A general discussion on trends in the design and operating costs of "standard" cargo-ships since the early 1960s leads to the Author's view that these ships should be redesigned to take the following factors into account: (a) the hull should be suitable for a large range of propulsion-powers, since many of these ships are now used as "semi-liners" and different owners may require different speeds for their particular operations, and (b) the high cost of fuel at present, and the probability of even higher prices in the future, should be given consideration. Although there have been various suggestions on the design of the hull form for these standard ships, it would appear that no rigorously systematic study has been made; the objectives of the present study are therefore (a) to show that it is possible to design ships with hull proportions and fineness that enable substantial economy to be achieved through a lower total operating cost, and (b)to establish a general methodology for such studies that is applicable to all cases including non-standard types of ship. For his study, the Author makes use of two computer programs, one "technical" and the other for economic evaluation. For the technical program, a basic ship is selected and all possible variants resulting from different values of length, breadth, depth, draught, and block coefficient are considered. The economic program subjects these variants to a total-operating-cost analysis which permits the optimum solutions to be selected. The two programs are applied to a 15,500-dwt and a 20,500-dwt basic ship-design, each representative of present-day standard cargo-ships; the larger vessel has a breadth of 22.86 m (the St Lawrence Seaway limit). The results are presented and discussed in detail. Several conclusions are drawn on the operating economics of standard cargo-ships in relation to hull proportions, hull fineness, and current fuel prices. It is found inter alia that substantial savings in operating costs can be obtained, without much difference in the initial costs of the ship, by employing block coefficients of about 0.7 (instead of about 0.75, usual in these ships) in combination with slightly increased draught and, depending on whether the breadth can be increased, a change in length, as compared with present conventional designs. Order from BSRA as No 49,391.

  • Corporate Authors:

    Asociacion de Ingenieros Navales

    Apdo Correos 457
    Madrid,   Spain 
  • Authors:
    • Mandelli, A
  • Publication Date: 1978-6


  • Spanish

Media Info

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Filing Info

  • Accession Number: 00188717
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Feb 27 1979 12:00AM