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APPENDIX A ABSTRACTS OF PERTINENT ARTICLES AND REPORTS Listing Anonymous (1971), "Squat," Comm~ndant's International Technical Series, Vol. I, Report No. USCG-CITS-71-1-1 (Washington, D.C.: U.S. Coast Guard). Anonymous (1979), "Automatic Survey Techniques on the Waterways and Approaches to Rotterd~m" (Netherlands: Rijkswaterstaat, Direktie Benedenrivieren, Meetdienst). Anonymous (1981), "A Report on Bed Density Measurements and Echo Sounding at Humber Ports," Report No. R. 286 (United Kingdom: British Transport Docks Board, Research Station). Anonymous (N.D.), "Density Measurements In Situ," (Netherlands: Public Works Department, Lower Reaches Directorate, Surveying Division, Research Section ~ . Anonymous (1981), "New Non-Linear Sub-Bottom Profiler System, n International Dredging & Port Construction, April 1981, pp. 29-30. Berriman, J. W. and J. B. Herbich (1977), "Major Port Improvement Alternatives for the Texas Coast," COE Report No. 197, TAMU-SG-77-205 (College Station, Tex.: Texas Ash University). Bijker, E. W. (1978), "Science and Design of Navigation Trenches and Offshore Trenches, " Proc. 8th World Dredging Conf ., pp. 69-76. Bijker, E. W. (1980 I, "Sedimentation in Channels and Trenches, " Proc. 17th Coastal Ena. Conf ., ilol . II, OD . 1708 - 1718. . ~ . Blaauw, H. G., J. W. Koeman,and J. Strating (1981), "Nautical Contributions to an Integration Port Design," Publication No. 251 (Netherlands: Delft Hydraulics Laboratory). Bos, H. (1979), "Marketing Research and Business Economics," Land and Water International, pp. 20-22 Eden, E. W. (1971), "Vessel Controllability in Restricted Waters," J. Waterways, Harbors and Coastal Eng., Proc. ASCE, 97(WW3~: 475~-490. A-1
A-2 Gates, E. T., and J. B. Herbich (1977a), "Mathematical Models for the Design, Operation and Economic Analysis of Deep-Draft Navigation Channels," Proc. 24th International Nav. Cong., PIANC, Leningrad, U.S.S.R., pp. 175-181. Gates, E. T., and J. B. Herbich (1977b), "Mathematical Model to Predict the Behavior of Deep-Draft Vessels in Restricted Waterways," COE Report No. 200 (College Station, Tex.: Texas A&M University). Gates, E. T., and J. B. Herbich (1978), "A Mathematical Model for the Review or Design of Deep-Draft Navigation Channels with Respect to Vessel Drift and Rudder Angles," Proc. Symp. on Aspects of Navigability, Delft, Netherlands, April. Hellema, J. A. (1979), "Density Measurements In Situ" (Netherlands: Public Works Department, Lower Reaches Directorate, Measuring Division, Research Section). Herbich, J. B., W. R. Murden, and C. C. Cable (1981), "Factors in the Determination of a Cost-Effective Dredging Cycle," Proc. XXV Int. Nav. Cong., Inland and Maritime Waterways and Ports, PIANC, Section II, Vol. 2, Edinburgh, Scotland, May 10-16. Huval, C. J. (1978), "Mathematical Models for Navigation Cnannel Design," 26th Proc., Annual ASCE Hydraulic Civ. Spec. Conf., Verification of Math. and Phys. Models in Hydraulic Eng., University of Maryland, August 9-11, pp. 273-279. Iijima, Y., and K. Honda (1973), 'iChannel Width of Harbor Entrance, · J. Naut. Soc e Japan, _: 91-10 3 e International Association of Ports and Harbors (1981), "Special Care Measures for Safe Disposal of Polluted Dredged Material in the Marine Environment,'' Submitted to the Ad Hoc Scientific Group on Dumping--Sth Meeting, Halifax, Canada, May 4-8. Kirby, R., W. R. Parker, and W. H. A. van oostrum (1980), "Definition of the Seabed in Navigation Routes through Mud Areas," International Hydrographics Rev., Monaco, LVII(11: 107-117, (Also First International Hydrographic Technical Conference, Ottawa, My I'9~)''.'' Kondstaal, R., and J. van der Weide (1981), "Systems Approach in Integrated Harbor Planning," Publication No. 250 (Netherlands: Delft Hydraulics Laboratory), Presented at the Seatech III Conference in Asian Ports Development and Dredging, Singapore, March. Kray, C. J. (1973), "Design of Ship Channels and Maneuvering Areas," J. Waterways, Harbors and Coastal Eng., Proc. ASCE, 99(WW1~: 89-~.
A-3 McDonald, R. M. (1977), "Development of the Ship Channel between Montreal and Deep Sea," Marine Tech., 14: L92-197. , Mikkelsen, L., P. Mortensen, and T. Sorensen (1980), "Sedimentation in Dredged Navigation Channels," Proc. 17th Coastal Eng. Conf., Vol. II, pp. 1719-1734. Minorsky, V. U. ~ 1977 ), "Grounding Probability Studies, " final Report on Task IV, Feb. 76 - Jan. 77, prepared for U.S. Maritime Administration by George C. Sharp, Inc., New York. Muir , William C., G . D . Pence , and J . R. Pomponio ~ 1981 ), "Deepening the Hampton Roads--The EIS Process, " Proc . 14th Annual Dredging Seminar College Station, Tex. : Texas A&M University). Nederlof, L. (1979), '"Sailing Through Water Rich in Silt: A Vessel Behaves Differently but Remains Manageable," Rotterdam Europoort Delta, pp. 19-22. Nederlof, L., and G. van Bochove (1981), "Maneuvering Behavior of Ships in Muddy Canals and Harbors," The Dock and Harbor Authority, Netherlands, Vol. LXII, No. 726 (May), pp. 2-6. Ottevanger, G. (1979), "Dredging Operations in the Approaches to Rotterdam," Land and Water International, pp. 27-32. . Trawle, M. J. (1981a), "Prediction of Shoaling Rates for Deepened Estuarine Navigation Channels," Proc . 14th Annual Dredging Seminar ~ College Station , Tex .: Texas A&M University ~ . Trawle , M . J . ~ 1981b ), Ef f ects of Depth on Dredging Frequency : Methods of Estuarine Shoaling Analysis, Technical Report H-78-S ~ Vicksburg, Miss .: U. S . Army Engineer Waterways Experiment Station ~ . Trawle, M. J . and J . B. Herbich ( 1980 ), "Prediction of Shoaling Rates in Offshore Navigation Channels," Center for Dredging Studies, Department of Civil Engineering, Report No. 232 (College Station, Tex.: Texas A&M Uniters ity ~ . Troesch, A. W., and S. Cohen ~ 1980 ), "Relationship of Underkeel Clearance and Vessel Speed to Grounding, " Report No. 017999, Ship Hydrodynamics Lab, University of Michigan. Turner, H. D. ~ 1978 ), "Physical Model Study for Improved Navigation Channel Design, " 26th Proc ., Annual ASCE Hydraulic Div. Spec. Conf.: Verification of Math. and Phys. Models in Hydraulic Eng., University of Maryland, August 9-11, pp. 265-272 . van de Ridder ~ 1979 ), "=tterdam and the Harbor Silt, " Land and Water International, pp . 23-26 .
A-4 van Donselaar, H., et al . ~ 1981 ), "The Maritime Impact of Liquid Energy Gases--the Planning and Operational Aspects' " Maritime Ports and Seaways, Vol. I, Permanent International Association of Navigation Congresses, XXV, Sec. II. van Oostn~m, W. H. A. ~ 1979a ), "Maintenance Dredging in Soft-Bedded Navigation, " Control Dredging Association (CDEA) Conf ., Netherlands . van Oostrum, W. H. A. (1979b), International, pp . 17-19 . "MKO Project," Land and Water van Oostrum, W. H. A. ( 1979c ), "Operations Research in Dredging, " Terra et Agua, 18: 2-15. van Oostrum, W. H. A., W. R. Parker, and R. Kirby { 1980 ), "Maintenance Dredging in Fluid Ad Areas, " Third Int. Symp. Dredging Tech., Bordeaux, France, pp . 177-190 . van Oostrum, W. H. A., et al . ~ 1981 ), "Dutch Ef forts for Optimization of Marine Dredging, " Proc. XXV Int. Nav. Cong., Inland and Maritime Waterways and Ports, PIANC, Section II, Vol . 2, Edinburgh, Scotland, May 10-16 e Wang, S . ( 1980 ), "Full-Scale Measurements and Statistical Analyses of Ship Motions in a Navigational Channel, n Marine Tech., 17: 351-370 . Waugh, Richard G., Jr. ( 1971 ), "Water Depths Required f or Ship Navigation, " J. Waterways, Harbors and Coastal Eng., Proc. ASCE, 97(WW3~: 455-473. Wicker, C. F. (1971), "Economic Channels and Maneuvering Areas for Ships," J. Waterways, Harbors and Coastal Eng., Proc. ASCE, . . 97(WW3): 443-454. Young, R. W. ~ 1978 ), "Or the Interactions cuff Slender Ships in Shallow Water, " J. Fluid Mech., 85 : 143-lS9 . - Zahn, A. S. (1977), "Grounding Characteristics and Effects," Final Report on Task 5, Oct . 76 - Jan. 77, Prepared for U.S. Maritime Administration by George C. Sharp, Inc ., New York .
A-5 Anonymous (1971), "Squat, " Commandant's International Technical Series, Sol . I , Report No. USCG-CITS-71-1-1 ( Washington, D.C .: U. S. Coast Guard ~ . Author's Abstract - The report contains four papers on squat in shallow water as follows: from the Federal Republic of Germany, a paper on the results of model tests of a 700,000 DWT tanker; from France, a paper on the results of model tests of a 500,000 DWT twin-screw tanker; from Poland, a paper on the results of model tests of two ships with large block coefficients, one with bulbous bowl and from the United Kingdom, a paper on the results of model tests of two ships, one in the naked hull condition, and the other equipped with self -propulsion gear, twin screws, twin rudders, and bulbous bow. Anonymous (1979), "Automatic Survey Techniques on the Waterways and Approaches to Rotterdam" (Netherlands: Rijkswaterstaat, Direkt~e Benedenrivieren, Meetdienst ~ . Abstract Automation in survey and maintenance dredging activities was introduced at the end of 1974 to supply depth information on the waterways and approaches to Rotterdam. This report gives a brief description of the 'tWaterweg" system which has been installed on trailing dredgers and survey vessels. The shore-based processing system is described, as well as the incorporation of radioactive density meters into the system. Anonymous (1981), "A Report on Bed Density Measurements and Echo Sounding at Hummer Ports," Report No. R. 286 (United Kingdom: British Transport Docks Board, Research Station). Author's Abstract Following the introduction of echo sounders to assist with the production of hydrographic sounding charts, depths--particularly in soft bed areas--have become more variable and generally less deep. This report describes a series of field measurements which were best -¢ determine:Lhe variatio~-=f~dens~ty worth depths alto. establish the density horizon that echo sounders record as "the bed." Throughout the period of study, developments have been made both with the instrumentation (particularly that used to measure the density of the bed) and with operational techniques. AS a consequence greater attention has been given to the more recent observations. In soft bed areas the echo sounder records the bed at varying density horizons. Tome, location, density and acoustic gradients within the bed are some of the factors which affect the measured depth.
A-6 The study concludes that in soft bed areas the depth recorded by echo sounders does not correspond to any specific horizon. It can be signif icantly above or below the water column/bed interface . Consequently, it is recommended that in these areas conventional echo sounding is supplemented by routine densimeter observations. Anonymous (N.D.), "Dei~si.ty Measurements In S'tu," (Netherlands: Public Works Department, Lower Reaches Directorate, Surveying Division, Research Section ~ . See also: Hellema, J. A. (1981), "Silt Density Measurement," fine Dock and Harbour Authority, January 1981, pp . 282-284 . Abstract . Excessive siltation takes place In Europoort, and the very thin silt is inefficient to dredge. After extensive tests, the nautical bottom was defined as the depth at which a density of 1200 kg/m3 was measured. Since a normal echo sounder cannot detect this nautical depth, because of the loss of signal in the silt, a radioactive density probe has been developed for this purpose. The probe is lowered into the s, it, and the amount of radiation reflected by the silt def ines the measured density. This report describes the practical tests of radioactive density measurements since the end of 1973, together with the findings during the ensuing operational period. As these point-measurements are time-consun~ng' a special subbottom profiler with parametric transmitter has been developed to provide continuously available subbottom information. This system is believed to be the f irst of its kind in Western Europe. Anonymous ( 1981 ), "New Non-Linear Sub-Bottom Profiler System, " International Dredge ng & Port Construction, April 1981, pp. 2tt-30 . Author's Abstract This brief article presents the technical details of a non-linear sub-bottom profiler to be developed by Ulvertech Ltd. of UIverston, Cumbria, for deployment in and around both Europoort and Rotterd~m. The profiler will be housed in a gyro-stabilized platform so that will not be affected by the roll and pitch motion of the survey craft. The system will provide a very acurate coercer -the seabed and show the dif f Brent dens ity layers to a depth of about 2 0 m below the seabed. Details of a dual mechanical scanning sonar system and sonar video system developed by Ulvertech are a' so presented in the article . it Berriman, J . W., and J. B . Herbich ~ 1977 ), "Major Port Improvement Alternatives for the Texas Coast, " COE Report No. 197, TAlIIJ-SG-77-205 (College Station, Tex.: Texas A&61 University). a
A-7 Abstract With the advent in recent years of very large crude carriers ( VLCC ) and ultralarge crude carriers (UICC), the United States has fallen behind many other maritime countries in providing suitable docking facilities. The shortfall in port facilities capable of handling the deep~draft vessels, coupled with rapidly growing volume of imports and exports of bulk commodities, has resulted in a critical need for improved port facilities in this country. The lack of port facilities capable of handling VLCCs and ULCCs, coupled with a rapidly growing volume of imports and exports of bulk commodities, and projected growth in oil importation and refining petrels, make it imperative that port facilities be further improved along the Texas coast. The onshore deepwater port has the advantage of being able to accommodate the larger carriers of bulk commodities as well as large tankers which transport petroleum products. The port improvements for the Texas coast are deemed to be necessary to provide modern and efficient port facilities to shippers and ensure continued economic well-being for the regions served by these ports. Ship channel design criteria are discussed in terms of mi nimbi width and depth requirements for various size vessels. A portion of the design work contained ~ n this paper was checked using a mathematical model developed by Mr. Edward T. Gates of the U.S. Army Corps of Engineers and a graduate student at Texas A&M University. It is recommended that this mathematical model be utilized extensively in any future work dealing with channel design. The following channel design criteria are necessary to provide for the safe navigation of VLCCs and ULCCs: 1. Channel Width Maneuvering Lane (A) = 2 . 0 x Beam + L sin 10°, where L sin 10° applies to channels with strong yawing forces. Bank Clearance Tane (B) = 1.5 x Beam Ship Clearance Lane (C) = 1.0 x Beam One-Way Traffic Width = A +2B Two-Way Traffic Width = 2A + 2B + C cquann~I D~l,j. Channel Depth in Inner Channel = f (loaded draft, squat, and minim keel clearance ~ Channel Depth in Outer Channel = f (loaded draft, effect of pitch and roll, and minimum Keel clearance), where effect of roll and pitch = L/2 sin 1°.
A-8 Imprc~ed channel designs are presented for the ports of Port Arthur, Galveston, Freeport, and Corpus Christi. Bi jker, E. W. (1978), "Science and Design of Navigation Trenches and Offshore Trenches, " Proc. 8th World Dredging Conf ., pp. 69-76. Author' s Abstract The general requirements of shipping lanes are that they guarantee a safe passage of the ships with regard to navigation in general, and width and depth in particular. The impact of science as discussed in this paper means that under more or less normal conditions, empirical knowledge may be suf f icient; for extraordinary new situations, however, a basic knowledge of the physical phenomena determining the situation will be required. This implies that theories should be available or developed to elaborate wave and current data in order to predict the behavior of the channel and of the ships in the channel. Bijker, E. W. (1980) r "Sedimentation in Channels and Trenches," Proc. 17th Coastal Eng. Conf., Vol. II, pp. 1708-1718. - Abstract In this paper, the siltation in approach channels and trenches due to crosscurrents and waves in discussed. When the current crosses the channel obliquely rather than at a right angle, a greater distance over which the water f lows over ache greater depth is introduced . Deviations in the flow pattern due to the channel are neglected. However, when the flow pattern is known, either from measurements in nature or in the model, this effect can easily be introduced. The influence of the waves is introduced through an increased bed shear and subsequently higher diffusion coefficient. Although computer programs are available to calculate the siltation under the above described circumstances, the paper presents a relatively simple method which permits a quick estimate of the siltation to be expected without the use of a big computer. This method could be useful for a first appraisal for the various solutions, by the engineer in the field. Blaauw, H. G., J. W. Koeman, and J. Strating ~1981 ) , "Nautical Contributions to an Integration Port Design, " Publication No. 251 (Netherlands: Delft Hydraulics Laboratory ~ . Abstract This paper presents a harbor design strategy in which the nautical aspects are treated as an integral part. A harbor is designed to ensure the safe and efficient transport of goods, and these goals are, to a large extent, determined by the behavior of ships. The paper shows that different nautical research tools should be used at the various design phases. In the initial phase, several design
~ - 9 alternatives are produced using rules of thumb, engineering experience, or mathematical models. An initial master plan is selected, and in the final stage, advanced hydraulic models and maneuvering simulators may be used to optimize the initial master plan. The nautical research tools are described in detail, and the setup is illustrated with the results of research programs and recent case studies. Bos, H. (1979), "Marketing Research and Business Economics," Land and Water International, pp. 20-22. - Abstract The Dutch dredging market is divided into three sectors: (1) the sand sector (mining of sand, clay, gravel, etc.), (2) the maintenance sector, and (3) the capital sector (new works). The price development for trailing-suction dredging work in the Netherlands indicates that the average level of prices is continually rising, while the mutual differences between the observed market prices have increased. The effect of recent changes in the dredging market on the relationship between contractors and principals in various sectors of the market is discussed. Methods for minimizing the cost of maintenance dredging for the principal by reducing the quantity to be dredged and the price per unit of spoil are suggested. Eden, E. W. ( 1971 ), "Vessel Controllability in Restricted Waters, " J . waterways ~ Harbors and Coastal Ens ., Proc . ASCE , ~ 7 ( WW3 ): 475-490. Abstract . A discussion of vessel controllability in restricted waters is presented, and the factors inf luencina controllability are considered . . . ~ . . _ in retail . Tne ma Coon or a vessel generates pressures, currents, and waves which, after impingement upon restricting boundaries, will create secondary reactions. Those forces vary with the clearance between the vessel and fixed boundaries and the speed of and distance to other vessels, if any. The controllability of the vessel depends upon the rudder power, the reaction of the pilot, and the speed with which changes in vessel speed. and. heading can be madly The hydrodynamic characteristics of vessel motion through the water and the effects of rigid boundaries and passing ships are explained. The action of a single propeller or twin propellers is another factor which affects the shape and magnitude of pressure and velocity f gelds. Methods of evaluating the controllability of a vessel are described. Standard maneuvers such as the zig zag, spiral, or sine test are used to determine the reaction of the vessel in full-scale, deepwater trials or in hydraulic model tests in the laboratory. Another index used by naval architects to define controllability is the tu~ning.circle at full ahead speed with a 35° starboard rudde '..
A10 The stopping distance is also an important element of controllability. Experimental data index cate that at least four factors important in the controllability of any vessel vary with the re lative channel dimens ions . These factors are (1) s~nkage or squat, (2) lateral forces and turning moments, (3) directional stability, and (4) resistance, or drag. The research needs are briefly reviewed and a program to reduce uncertainties and improve theoretical appraisals of vessel controllability under given conditions is described. Gates, E. T., and J. B. Herb~ch (1977a), "Mathematical Models for the Design ~ Operation and Economic Analysis of Deep-Draf t Navigation Channels, " Proc. 24th International Nav. Cong., PIANC, Leningrad, U. S. S . R., pp 17S-181 . Abstract Engineers generally determine the dimensions of a navigation channel by design policy and by use of standard ratios of proportions of the selected design vessel. Because of the great changes in relative dimensions of the world's marine fleets, these techniques should no longer be universally applied. This criterion--ratio approach to design--also does not take into consideration the individual characteristics (prevailing winds and currents) of each separate channel location. A channel design model and a channel operations model (under development ~ are described in this paper. These models are modular in structure and include theory limitation indicators. The channel design model determines the design vessel's reaction to the effects of squat, changes in water salinity, boundary layers due to vessel motion, current, wind, changes in neutral s leering line due to asymmetry in the channel cross -section, bank suction, and other phenomena. The squat modu ~ ~ computes the increase in vessel draft due to brackish water, then computes the squat for the primary ( design ) vessel alone and when ~ n a massing or overtaking condition with a _ _ _ . ~ . . . ~ _. . secondary vessel for each speed in a designated range. The bank suction module computes the lateral forces and turning moments due to the bank suction phenomenon. The neutral steering line module computes the distance between the neutral steering line and the channel centerline for a given cross-section and then adds this distance algebraically to the given ship off-centerline distance. This new distance is used by the bank suction module in computing lateral forces and turning moments. The vessel attitude module determines the magnitude of the drift angle and rudder angle required to neutralize the lateral forces and turning moments caused by the effects of bank suction, crosswinds, and lateral current components. The ship-generated waves module calculates the magnitude of the ship-generated wave at the vessel and at each cusp point as the wave propagates out from the vessel sailing line. The stopping distance module computes the astern thrust per ton displacement ratio required to stop a vessel in a given required distance.
A-11 The channel operations model mathematically simulates the movement of vessels and barge trains in and out of a specified port. This model accumulates and reports operational, safety, and cost data for delays due to passing traffic including barges, one-way traffic, passing fixed objects such as bridge piers, accidents, insufficient draft due to wind and tides, bad weather, unavailable dock facilities, and traffic saturation. The channel design model is being used by the Galveston District; U.S. Army Corps of Engineers; the Galveston, Texas, City Port Safety Advisory Council; and the U.S. Coast Guard, and the results to date have been good. The channel operations model is expected to be operational in the near future. Gates, E. T., and J. B. Herbich (1977b), "Mathematical Model to the Behavior of Deep-Draft Vessels in Restricted Waterwa~rs Report No. 200 College Station, Tex.: Texas A&M University . Predict ." COE Author' s Abstract Presently deep-draft navigation channel analysis, design and review is based on empirically derived ratios of the design ~ressel's dimensions. Because of radical changes in vessel operation purposes and characteristics, these ratios can no longer be safely or economically applied. The mathematical model and related theory described in this document provide the engineer with a comprehensive tool in the design and review of deep-draft navigation channels. Through its use he will be able to predict values of squat, bank suction forces and moments, equilibrium drif t and rudder angles, and heights of ship~generated wares for varied channel configurations, ship positions and ship velocities. Through the determination of channel section confi guration sensitivity, an optimal des' gn both operationally and economically can be achieved. Gates, E. T., and J. B. Herbich (1978), "A Mathematical Model for the Review or Design of Deep-Draft Navigation Channels with Respect to Vessel Drift and Rudder Angles," Proc. Sump. on Aspects of Navigability, Delft, Netherlands, April. Author's Abstract A comprehensive mathematical model has been developed for the design and review of deep-draft navigation channels. Input to the model consists of the channel configuration, the design vessel dimensions and environmental considerations such as winds and currents. The output consists of squat values, neutral steering line variations, bank suction forces and turning moments, drift and rudder angles required to overcome the various forces and turning moments , ship-generated wave heights and stopping distances , all for varying speeds and varying distances from the centerline of the channel.
A-12 This paper deals predominantly with the theory involved with the variation of the neutral steering line caused by the asymmetry of the channel cross section and with the determination of bank suction forces and turning moments and the required vessel drift and rudder angles to overcome these forces and moments. Lateral currents and wind can also be considered. The Houston Ship Channel has been used as a prime example of the model' s application. The deviation of the neutral steering line from the centerline of the channel in passing or overtaking is traced f or the Houston Ship Channel. Design procedures are presented to demonstrate what changes can be made to the channel cross-sect~on to shift the neutral steering line back toward the centerline of the channel, thereby reducing any excessive drift and rudder angles to allowable values. Hellema, J. A. (1979~, "Density Measurements in Situ" (Netherlands: Public Works Department, Lower Reaches Directorate, Measuring Division, Research Sections. Abstract . . The rapid increase in the draft of ships was one of the factors that prompted the construction of the Europoort harbor area and the Maas Flats. The orig' nal aim of the design was 57 ft. but at the opening of the permanent entrance in June ~ 971, Europoort was capable of handling ships of 65 ft draft. The everincreasing scale of the ships led to Europoort' s access channels and harbor basins being further deepened so that at the end of 1974, ships of 68 f t draf t could be accommodated . As the harbor depth increased, a new problem emerged: each year millions of cubic meters of silt had to be dredged to maintain the guaranteed depth of Amsterdam Ordnance Dat~n--2 2 . 5 m in Europoort . The cost involved led the National Public Works Department and the municipality of Rotterdam to initiate a joint research project at the end of 1973 entitled "Minimizing the Costs of Maintenance Dredging Work." The working party on "Silt Soundings and Density Measurements" recommended the radioactive density meter of the Atomic Energy Research Establishment ~ AERE ~ at Harwell, England, as a means of measuring the silt density for the study. This report describes the development and methodo ~ ogy of the density measurz-rrg system. Herbich , J . B., W. R. burden, and C . C . Cable ~ 1981 ), " Factors in the Determination of a Cost-Effective Dred<~inc~ Cycle, " Proc . XXV Int. Nav. Cong., Inland and Maritime Waterways and Ports, PIANC, Section II, Vol. 2, Edinburgh, Scotland, May 10-16. Abstract - In dete`~uining a cost-ef fective dredg~ng cycle, one should consider and include the cliff Brent stages involved:
A-13 1. The definition of requirements for the navigation channel characteristics and for the method of disposal of the dredged material. 2. The design and specifications, which includes the geotechnical site investigation, project design elements, optimization of the dredging system, and the method for measuring progress and for determining satisfactory completion of a project. 3. The execution of the work in accordance with the environmental laws of the United States. 4. The design and construction of dredges in the United States. The report discusses the research needed to improve the efficiency of the dredging cycle, save fuel , and reduce dredging costs. Huval , C . J . ~ 1978 ), "Mathematical Models f or Navigation Channel Design, " 26th Proc., Annual ASCE Hydraulic Civ. Spec. Conf., Verification of Math. and Phys. Models i n Hydraulic Eng., University of Maryland, August 9-11, pp. 273-279. Abstract The U.S. Army Engineer Waterways Experiment Station (WES) has undertaken a study to determine the minimum dimensions of deep-draft navigation channels compatible with the assurance of safe operating conditions. The factors influencing ship control and the design of navigation channels are discussed, with emphasis on the piloting and navigation aspects of the control system. Some of the critical maneuvers during the port approach and exit phases are also described. The advantages and disadvantages of alternative research techniques are evaluated and compared. The main advantage of physical models is the ability to observe the channels and the ship maneuvers' while the disadvantages are the model-to-ship resistance differences and the time-scale distortion due to Froude scaling between velocity and distance ratios. The model piloting behavior is dependent on the time scale, and the effects of time-scale distortion on scale model test results are not presently known. anathema tical models use the equations of ship motion together with captive model test data. A complete mathematical model with complex bank suction ef f eats requires the detailed specif ication of many hydrodynamic coef f icients and involves many towing tank test conditions. If hydroclyn~ c data are available, however, the ease and speed of solution make this technique attractive f or an exploratory study of navi gation aid aspects of Piloting ships into channels. Ship simulators have been developed for necessary for ship study of channel design. _ ~ motion calculations and to control simulated ship bridge nautical equipment and the image of the proj ection system. The use of A dedicated computer is
A-14 mathematical models at WES is briefly discussed, and the development of a ship research simulator is considered. The three research methodologies should be used j ointly in a complementary fashion. Iijima, Y., and K. Honda (1973), "Channel Width of Harbor Entrance," J. Naut. Soc. Japan, _: 91-103. Author's Abstract The design of harbor entrances must be dictated by the size and maneuverability of the largest vessel anticipated to enter the harbor and also the local factors, but it does not seem that the design of existing harbors considers very many of the above factors. This paper describes how a criterion of harbor channel width is expressed as a numerical formula based on the above factors. The total width of channel is divided into three widths whose clearances are based upon a study of the Panama Canal, that is, (a) width of maneuvering lane, (b) width of the bank clearance lane, and (c) width of the shin clearance lane. A computer program called TRANSAP-LNG is used for system design and economic evaluation of LNG transportation systems. The system model includes all the stages related to LNG transportation, such as gas well=, gas pipelines, liquefaction stations, LNG tankers and gasification stations. Since these sub-systems, either single or multiple, are linked together as a total system, optimization of the total system of multiple projects can be made as well as optimization at lower system levels. Particularly, an optimized LNG tanker can be designed in view of optimization of the total transportation project. ~ , _~ International Association of Ports and Harbors (1981), "Special Care Measures for Safe Disposal of Polluted Dredged Material in the Marine Environment," Submitted to the Ad Hoc Scientific Group on Dumping--5th Meeting, Halifax, Canada, May 4-8. Abstract The need for dredging of ports and harbors both for enlargement and for maintenance of existing channels is expected to increase in the 1980s and beyond. Ways must be found to permit ports and harbors to continue the dredging of new and existing waterways to assist in achieving safe passage of vessels of commerce. A certain percentage of this dredged material, particularly that derived from maintenance dredging, can be expected to be polluted with Annex I substances, which must be disposed in such manner as to cause the receiving environment as little degradation as is reasonably possible. Public and economic pressures against use of some present-day types of land environments are increasing the difficulty of finding and using disposal sites on the land that can be considered safe and within reasonable distances from ports and harbors. Examination of the marine environment reveals that it has a high potential for
A-15 assimilating dredged material without creating undue environmental risk. This paper examines the problem and delineates possible solutions. It is concluded that if "special care" measures are used in disposal and in campsite selection, the disposal into the marine environment of dredged material containing Annex I substances would in many cases present no greater risk of environmental nanm tnan the disposal of Annex II substances. . . . . . . Kirby, R., W. R. Parker, and W. H. A. van oostrum (1980), "Definition of the Seabed in Navigation Routes through Mud Areas," International Hydrographies Rev., Monaco, LVII (1~: 107-117 (Also First International Hydrographic Technical Conference, Ottawa, May 1979~. Author's Abstract Over most types of seabed the interface between the seabed sediment and the overlying sea water column is sharp and clearly identified by ~ -- ~ large mobile survey echo sounders. However, in areas with a population of cohesive sediment (mud), dense layers of- suspended sediment occur which are intermediate in character between muddy seawater and the settled mud of the bed. Such suspensions (fluid mud) may create a surveying problem, owing to the multiple layering they produce on echo sounder records. Echo sounders alone do not allow an objective decision on which reflector should be regarded as the seabed for navigational purposes. A new technique has been devised involving detailed profiles of in situ density through the suspensions using gamma-ray densimeters. This information~together with knowledge of ship behavior in dense media, facilitates decisions on what values of in situ density should _ ~ be defined as the seabed. A density value of 1.2 gm/cm~ is now used by the Netherlands Rij~swaterstaat to define the "nautical depth," since research has shown that suspensions of lower density do not signif scantly impede the passage of ships . In Europoort sudden influxes of sediment during storms produce layers up to 3.0 m in thickness which are detected by echo sounders, and once the presence of such a suspension resulted in the temporary closure of the port to supertanker navigation. However, density surveys reveal that on arrival these suspensions are of very low density an~.thus ~ Hat present a. hazard to navigation. Density surveys are also used to guide the maintenance dredging fleet to areas where the 1.2 gm/cm3 density level is shallower than the nominal datum f or the channel or to areas where consolidation has progressed to a point where high production is possible.
A-16 Kondstaal, R., and J. van der Weide (1981), "Systems Approach in Integrated Harbor Planning," Publication No. 250 (Netherlands: Delft Hydraulics Laboratory), presented at the Seatech III Conference in Asian Ports Development and Dredging, Singapore, March. Abstract Port design and operation consists of an integrated series of multidisciplinary interests and requires a variety of input design criteria and boundary conditions. A systems analysis approach to port planning is presented in this report. The port is first considered as a system in the transport network linking production and consumption and the minimization of costs is discussed. The three steps in the systems approach to port planning are analysis of cargo flow, preparation of a master plan, and design of the harbor. The main elements of the master plan are shipping, site selection, conceptual plans, and dimensions. The costs of port facilities and vessels are considered, and various simulation techniques used in port planning are discussed. Kray, C. J. (1973), "Design of Ship Channels and Maneuvering Areas," J. Waterways, Harbors and Coastal Eng., Proc. ASCE, 99tWW1~: - 89-110. Abstract In view of the constant increase in vessel sizes, projects for improving channels and maneuvering areas, straightening of curves and deepening, as well as increasing the widths of the various sections of channels are being requested by navigation interests. There are basically two kinds of channels: t1) open-type, in wide waters, natural or dredged channels, often constituting the deepest portions of a bay or river, strait, or maneuvering area; and (2) restricted-type, in confined waters, excavated channel or canal, restricted inland sea extension, canal between islands, or between mainland and islands. Factors influencing the design of width and alignment of channels and dimensions of maneuvering areas required for vessels are discussed in detail in this paper. The controllability of a ship in open and in confined water is affected by the vessel' s characteristics and speed, winds, waves, currents, visibility, solid obstructions, shoaling, and traffic. The vessel behavior in channels and maneuvering areas is influenced by bottom and bank suction, interference of passing ships, rudder response, and increase in required driving power in shallow, confined waters. The Herman element involves ship operators, pilots, their reactions and attitudes, time lapse in communication' errors of judgment, and their knowledge of ship properties and the channel's configuration and peculiarities. Forces external to the ship include the effects of wind, waves, and currents on the path of ships in entrance channels and in the open-type and restricted-type waterways.
A-17 The effect of the underkeel depth in channels for ships in motion, the effects of ship location in the channel, and the effects of passing ships are also considered. The optimum direction of the entrance channel depends on forces external to the vessel, the human element, and the vessels controllability. Turns in the channel direction should not be employed unless necessary, since any change in channel direction causes changes in flow and velocities as compared to the straight section and makes navigation more difficult. The increase of channel width in bends can be considered as a function of the angle of deflection, length, beam, and controllability of the vessel, radius of curvature, and environmental conditions. The turning basin's size is a function of the length and maneuverability of the ships using them. It also depends on the time permitted for the execution of turning maneuvers. Research needs to produce reliable design criteria are identif fed as (1) influence of channel dimensions and layouts on handling of vessels, predicting their motions and rudder response, hydrodynamic mass evaluation, and optimization of geometry for channels and maneuvering areas; (2) establishment of maximum safe speeds and evaluation of increase in required driving power of ships in shallow and restricted waters; (3) ship passing phenomena, and bank suction in restricted waterways; (4) effects of reduced visibility, wind, wave, and current on vessels, particularly in difficult sections of channels; and (5) ship clearance requirements and alignment of channels and maneuvering areas. McDonald, R. M. (1977), "Development of the Ship Channel between Montreal and Deep Sea," Marine Tech., _: 192-197. Author's Abstract The dredged channel of the Ste Lawrence River between Montreal and Ile aux Coudres forms part of one of the largest inland navigation systems in the world. From the Gulf, ships can travel almost 2000 miles to the head of the lakes. The various stages of development of the channel to obtain a controlling depth of 25 ft between Montreal and Quebec City and a sufficient depth for a draft of 48 ft--with the aid of the tide--from Quebec City eastward are discussed in this paper. Mikkelsen, L., P. Mortensen, and T. Sorensen (1980), "Sedimentation in Dredged Navigation Channels," Proc. 17th Coastal Eng. Conf., Vol. II, pp. 1719-1734. Abstract The feasibility of a harbor project, which involves dredging of an access channel, may to a large extent depend on the future maintenance dredging in the channel. It is therefore important to be able to calculate sedimentation in dredged channels with sufficient accuracy.
A-18 In 1974 and 1975, the Danish Hydraulic Institute ( DHI ) carried out a study of the most feasible access charnel to Warri Port situated in the Western Niger Delta, Nigeria. Two alternative entrances were studied, and in conclusion it was recommended to improve the existing access channel through Escravos Entrance, as this solution would yield much smaller maintenance dredging quantities as compared to an access channel through Forcados Entrance. In 1978, it was decided to improve the accuracy of the sedimentation estimates for a dredged channel through Forcado" Entrance, and therefore it was recommended by DHI to dredge test pits in the alignment of the channel and to carry out a pertinent monitoring program. me paper presents: (1) The test pit monitoring program and results, including a discussion of measurement techniques, and (2) calculation of sediment transport in combined currents and waves and comparison with the monitoring results. On the basis of the test pit monitoring and the measured current and wave parameters it has been possible to calibrate the sediment transport rates in combined waves and currents. The test pit results have been used to obtain a satisfactory expression for the sediment diffusion coefficient Is and hence the concentration profile. Using the calibrated transport rates, the theoretical sedimentation model, and the wave and current statistics, it has been possible to calculate the expected annual sedimentation in the dredged channel. Further, it has been possible to predict the consequences of changes in the depth ratio D1/D2 and in the channel width and hence to produce an optimal design of the channel. In conclusion, the sedimentation model has proved itself to be a very useful tool for studies of expected sedimentation quantities, particularly if the transport rates can be calibrated through pertinent f ield studies . Minorsky, V. U. (1977), "Grounding Probability Studies, " Final Report on Task IV, Feb. 16 - Jan . 77, prepared for U.S. Maritime Administration by George C. Sharp, Inc., New York. Author's Abstract Grounding statistics for vessels over 6000 G.T. were compiled for the 6 years 1970-1975. Results were analyzed for tankers and non-tankers, each in four gross tonnage groups as to location, cause, and result. Groundings were studied in detail on proposed nuclear vessel routes with an approximate calculation of casualty probability based on route casualties and ship traffic flow.
A-19 Recommendations are given to help reduce the frequency of groundings for the nuclear vessels. Muir, William C. , G. D. Pence, and J. R. Pomponio (1981), "Deepening the Hampton Roads--The EIS Process, Eric. 14tn Annual Dredaina Seminar (College Station, Tex.: Texas A&M University). Abstract Since 1973 the foreign demand for coal has risen dramatically. The oil embargo of that year forced Europe and Japan to convert most of their energy demands from oil to coal. That demand for coal has stimulated growth in many U.S. ports, the greatest of which is the Hampton Roads complex. Last year over half of the nation's coal exports, approximately 50 million tons, came from Newport News, Norfolk, and Portsmouth which make up the Hampton Roads complex. Over the next five years, that volume is expected to double. The existing channel depth in the Hampton Roads is 45 ft. This depth severely limits the ability of larger coal colliers, greater than 80,OOO DWT, to load. The U.S. Army Corps of Engineers (COE) extensively studied the feasibility of deepening the channel to 55 ft and found it economically justifiable. In 1980 the COE prepared a Draft Environmental Impact Statement which proposed expansion of the channel to 55 ft but which presented a myriad of environmental concerns. These included such considerations as filling 6000 acres of the Dismal Swamp, the potential contamination of groundwater supplies from spoil disposal, and the changes in salinity in the tributaries to the Hampton Roads. Through the efforts of the U.S. Environmental Protection Agency and the Fish and Wildlife Service working with the COE, an extensively modified Final Environmental Impact Statement has been prepared. The final plan relies upon a mixture of dredged material disposal alternatives, including beach nourishment of clean sand, containment of contaminated sediments, and ocean disposal of the remaining material, most of which is uncontaminated. Channel deepening induced salinity changes should be more thoroughly understood as a result of extensive modeling required prior to dredging. Monitoring programs will be established to gain further insight into chemical and physical changes associated with the project. Nederlof, L. (1979 ), "Sailing Through Water Rich in Silt: A Vessel Behaves Dif f erently but Remains Manageable, " Rotterdam Europoort Delta, pp. 19-22 . Author' s Abstract . The State Waterways Department and the City of Rotterdam recently completed a study on the behavior of vessels in rivers or ports with very muddy beds. Sandy beds have a reasonably firm structure and a
A-20 silt which may be regarded as more clearly defined surface, but the composition of muddy beds is quite different. In that case there is no question of any clear profile. The vessel meets a body of water with floating particles of silt, which become more dense toward the bed. Finally there is a body of or less consolidated. The composition of such muddy beds had been hard to measure in the past, but recent new measuring techniques are making it possible to probe the structures of muddy beds thoroughly. New insights resulted which were related to the maneuvering possibilities of {very large and deep-drawing ~ vessels . The study was part of a joint research project entitled "Minimization of the Cost of Maintenance Dredging" and has given birth to different ideas about the required depths of ports and rivers . This is of interest to nautical experts because it has extended the "available water depth" notion which from now on should be judged somewhat differently insofar as muddy beds are concerned. For port managers the information is important from the viewpoint of fixing the time f or new dredging . Nederlof, L., and G. van Bocho~re t 1981 ), "Maneuvering Behavior of Ships in Muddy Canals and Harbors," The Dock and Harbor Authority, Netherlands, Vol. LXII, No. 726 (May), pp. 2-6. Abstract - Maneuverability of mammoth tankers (VLCCs ~ in silty waters has been shown to create many problems in certain harbors throughout the world. A group of researchers and scientists at the Netherlands Ship Model Basin have conducted a series of tests which are broken up into three categories or parts. The tests involve the investigation of the composition of the bed in the approach channel, the investigation of the maneuvering pattern of deep-draught tankers when passing over silt, and the investigation of the maneuvering pattern of deep-draught tankers above silt in the model tank. Tests were run to determine the composition of the bed using a radioactive density indicator, and the results showed that deposition of silt was particularly heavy in the period toward the end of the year. Test results of a deep-draft tanker when passing over silt showed that the passing vessel sets up a stern wave at the interface of water and silt, the density of the silt does not change during the passage, and when the ship is passing, a layer of silt is brought into suspension. The model results showed that the resistance is much greater in silt and requires higher propeller revolutions, the stopping distance is reduced, the squat and trim are less, the effectiveness of the rudder increases sharply, and the effectiveness of the propellers is not constant.
A-21 Ottevanger, G. (1979), "Dredging Operations in the Approaches to Rotterdam," Land and Water International, pp. 27-32. Abstract The advantages of the trailing-=uction hopper dredger over dredging equipment used prior to 1957 in the Nieuwe Maa" and the Rotterdam Waterway are discussed in detail. A description of the electronic position-fixing equipment used on these dredgers is presented. Details are given of the execution of the dredging and disposal operations, as well as of the supervision of the maintenance dredging. New developments f or trailing-suction hopper dredgers include the recording of positional and loading data on magnetic tape for computer analysis, and a probe which continuously monitors the loading pattern of the dredger. Survey echo sounders and systems for position-fixing of the draghead are now being developed. Trawle, M. J. (1981a), "Prediction of Shoaling Rates for Deepened Estuarine Navigation Channels, " Proc. 14th Annual Dredging Seminar (College Station, Tex.: Texas A&M University). Abstract ~ . This paper presents an empirical method of shoaling analysis based on historical dredging and shoaling records that results in reliable predictions of future shoaling for deepened channel conditions occurring either from an increase in authorized channel depth or from The method presented was designed to be general enough that it can be applied to most navigation projects without difficulty. - ~ ~ ~ ' ' ~ , advance maintenance. TO demonstrate how the method would be applied to real navigation projects, the Texas City Channel in Galveston Bay, Texas, was evaluated and results were discussed. Trawle, M. J. (1981b), "Effects of Depth on Dredging Frequency: Methods of Estuarine Shoaling Analysis, Technical Report H-78-5 (Vicksburg' Miss e Ue S e Army Engineer Waterways Experiment Station) e Author's Abstract Whenever deepening,,of a dredged channel is under investigation, a prediction must be made as to the effect of the deepening on the existing dredging requirements. If the deepening is related to advance maintenance dredging rather than to an increase in authorized depth, the prediction becomes even more difficult because the project is allowed to shoal over a wide range of depth. Currently, a variety of arbitrary, rule-of-thumh procedures are used for predicting the effect of increasing depth on dredging requirements. The overall objective of this investigation was to evaluate the effectiveness of advance maintenance dredging in reducing dredging frequency and/or costs An the maintenance of coasted channels and.
A-22 harbors and to establish necessary guidelines for governing the practice. This report, the second of a series, presents an empirical method of shoaling analysis based on historical dredging and shoaling records that results in reliable predictions of future shoaling for deepened channel conditions resulting either from an increase in authorized channel depth or from advance maintenance. The method presented was designed to be general enough that it can be applied to most navigation projects without difficulty. The procedure was described step-by-step using an example (fictitious) project. To demonstrate how the method would be applied to real navigation projects and to point out problems that occur when evaluating real projects, selected Galveston Bay, Texas, navigation projects were evaluated and the results discussed. Trawle, M. J., and J. B. Herbich ~ 1980 I, "Prediction of Shoaling Rates in Offshore Navigation Channels, " Center for Dredging Studies, Department of Civil Engineering Report No. 232 ~ College Station, Tex.: Texas A&M University). Abstract This report discusses several techniques in use for prediction of future dredging requirements whenever enlargement of estuarine/coastal entrance channels is considered. The dredging requirements of six selected entrance channels for both the existing dimensions and the immediately previous dimensions were determined to evaluate the "volume of cut" prediction technique. The six projects, selected on the basis of availability of historical dredging data, were the Wilmington Harbor entrance channel in North Carolina, the Pascagoula Harbor entrance channel in Mississippi, the Calcasieu River entrance channel in Louisiana, the Sabine-Neches entrance channel and the Galveston Harbor entrance channel in Texas, and the Yaquina Bay and Harbor channel in Oregon. The adequacy of the "volume of cut " technique is i nvestigated by predicting the dredging requirements f or the existing project from the previous project dredging requirements. The results, although based only on a limited number of proj eats, suggest that the "volume of cut" technique can be a valuable tool during the preliminary analysis of a proposed entrance channel enlargement. While the "volume of cut" procedure for predicting future dredging requirements for enlarged entrance channels, as described by the limited investigation conducted for this paper, is a rather simplistic approach to a very complex problem, analysis of the data does indicate a significant correlation between "volume of cut" and dredging requirements. A more detailed examination of the reliability of this method of prediction would necessitate the inclusion of other factors, not considered here, which can affect shoaling in an estuarine/coastal environment. Such factors include the effects of tidal action, channel alignment, littoral drift, storms, and wave action. The results of this report indicate that even a basic
A-23 analysis using the "volume of cut" procedure, without considering any of the above-mentioned factors, would aid significantly for prediction purposes in the preliminary stages of project design. Troesch, A. W., and S. Cohen (1980), "Relationship of Underkeel Clearance and Vessel Speed to Grounding," Report No. 017999, Ship Hydrodynamics Lab, University of Michigan. Abstract The linkage, trim and underkeel clearance of the lead barges in a 3 x 3 barge train were measured. The barges represented typical Mississippi River barges. The tests were conducted in response to a USCG request to investigate groundings due to channel depth decreases. The water depth varied from 2.6 to 1.05 times the barges' draft. There were two bottom contours: one with constant depth and one with an underwater obstacle in the form of a step. The speed of the barge train was varied from 2 kn to 8 kn, full scale. Turner, H. D. (1978), "Physical Model Study for Improved Navigation Channel Design," 26th Proc., Annual ASCE Hydraulic Div. Spec. Conf.: Verification of Math. and Phys. Models in Hydraulic Eng., University of Maryland, August 9-11, pp. 265-272. Abstract The U.S. Army Engineer Waterways Experiment Station (WES) is conducting a study to determine the minimum dimensions of deep-draft navigation channels for safe and efficient navigation. The model study is focused on the improvement of navigation channel design methods and uses free-running, remote-controlled scale models of prototype ships as a means of evaluating the channels being tested. Present navigation channel design criteria in the United States were formulated in 1965 and are based on the 1948 tests during the Panama Canal sea level project. The width allowance is from 2.8 to 5.O times the design ship's beam for one-way traffic and 5.2 to 8.0 times the beam for two-way traffic. The width criterion depends on judgment factors relative to design ship controllability, strength of yawing forces, quality of navigation aids, type of channel, and bank orientation. The depth allowance is the stem of ship draft, salinity effects, wave action, squat, and underkeel clearance. The design of navigation channels is influenced by many factors, such as ship dimensions, ship power to weight ratio, ship rudder and propeller assemblies , type of traffic (i.e., one-way, two-way, overtaking, ship speed, pilot ability, and environmental conditions (i.e., wind, waves, fog) . In the model testing program, changes In ship draft, ship speed, channel width, and channel depth will be evaluated. The testing facility consists of two straight channel reaches connected with a typical bed ~ the mid arid a tang basin at each ends T"awr
A-24 the study, wind generators and a wave generator will be placed in the turning basin to simulate wind and wave effects on navigation at entrance channels. During a typical test run, time-based data such as ship speed, rudder angle and ship heading will be collected and analyzed to determine the safety of the channel. A test channel will be declared unsafe if an excessive amount of rudder is required to successfully navigate the cannel or if the model ship comes too clone to either the aide or the bottom of the channel. The test results will be compiled and used to construct design curves which define both channel and ship parameters. Similar design curves will be developed for various types of traffic, ships, navigation aids, pilot skill, and environmental conditions. van de Ridder (1979), "Rotterdam and the Harbor Silt," Land and Water International, pp. 23-26. Abstract Maintenance dredging in the Rotterdam harbor basins is carried out by two methods: (1) bucket dredger operations and storage of spoil ashore and (2) trailing-suction dredger operations and damping at sea. This paper describes the technical aspects of both of these methods. The advantages of bucket dredgers are discussed, and the increased production obtained after introduction of density measurement instruments for determining nautical depth is outlined. The transportation of the spoil to the discharge area by barges and pipelines is also discussed. Trailing-suction dredging operations are described for the period from 1963 to 1977 in the Europoort and Botlek areas. The problems involved in utilizing the full hopper capacity in both the winter and the Sumner months and in disposing of silt contaminated by pollutants are also discussed. van Don~elaar, H., et al. (1981), "The Maritime Impact of Liquid Energy Gases--the Planning and Operational Aspects," Maritime Ports and Seaways, Vol. I, Permanent International Association of Navigational Congresses, XXV, Sec. II. Abstract This report treats a certain number of aspects concerning the large-scale importation of liquefied gas into the Netherlands. The world's energy situation is briefly described, and arguments are presented for the Importation of energy gases by the Netherlands. The risk" involved in the transport of liquefied gases by seagoing vessels are discussed, and the factors governing the Dimensions of channels and harbors are outlined. Information is given on the relationship between the "hip behavior and the Dimensions of the navigation
A-25 channel. Operational aspects, such as the regulation of traffic and ship-related safety measures and procedures are also considered. The results of traffic simulations of ships transporting liquefied gas are presented. Various implementation aspects are discussed with reference to existing harbors, a new shore-based harbor and an offshore harbor. The report conclude" with some comments on dredging aspects of the activities involved with the adaptation of existing harbors or the construction of new ones. van Oostrum, W. H. A. (1979a), "Maintenance Dredging in Soft-Bedded Navigation," Control Dredging Association (CDEA) Conf., Netherlands. Abstract This paper describes the problems and solutions in the process of maintenance dredging. The discussion includes the siltation process and the concept of nautical depth in a soft-bedded channel. A comparison of the advantages and disadvantages of density measuring probes and echo sounders is presented. The automation of data collection, data handling, and data presentation is discussed for the dredging and surveying operations. The dredging program and dredging decision are considered in terms of a programmed decision making model. The final item considered is the marketing policy, especially the ways in which to acquire the necessary capacity for dredging. van Oostr~m, W. H. A. (1979b), "MKO Project," Land and Water International, pp. 17-19. Abstract The aim of the MKO project is to study scientific, technical and economic possibilities for reducing the costs of maintenance dredging operations. The research project has been divided into three main parts: (1) studies of the morphological--and other--aspects of sedimentation, (2) research into dredging techniques, and (3) research into marketing and business economics. This paper considers part 1 in detail and briefly discusses part 2. The sediment transport balance in the waterway area is analyzed, and several means of reducing the amount of sediment to be dredged are suggested-. The effects of a silt trap placed at the mouth of Europoort are described, and the methods of measuring the density of silt deposits are outlined. The paper indicates possible solutions to the problem of recirculation of silt from the damping ground at sea to the harbor entrance. A brief discussion of the programming dredging method and continuous hopper measurement system is included.
A-26 van Oostrum, W. H. A. (1979c), "Operations Research in Dredging," Terra et Aqua, _: 2-15. Author's Abstract Modern dredging equipment constitutes a large capital outlay and is expensive to run. Therefore attempts are being made continuously to boost and to raise efficiency. In particular, attention has been given to improving the mechanical and technical components of the dredging system. During the last decade more and more electronics have entered dredging technology. Parallel to this, extensive developments have taken place in the f ield of hydrographical surveying. More recently attempts have been made to raise output in paid m3 by improvement of the management of dredging operations. Computerized data-handling systems form the unavoidable basis for a further integration of the basic activities of dredging work. The large capital and maintenance dredging works in the Rotterdam-Europoort area form an ideal test field to develop more efficient dredging methods. Operations research techniques are playing an increasingly important role and several pro j eats in this f ield have already led to practical results such as programmed dredging, flight recorders, survey and positioning automation routing programs and navigation programing. AS a binding element, computerized data-flow connects all these applications. Although most applications are related to dredging works executed by self-propelled suction hopper dredgers, the methods are suitable f or stationary dredging as well. van Oostrum, W. H. A., W. R. Parker, and R. Kirby ~ 1980 ), " - intenance Dredging in Fluid Mud Areas, " Third Int. Symp. Dredging Tech., Bordeaux, France, pp. 177-190. Author' s Abstract Recent work has shown that most mud dredging problems arise from the penetration of harbor basins and channels by dense mobile near-bed layers . When these layers stagnate , rapid deposition occurs, f orming f luid mud layers which exhibit characteristics transitional between true seawater and the seabed. These deposits present particular dredging problems and cannot be dredged efficiently at the present tome. Is a result of-~he ine-ff~c~ency of con vend; maintenance -- dredging other alternatives may be adopted to decrease the dredging requirement. Examples discussed are the location of port facilities in zones of low sedimentation or prevention of silt penetration using locks, bubble curtains or removable barriers. Where siltation cannot be avoided it may be handled more efficiently, depending on local circumstances, by other concentration into traps or spreading. In many areas of very high sedimentation the only way to cope with the large sediment flux is by agitation dredging.
A-27 In fluid areas still dredged by conventional trailer-suction dredgers, increases in efficiency and production must be sought in improvements in surveying methods and in the design of dredging plant. In this connection density measurements are replacing conventional echo sounding surveys. The value of density surveys is that they provide repeatable information on seabed characteristics which are directly applicable to dredging requirement" and to the navigation of ships. Complementary developments of dredging systems directed both to trailer-suction dredgers themselves and also to the development of novel concepts such as stationary dredgers with the complete removal of spoil from the local water circulation, point the way to major increases in efficiency. van Oostrum, W. H. A., et al. (1981), "Dutch Efforts for Opt ~ cation of Marine Dredging," Proc. XXV Int. Nav. Cong., Inland and Maritime Waterways and Ports, PIANC, Section II, Vol . 2, Edinburgh, Scotland, May 10-16. Abstract A review of the present state-of-the-art in various fields of the dredging industry is presented. The discussion includes surveying methods, the nautical depth concept, overdredging, positioning system, sampling technique-, dredging automation, and cost estimates. Wang, S. (1980), "Full-Scale Measurements and Statistical Analyses of Ship Motions in a Navigational Channel," Marine Tech., 17: 351-370. Author' s Abstract Due to the trend of large dry and liquid bulk carrier construction in recent years, safe navigation in ports and channels has been a great concern to both the governmental regulatory agencies and the merit Me industries. This paper presents the results of a study on motions of deep-draft vessels in a navigation channel. The objective of this study was through measurement and analysis of the vessel motions to validate the design assumptions for a specific channel as well as to establish the general design information on channel width and depth requirements, with respect to the ship characteristics and channel environments. Full-scale measurements of motion characteristics for 29 vessel transits through the Columbia River Entrance Channel have been conducted. The measurements include pitch , heave and roll motions, vessel heading angles and position tracks. Analyses of the measured data have been conducted with the objective to derive both the short-term and long-term statistics. For short-term correlations, all the motion variations have been assumed stationary, and comparisons of the histograms of motion amplitudes with the theoretical Rayleigh
A-28 distribution have been conducted and found satisfactory. AS to the long-term statistics, it is found that the measured data can be very well represented by the log-normal distribution. Waugh, Richard G., Jr . ~ 1971 ), "Water Depthe Required for Ship Navigati on, " J . Waterways , Harbors and Coastal E:ng., Proc . ASCE, _(WW3~: 455-473. ~ Abstract The state-of-the-art in the selection of channel depth is briefly reviewed to emphasize the fact that channel depth design in the United States has been more a matter of judgment than one of rigorous engineering analysis. The factors influencing the choice of channel depth are discussed in detail. The recent increase in ship sizes is outlined and a tabulation of channel depths in world ports is presented in the Appendix. While the largest man-made federal navigation channel in the United States to accommodate bulk commerce has an effective depth of 45 ft. excluding additional clearances over the ocean bar, several dredged channels in foreign ports have depths exceeding 60 ft. Changes in water salinity and temperature influence the density of water and vessel draft. The trim of the vessel as loaded must also be considered in channel depth design. For many vessels, trims of 1 ft to 2 ft at rest are not uncommon. Normally, a 1 ft allowance is provided in selecting the channel depth. Vessel squat is a function of the vessel speed, water depth, wetted cross section of the vessel, and the width and section of the waterway. It can be shown that squat is also affected by the location of the vessel in the waterway, the trimness of the vessel's lines , and the presence of other vessels in the same cross-section. Although vessel squat can be computed accurately in well-defined, regular sections, little is known of vessel squat in deep and wide waterways. Changes in trim while under way may cause the stern of the vessel to slam the bottom as its speed increases. AS the vessel approaches the channel banks, its squat will tend to increase. The presence of passing vessels will also increase the squat due to the reduction of water area. The influence of waves on the ship motion and draft must be taken into consideration, particularly in the ocean entrance channels. After-~llowan~es have DO~D - made;fa=~ncreases za ~ vessel's draft due to squat, trim, freshwater density,and wave motion, an additional allowance is added by the Corps of Engineers. The general practice has been to provide 2 ft of clearance between the vessel's keel and the channel bottom in soft material and from 3 ft to 4 ft where rock is encountered. Although primarily for safety, this clearance increases vessel operating efficiency because under shallow water conditions, the speed decreases, the resistance increases, and the rudder response becomes more sluggish.
A-29 The information available i" inadequate to determine the safe navigation depth required for vessels moving in restricted channels. It is believed that the most critical single factor in channel depth design is Pretzel squat. While some data have been accumulated for vessel. in canals, little i. known of the Pretzel phenomena that take place in irregular-shaped channels Ad estuaries. Wicker, C. F. (19711, "Economic Channels and Maneuvering Areas for Ships , ~ J . Waterway. , Harbors and Coastal Eng ., Proc . ASCE , _ 97 (WvI3 I: 443-4~4. Abstract Me state-of-the-art involved in the design of a ship channel is briefly reviewed to stress the lack of knowledge concerning the channel depths, widths, and all ~ ents necessary for safe navigation. The --election of the channel depth depends on factor" such as squat, change. in draft, due to differences in water density, ship response to waves, and underkeel clearances required for large vessels to maintain a given speed in shallow depths. However, little is known about squat in narrow, deep channels in estuaries, or the effects of passing vessels, channel banks, and poor tram on squat. Ship response to waves and power requirements for large vessels in shallow waters are also not well defined. The design width of a channel depend" on the handling characteristics of the vessels using the waterway and the effect" of winds, waves, and currents on vessel heading. However, reliable information on the effects of passing vessels, channel banks and varying conditions of operation and loading is not provided to channel designers. The width of the channel at the turns is considerably wider than the straight reaches. Although the vessel length, speed of travel, rudder response, and proximity of the banks should be considered in dete ~ ning the Amount of turn, there are no data on the coefficients to be applied in the relationship. As a result, channels are generally planned in accordance with the best depths in a natural waterway, or to minimize excavation, with little attention to the needs of navigation. A comparison of costs for a hypothetical excavation using 2 ft overdepth with maintenance dredging is made for an overly Conservative channel design and an adequate, safe channel to illustrate the excessive cost of making the channel wider and deeper than necessary. Another cost comparison i" made between an unsafe channel and an adequately safe channel, to demonstrate that the apparent savings involved in a minims channel are likely to be exceeded by the potential loaves due to accidents, loss of life, loss of vessels, costs of removal of wrecks, vessel delays, and cleanup of pollution. A discussion of the factors involved in the design of navigation channels includes environmental considerations such as the tidal range, currents, waves, water densities, ice conditions, meteorological conditions, geometry of the waterway, bottom materials, .
A-30 considerations such as length, beam, are also and shoaling potential. Vessel static draft, trim, cruising speed, and controllability are also discussed. Factors to be considered for vessel operation in channels include speed and spacing regulations, density and frequency of transits, overtaking or meeting ves=61s, and mix of vesee1e in the traffic pattern. The human factor of pilot decisions must also be included. Human failures can involve a lack of knowledge of the channel inadequacies or the vessel peculiarities, a lack of skill, a tendency to risk-taking, or a lack of complete attention. With increasing vessel size and cost, navigation channels must be deepened and widened, and the designer must be provided with the necessary knowledge to design safe and economic channels. Yeung, R. W. (1978), "On the Interactions of Slender Ships in Shallow Water," J. Fluid Mech., 8S: 143-159. Author's Abstract The unsteady hydrodynamic interaction of two bodies moving in a shallow fluid is exams ned by applying slender-body theory. The bodies are assumed to be in each other's far field and the free surface is assumed to be rigid. By matched asymptotics, the inner and outer problems are formulated and a pair of coupled integro-different' al equations for determining the unknown cross-f lows is derived. The degree of coupling is shown to be related to a bottom-clearance parameter. Expressions are given for the unsteady sinkage force, trimming moment, sway force and yaw moment. Numerical calculations for two weakly-coupled cases are presented. One corresponds to the interaction of a stationary body with a passing one, the other to the interaction of two bodies moving in a steady configuration. Theoretical results are compared with existing experimental data. Zahn, A. S. (1977), "Grounding Characteristics and Effects," Final Report on Task 5, Oct. 76 - Jan. 77, prepared for U.S. Maritime Administration by George C. Sharp, Inc., New York. Author's Abstract Data on the details of 52 groundings were collected f ram the f iles of IMCO and U~CO from L944. to 1975. Cases are identified by number or name, flag, type , tonnage and characteristics. Information lists repair costs, location of casualty, weather, cause of grounding, speed of impact, information on double bottom condition; Damage location, description, length, width and depth ; also type of sea bottom. The data have not been analyzed.
