, twin-screw pleasure 

 cruiser, ETT model 917 



(53) " 'The Motor Boat and Yachting' Manual," London, 



Temple Press, 1955 



(54) Stoltz, J., "Fundamental Design of Stepless Planing 



Hulls," Motor Boating, New York, Feb-Jun 1956. 

 This is a comprehensive paper which appeared 

 after the writing of the present chapter had been 

 completed. On page 54 of the June 1956 issue 

 there is given an outline of the design procedure 

 for stepless planing craft, in 26 operations. Reprints 

 of the five parts of this paper may be obtained 

 from Motor Boating, 572 Madison Ave., New 

 York 22, N.Y. 



(55) Clement, E. P., "Analyzing the Stepless Planing 



Boat," TMB Report 1093, Nov 1956. 



