of a digital computer routine which could be used to compute the parameters. The data to be 

 furnished to the computer are discussed in detail. Parts of the task, the examination of ship 

 scantlings and the tabulations of basic data, will remain manual operations not included in 

 the program. The input forms for the digital computer program should also serve the auxiliary 

 purpose of assisting in the orderly and efficient recording of the basic data. Data input is 

 prepared on cards and the computer calculates parameters for one ship section at a time. The 

 output of the program gives the internal shear flow (stress) distribution (in the hull, per unit 

 beam shear or torque) in addition to the parameters needed in the beam equations. The pro- 

 gram has been written in FORTRAN^ '^ and can be used on IBM 650, 704, 709, or 7090. 



To test the program, a hand and digital computer calculation is compared for a sample 

 problem. 



The method has been developed for bodies with a plane of symmetry (typical of most 

 ships) and also for the general case where there is no symmetry. 



The report has been organized to meet the needs of the program user. 



DATA TO BE FURNISHED TO THE COMPUTER 



GENERAL 



Based upon a theory presented in Appendix A, a digital computer program for calculat- 

 ing the section properties (i.e., equivalent beam parameters) of ship hulls, presented in 

 Appendix B, has been devised. Computation of these parameters requires that certain data 

 (geometry, areas and thicknesses, effectiveness, etc.) be furnished to the computer using 

 input forms discussed in Appendix C; output forms are also discussed in that appendix. These 

 data and the method for obtaining them are now discussed. In the next section of the text, 

 a "hand" calculation of the beam parameter for a sample ship section shows how these data 

 are used in making this calculation on the "digital" computer; this is true because a digital 

 computer operates on these data in a similar fashion. A comparison of the results of hand 

 and computer calculations is given. 



DATA 

 Geometry 



Consider the y—z coordinate system of a ship cross section shown in Figure 1, where 

 y is taken in the plane of symmetry for a symmetrical cross section. Otherwise the origin is 

 arbitrarily chosen. The geometry of every cross section obtained from ship plans is given by 

 the y—z coordinates of each node (Figure 1). 



A numerical assignment of nodes is made (1) at every point where there is a longitudinal 

 beam (2) at the junction of more than two plates* (e.g., junction of lower deck to hull), and 



'Plate" here designates segments of decks, hull, bulkhead, inner bottom, etc. 



