SOME SHIP DESIGN METHODS

This paper was presented on 9 Nov. 1976 in Glasgow at a joint meeting of the RINA and the IEES, and on 24 Nov. 1976 at an RINA meeting in London. The discussions following both presentations are included in the paper, together with a written Discussion and the Authors' replies to all three. Since the publication, in 1962, of the first-named Author's paper "Estimating Preliminary Dimensions in Ship Design", there have almost certainly been greater changes in ships than during any previous period of this length. The Authors (of Y-ARD Ltd) review these changes, examine the present relevance of the design data and methods presented in 1962, discuss developments in ship-design methods since that date, and consider the present state-of-the-art of preliminary design. The paper is arranged under the headings:--1) Introduction (Changes in Ships and the Shipping Fleet--The Changes in Machinery--Design Starting Point--Design Methods). 2) The Three Ship-Design Categories (The Deadweight Carrier--The Capacity Carrier--The Linear Dimension Ship--Solution of cubic Equations). 3) Dimensions, Displacement and Form (The Dimensional Relation-ships--The Beam/Length Relationship B=f(L)--Depth/Beam Relationship D=f(B)--The Draught/Depth Relationship T=f(D)--The Depth/Length Relationship D=f(L)--The Draught/Length Relationship T=f(L)--The Draught/Beam Relationship T=f(B)--Block Coefficient--Displacement--Appendages--Longitudinal Centre of Buoyancy). 4) Powering (Effective Horsepower PE--Adoption of ITTC Notation--Appendage Resistance--Correlation Factors--Quasi Propulsion Coefficient--Transmission Efficiency--Trail and Service Margins--Engine De-Rating). 5) Lightship Weight (Steelweight Ws--Scrap--Outfit Weight--Machinery Weight--Margin). See also MRIS Abstract 168254. Order from: BSRA as No. 47,080.