AN OR APPROACH TO THE PREPARATION OF LOADING PROCEDURES FOR ORE CARRIERS

Foreign ore exporting ports have been rapidly improved in response to the jumboizing of ore carriers and bulk carriers. However, there are difficulties in preparing the practical loading procedure due to the fact that the loading rate of ore tends to exceed the ship's ballast pump capacity. Also port administrator's requirements for more than 100,000 dwt carriers that, for example, (1) berthing trim be less than 8 ft., trim while loading be maintained less than 15 ft., (2) loader/hatch-top clearance and ship's bottom/sea bed clearance be no less than 3 ft., respectively, (3) ballasting and shifting be avoided, and de-ballasting alone be done, etc. A few OR techniques have been applied to prepared loading procedures and computer programs were coded in FORTRAN. First method is that of keeping the same lot size of cargo to be loaded at one time and ballast quantity retained in each tank to satisfy the constraints stated above were calculated for every possible loading stage. Then loading a sequence which gives the least loading time was chosen by using dynamic programming. As a second method, a heuristic approach is applied to find an early-optimal loading sequence in trial-and-error manner with the lot size of cargo maximized at each stage, consequently, the number of shifts of ore loader minimized, satisfying the constraints above. The comparison made between DP and heuristic approach shows that the latter method seems more powerful when the memorial space of a computer is limited. The computer programs constructed will help deck officers prepare a loading procedure for bulk carriers berthing with arbitrary draft condition and sailing with also arbitrary loaded condition using a shipboard digital computer.

  • Corporate Authors:

    Nautical Society of Japan

    2-1-6, Etchujima, Kotoku
    Tokyo,   Japan 
  • Authors:
    • Miki, T
  • Publication Date: 1973-7

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Filing Info

  • Accession Number: 00084898
  • Record Type: Publication
  • Source Agency: Nautical Society of Japan
  • Files: TRIS
  • Created Date: May 19 1975 12:00AM