A Containership Load Planning Heuristic for a Transtainer Basedcon- Tainer Port Redacted for Privacy Abstract Approved: Edward D
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AN ABSTRACT OF THE THESIS OF Gifford L. Martin, Jr. for the degree of Master of Science in Industrial Engineering presented on August 17, 1981. A Containership Load Planning Heuristic for a Transtainer BasedCon- tainer Port Redacted for Privacy Abstract Approved: Edward D. MeDdv:/ell A heuristic is developed to plan loads for containerized cargo ships. It is designed to serve a port which uses gantry cranes(trans- tainers) and trucks to handle containers. The model recognizes con- straints on ship stability, placing containers in a bay withthe proper length, placing refrigerated cargo nearelectrical outlets, limits on stack height in under deck bays, limits onstack weight in on deck bays, and the need for support under a container. Provisions are made for the operator to handle overstowage of cargo fordifferent ports, placement of hazardous cargo, and placementof oversize cargo. The model uses minimization of transtainer movement time andminimiza- tion of rehandles in the yard as an objective. The heuristic uses strategies for container placement similar to those usedin manual load planning. A test of two ships and four voyages at the Port of Portland produced feasible load plans for each voyage. Transtainer movement and rehandling time varied for the four voyages,but on aver- age the heuristic reduced a composite materialhandling measure by 4.8',L Time required for load planning should be substantiallyreduced using the heuristic. A Containership Load Planning Heuristic for a Transtainer Based Container Port by Gifford L. Martin, Jr. A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Master of Science Completed August 17, 1981 Commencement June 1982 APPROVED: Redacted for Privacy Professor of Industrial and General Engineering in Charge of Major Redacted for Privacy Head of Department,-Indust?Tal and Geral Engineering Redacted for Privacy Dean of Graduate Date thesis presented August 17, 1981 Typed by Mary Ann (Sadie) Airth for Gifford L. Martin, Jr. ACKNOWLEDGEMENTS I would like to express my thanks and deep appreciation to my major professor, Dr. Edward McDowell, for his support and encourage- ment during the writing of this thesis, and during my entire stay at Oregon State. I would also like to thank Dr. Tom West for ideas and suggestions included in this work, and Dr. Doug Cho for his explana- tions of some aspects of the load planning process. Nancy Young is deserving of my profound gratitude for her moral support over the last several months and for her aid to an author of little artistic talent in producing figures for this thesis. My sister, Janet Martin, also deserves credit for her assistance with the figures. My gratitude is also given to my typist, Sadie Airth, for translating my writing into presentable form and for helping me through the labyrinth of university rules on thesis formats. Finally,I would like to give my thanks to my parents, whose sup- port and confidence have been invaluable during my time in school. Table of Contents Page, I. INTRODUCTION 1 Background 1 Container Operations 5 Transtainer Yards 12 Terminal Six 15 Load Planning 17 II. PROBLEM ANALYSIS 20 Literature Review 20 Problem Formulation 24 Load Planning at Port of Portland 24 Statement of Objectives 29 Constraints in Load Planning 31 Simplified Model 35 III. ASSUMPTIONS AND GENERAL APPROACH 38 Assumptions 38 Alternatives for Solving 39 Heuristic Used 43 Guiding Principles 43 Cell Selection 43 Container Search 44 Checking Stability 53 Summary 55 IV. DATA STRUCTURES 57 Data Requirements 57 Ship Data 60 Cell Arrays 60 Bay List 64 Under Deck Bay List 66 On Deck Bay List 66 Stability Information 67 Container Data 71 Instructions from the Load Planner 82 Files 88 Pointers and Other Variables 90 Summary 92 Page V. PROGRAM EXPLANATION 95 Program Structure 95 Basic Structure 95 Subroutine Structure 99 Programming Language 102 Initialization of Variables (Block Data) 103 Input Subroutines 106 Bay and Port Selection (LOAD) 107 Cell Selection and Loading (FILLBAY) 110 Regular Container Search (REGLOAD,MOVED) 117 Strategy 117 Review of Yard Data 118 Overview 119 Preparation for Container Search 119 Search of Current Row 120 Search for the Correct Set 127 Search of a Section 130 Changing Sections (CHGSEC,INITSEC) 134 Special Weight Container Search (CRTWGT,LEVELS) . 133 Adjusting the Computer Load Plan (EXCHNG) 143 Calculating Stability (STABLE) 146 Results (OUTPUT, function subprograms) 148 VI. RESULTS 150 Introduction 150 Testing Procedure 150 Stability Results 153 Material Handling Results 157 Load Planner Productivity 169 Comments on Individual Voyages 171 VII. CONCLUSIONS 176 General Conclusions 176 Evaluation of Strategies Used 177 Suggestions for Further Research 181 BIBLIOGRAPHY 183 APPENDICES A. Flow Charts 185 B. Variable Definitions 210 C. Major Lists Used to Organize Data 220 D. File Structures 221 Page APPENDICES E. Program Listing ?24 F. Sample Run 300 G. Variables Initialized in BLOCK DATA 332 LIST OF FIGURES Figure Paae 1-1 Terminology of container locations aboard ship. 7 1-2 Top view of ship stack and cell guides 8 1-3 Material handling equipment 9 1-4 Top view of yard layout for straddle carriers . 10 1-5 Top view of gantry crane yard 11 1-6 Terminology of container positions in a yard section 14 1-7 Layout of Terminal 6 16 2-1 General plan of Alaska Maru with cells assigned to ports 26 2-2 Work sequence sheet for one crane 27 2-3 One page of the stowage plan for the Alaska Maru's Voyage 89 28 2-4 Under deck bay with too many high cubes in one stack 33 3-1 Loading sequences and weight targets for cells with different destinations in the same bay . 45 3-2 Order of preference for containers within a row based on position alone 49 3-3 Order of row selection during container search for regular and critical weight search procedures 50 4-1 Typical on deck and under deck ship bays 62 4-2 Bay list entries for a hypothetical containership . 65 4-3 Relationship between set and row lists 75 4-4 Relationship between set, row, and container lists. 76 Figure Page 4-5 Set and row list entries for a row with containers for two ports 79 4-6 Order of container list entries for a row with containers for a single port 80 4-7 Sample tier list entries for a bay-port with a single block of cells 84 4-8 Sample tier list entries for a bay-port with two blocks of cells 84 5-1 Basic program functions 96 5-2 Basic ship loading activities 97 5-3 Feedback loop for load plan modification 98 5-4 Subroutines used to read data 99 5-5 Subroutine structure for load planning 100 5-6 Subroutine structure for modifications, stability, calculations and results 102 5-7 Relation between bay and cell array before loading. 105 5-8 Flow of activities in LOAD 109 5-9 Flow of activities in FILLBAY 111 5-10 Selection of container search subroutine 113 5-11 Flow of activities in REGLOAD 121 5-12 Order of search of containers in hypothetical row . 123 5-13 Variety of ports in yard stacks 124 5-14 Set list and pointer 135 5-15 Flow of activities for CHGSEC 137 5-16 Flow of activities for CRTWGT 141 5-17 Menu printed by EXCHNG 145 5-18 Explanation of format used to print cell data . 149 Figure Page 6-1 Adjacent vs. non-adjacent section changes 158 6-2 Plot of distance vs. time for observations taken at PoP 159 6-3 Histogram of total times for voyages 165 6-4 Histogram of total times for the material handling factors 168 6-5 Container locations for Japan Apollo V10 172 6-6 Container locations for a single port-length . 173 LIST OF TABLES Table Page IV-1 Data Structures Needed for Load Planning 58 IV-2 Components of Ship Stability 68 IV-3 Complete Bay Lists 72 IV-4 Current Status Variables 91 IV-5 Variables for Maximum Size and Number of Entries in Lists 92 IV-6 Statistical Variables 93 V-1 Basic Weight Ranges for Container Lengths and Weight Classes 106 V-2 Values Entered by Load Planner in STABLE 147 VI-1 General Stability Ranges 153 VI-2 Stability Results for Test Voyages 154 VI-3 Parameters Used in Test Voyages 155 VI-4 Row and Container Ranges for Japan Apollo V10 156 VI-5 Number of Containers in Each Weight Class for Four Voyages 156 VI-6 Times Used for Material Handling Factors 159 VI-7 Material Handling Results by Voyage 164 VI-8 Material Handling Results by Material Handling Factors 167 A CONTAINERSHIP LOAD PLANNING HEURISTIC FOR A TRANSTAINER BASED CONTAINER PORT CHAPTER I. INTRODUCTION Background Throughout history shipping has been a key element in interna- tional trade. Raw materials must be transferred from areas where they are plentiful to areas where they can beprocessed. Finished goods must be delivered to areas where they will be used.Where water routes are available, ships have often been the cheapest means of transportation. This is as true today as it was in ancient times when the Phoenicians plied the Mediterranean. Today shipping is a vital part of the international economy. In 1980 shipping accounted for 79.5% by,dollars and 99.8% by tonnage of U.S. overseas trade (Highlights of U.S. Export and Import Trade, 1981). An efficient shipping industry is therefore important to this country's economic well-being. The economics of shipping usually favor large, fast vessels over their smaller or slower counterparts. This fact, coupled with tech- nological advances, has caused a rapid increase in both the size and speed of vessels built since World War II.