Ship Draft Research Articles

Impacts of Ship Waves on Bed Morphology of a Trapezoidal Cross-Sectional Channel

Abstract Ship waves could alter the hydrodynamic field and play an important role for sediment movement and morphological changes, especially in shallow water regions of inland waterways. However, the response of riverbed morphology to ship waves is still unclear. In this paper, the impacts of ship waves on the bed profile in inland waterways are investigated by means of laboratory experiments. Observations of ship waves and bed profile changes exposed to different ship wave conditions are conducted. There exists a power exponential relationship between the corresponding polygon area and perimeter of the cross-sectional bed profile after the action of ship waves, which indicates that the bed profile is only adjusted in the geometric direction. Moreover, the dimensionless local scour depth is well predicted through the dimensionless expression of ship-induced near-bed velocity, ship draft, and offshore distance, which describes the impacts of ship waves on the bed morphology in inland waterways.

The Impact of Improving the Quality of the Port’s Infrastructure on the Shippers’ Decisions

Important attributes of a transportation chain are the costs of their operation, the security of supply they provide, and reducing carbon emissions throughout the chain. When making managerial decisions about the chain configuration, shippers consider the optimal choice of means of transport, carriers, or ports. Seaports, as transport nodes, determine the functioning of supply chains they serve. A constant process observed in the world shipping is the consistent increase in the average size of ships. Adapting the port and port access infrastructure to the changes observed in the world shipping is a prerequisite for maintaining the competitive position of the port, and consequently of the entire transport chain. Adequate hydrological conditions ensuring safe access to ports for increasingly larger ships are necessary for the stable functioning and development of a port and the entire region. For shippers, the certainty that the handling of larger vessels is assured regardless of any fluctuating hydro-meteorological conditions and temporary vessel entry permits is a guarantee of security of supply. This study aims to demonstrate the impact of fairway deepening on port-oriented supply chain costs and security of supply, as well as verification of the importance of these factors for cargo shippers’ decision-making. The article used the case study method based on the port of Szczecin, for which the investment of deepening the fairway to 12.5 m is being implemented. The article estimates the transport costs of five transport chains served by the port of Szczecin. Our research showed that a 2.5 m increase in the permissible draught of ships results in a decrease of up to 25% in transport costs resulting mainly from the reduction in specific fuel consumption throughout the chain. The analysis of the results showed that a secondary benefit of deepening the fairway can change the structure of the port’s foreland. This conclusion was validated by means of in-depth interviews held with selected shippers cooperating with the port of Szczecin. An additional outcome of the interviews was identification of the remaining conditions that should be met to take full advantage of improved port accessibility. The research is the first step to broader studies assessing whether improving quality of port infrastructure can contribute to a reduction in emissions from ships in a port and thus facilitate the transition to zero-emission ports.

Analysis of Trends in Mega-Sized Container Ships Using the K-Means Clustering Algorithm

The size of ships is increasing rapidly, and over 400 m length overall mega-sized container ships are predicted to appear in the near future. Consequently, studies on large container ships have been conducted; however, based on the 30,000-TEU (twenty-foot equivalent unit) class container ship’s length overall, the deviation of the predicted range showed an 83.9 m difference from 453.0 m to 536.9 m. This is because simple linear regression analysis does not consider trends according to the type of cargo or the size of the cargo. In this study, 5497 container ships up to 20 years of age with an International Maritime Organization (IMO) number registered were clustered according to the change in ship dimensions by k-means clustering algorithm. Based on the clustered data, deadweight tonnage, TEU, length overall, length between perpendiculars, breadth, and maximum draft of container ships with a coverage rate of 75% were analyzed to predict the change in the main dimensions. The results indicated that for a 30,000-TEU container ship, the predicted length overall is 428.4 m, breadth is 67.6 m, and draft is 17.0 m. This study can help minimize the social costs of designing ports in consideration of future mega-sized container ships.

İstanbul Boğazı’ nda deniz kazalarının seyir emniyeti perspektifinde incelenmesi: İSTANBULMAKS gemi tipi önerisi

In this study, maritime accidents that occurred in the Strait of Istanbul over a 10-year period were evaluated in terms of ship-based risk factors. The frequency analysis was performed using the R - Studio program language. In this context, the accident data obtained from the Ministry of Transport and Infrastructure Main Search and Rescue Coordination Center were matched with the ship information accessed from Türk Loydu database. Thus, ship origin risk factors to be used within the scope of the study were determined and 10 different criteria were included in the analysis. These are ship length, ship breadth, ship draught, ship age, ship DWT, turning point, turning radius, L/B ratio, B/T ratio and number of propellers. The process of creating a data set was completed by spatially filtering the data and classifying of the ship-based causes accidents. The variables were examined with frequency analysis in the perspective of the Law of Large Numbers. With the results obtained, optimum characteristics based on ship origin risk factors have been revealed for each ship type that will pass through the Strait.

Column-Based Waterline Detection for Lightweight Ship Draft Reading

Draft reading is a common means to measure the amount of cargo loaded on a ship in the maritime industry, and waterline detection is a key technology in this regard. A variety of factors limits traditional edge detection-based waterline detection methods. They are challenging to apply to different situations. Existing deep learning-based methods do not consider the specificity of the task and have disadvantages such as complex processing flow and insensitivity to the waterline. This article proposes a novel column-based selection method that treats waterline detection as a classification problem. Compared with the current pixel-wise segmentation, the proposed method can effectively reduce the computational cost. Based on the proposed method, we also introduce a structural loss. By introducing spatial constraints, the accuracy of the location selection is further improved. Moreover, we propose a simple architectural unit to accomplish draft mark detection, which effectively enhances the lightweight in draft reading. The experimental results on the real-world datasets demonstrate the state-of-the-art performance of the proposed waterline detection method. In addition, the average error on the draft reading task is 0.27 m, and the processing speed achieves 25+ frames per second with a resolution of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$544 \times 960$ </tex-math></inline-formula> .

Geographical Condition And Port Development

The first-time purposely build container ships introduced in 1967 with a draft of 9 meters, and now, newer container ship drafts can reach 16 meters and more. The development of the container ship dimension is rapid. Ports respond to these changes and keep up with the more significant size and a deeper draft of the new container ship design. Ports are developing their infrastructure from installing gantry cranes to dredge their seafloor. This research reviews that phenomenon and studied how ports adapt to the changing container ship dimension, especially for Post Panamax container ships built for efficiency. To do that, we use an exogenous variable of ports' depth from 1972 to 1985 before the ports knew that they would need deeper depth to accommodate such ships. We find that ports with actual depth more or equal to 13.716 meters is significantly affected port to accommodate Post Panamax container ship in this present time. The scope of this research is to show how a port responds to the change of the dimension of a container ship. Nevertheless, this research can be a steppingstone to measure the causality of trade that never has been done correctly before by introducing an exogenous variable that is strong, which port’s depth regarding the Post Panamax container ship draft.

Opinion: To save whales, look to the sky

Human activity threatens whales. Whale populations face indirect impacts such as ocean noise and pollution, as well as direct impacts from whaling, fishing gear entanglements, and ship collisions (1). Such collisions are believed to kill about 80 whales on the US West Coast each year (2). Although precise estimates have not been tabulated, whale deaths likely amount to several thousand annually worldwide. Simple steps could reduce this toll, but these have yet to be put in place in a systemized way (3⇓–5). With maritime traffic expanding, the threat to whales can be expected to increase. It is therefore critical that we investigate what can be learned from the management of other transport systems to reduce collision and improve whale conservation. Shipping routes have been compared with roads, and concepts from terrestrial ecology have been borrowed to assess the direct and indirect ecological impacts from shipping on marine giants (6). For example, some have suggested that the addition of transition zones adjacent to maritime routes may help buffer the spread of shipping environmental impact. We extend this approach to draw lessons from the aviation industry on how to manage collisions with wildlife, lessons that point to crucial steps for better protecting the ocean’s whales (Fig. 1). Fig. 1. The aviation industry offers useful lessons for the shipping industry on how to manage wildlife collisions, which point to crucial steps for better protecting whales. Image credit: Shutterstock/Manamana. Fig. 2. Comparing the primary features of wildlife–vehicle collisions among four transportation industries highlights important differences and commonalities. Whale–ship collisions share more characteristics with bird–aircraft collisions than with terrestrial wildlife–vehicle collisions. There are some key theoretical similarities with the aviation industry (Fig. 2). Both whale–ship and bird–aircraft collisions occur in three-dimensional space. Ship draught can reach a depth of 20 m, and some whale … [↵][1]1To whom correspondence may be addressed. Email: maxime.sebe{at}polytechnique.edu. [1]: #xref-corresp-1-1

Разработка способа автоматизированного определения осадки судна с использованием технологий машинного обучения

This paper discusses the process of ship draft measurement known as draft survey. The purpose of the study was to improve the accuracy of draft survey results and the efficiency of this procedure itself. The study relies on video footages of draft marks, as well as clinometer readings, following the methods of digital image processing, machine learning, digital signal processing, linear filtering and applied programming. The tools developed as a result of this work are based on machine-learning algorithms and can perform draft surveys even in bad weather. Accuracy limits depend on camera resolution, lighting and weather conditions. Combined with linear filtering algorithms and ship inclinometers, this technology might offer draft survey tolerances as narrow as several millimeters, thus being well above its existing counterparts. Automated draft survey method suggested in this paper will make cargo weight measurements of bulkers more accurate, thus saving time and money, as well as making survey results independent on human error. Relying on machine-learning and computer-vision technologies, this method is universal and will work with any type of ships. Theoretical value of this study is that it gives a comprehensive review of what ship draft is and how it is measured.

HULL VANE INVESTIGATION WITH NACA 4412 ON VARIATION ANGLE OF ATTACK AND POSITION

Fuel efficiency is the goal of every ship, the accuracy of the motor selection, propulsion efficiency, as well as in the hull design for reducing drag. There have been many innovations in ship hull forms, such as the bulbous bow, transom steering, changing shape and becoming a multihull. This study adopted the NACA 4412 experimental as a Hull Vane® that other researcher carried out and perform with CFD simulations, then compared them with experimental results. The suitability of the trend can be further developed by varying the angle of attack from NACA and changing its position to the hull. The angle of attack variations on 1o, 2o, 3o, and positions change to the ship draft and AP-after perpendicular. Changes in the angle and position of NACA were investigated of their effect on the resistance component. From the analysis of the wave resistance, the most magnitude resistance decrease founded at the NACA position at a distance of 40 mm Trailing Edge of ship Draft and 85 mm Trailing Edge of AP. The lowest wave resistance was generating by the angle of attack of 3o, with a significant decrease of 19% compared to 1o. The more considerable lift drag was obtained after Fn 0.3 from NACA at an angle of 3o and the smallest at 2o. This investigative study was presented in graphs and data as well as conclusions and discussion of the results.

PENGARUH THRUST DEDUCTION FACTOR DAN WAKE FRACTION TERHADAP EFISIENSI PROPULSI AKIBAT PERUBAHAN DRAFT KAPAL

This study is to investigate propulsion efficiency due to changes in draught of ship using data series and theoretical approach. A hard chain rescue boat with triplet screw was used for the study and to examine the effect of thrust deduction factor and wake fraction due to changes in draught of ship and its relevance to propulsion efficiency by observing hull and propeller interaction based on openwater test by Wageningen Data Series with cavitations analysis has been neglected. The study is done using hydrodynamics analysis for planning hull and using intersection between thrust characteristic curve with openwater test data series for fixed pitch propeller. The result indicated that the changes in ship draught are very influential on the changes in thrust deduction factor and wake fraction value which is one of the contributing factor to change the propulsion efficiency value 1% - 5%.

Roll characteristics contributed by a bilge keel using a high-order fractional step finite volume solver

This paper follows the previous work [Ocean Eng 199: 1–15] to study roll characteristics contributed by a bilge keel through investigating the differences between roll characteristics of the naked mid-section of a KVLCC2 and the ones of the hull fitted with a bilge keel. Harmonic excited rolls are simulated by a high-order fractional step finite volume solver. Roll moment, roll damping, added mass moment of inertia, hull pressure are explored. Besides, two damping components of a bilge keel, due to the force normal to the bilge keel and the additional pressure on the hull induced by the bilge keel, are studied. Five parameters, namely roll amplitude, roll frequency, ship draught, height and thickness of the bilge keel, are concerned. In results, the additional roll moment due to the bilge keel exhibits a strong nonlinearity. The two components contribute to the additional roll moment quite the same amount, whereas wave radiation contributes little and negligible. Added mass moment of inertia is saturated when roll amplitude becomes large. Hull pressure induced by the bilge keel is normally positive at the front of bilge keel and negative at the back side and attains maximum approximately right at the base of the bilge keel.

The System Research and Implementation for Autorecognition of the Ship Draft via the UAV

The reading of the ship draft is an important step in the process of weighing and pricing. The traditional detection method is time-consuming and labor-consuming, and it is easy to lead to misdetection. In order to solve the above problems, this paper introduces the computer image processing technology based on deep learning, and the specific process is divided into three steps: first, the video sampling is carried out by the UAV to obtain a large number of pictures of the ship draft reading face, and the images are preprocessed; then, the deep learning target detection algorithm of improved YOLOv3 is used to process the images to predict the position of the waterline and identify the draft characters; finally, the prediction results are analyzed and processed to obtain the final reading results. The experimental results show that the ship draft reading method proposed in this paper has obvious effects. The method has a good detection effect on high-quality images, and the accuracy rate can reach 98%. The accuracy rate can also reach 73% for the images with poor quality caused by improper capture, character corrosion, bad weather, etc. This method is a kind of artificial intelligence method with safe measurement process, high measurement effect, and accuracy, providing a new idea for related research.

Computer vision with deep learning for ship draft reading

The draft is a measurement of the vertical distance between the waterline and the bottom of the ship hull. The displacement tonnage of a ship then can be calculated by the observed draft. The current draft survey is done by surveyors, which is subject to human errors. We propose to use computer vision with deep learning for draft reading from images. First, mask R-CNN is used to segment the region of interest—draft marks and water—from images. Then UNet is used to refine the waterline detection. The detection of marks is based on the computer vision methods and the content of marks is recognized by ResNet. Finally, we can infer the draft of a ship based on the extracted visual information. Experimental results on a realistic dataset have shown that the proposed method can perform the task of draft reading on a par with humans.

Development of a Fuel Consumption Prediction Model Based on Machine Learning Using Ship In-Service Data

As interest in eco-friendly ships increases, methods for status monitoring and forecasting using in-service data from ships are being developed. Models for predicting the energy efficiency of a ship in real time need to effectively process the operational data and be optimized for such an application. This paper presents models that can predict fuel consumption using in-service data collected from a 13,000 TEU class container ship, along with statistical and domain-knowledge methods to select the proper input variables for the models. These methods prevent overfitting and multicollinearity while providing practical applicability. To implement the prediction model, either an artificial neural network (ANN) or multiple linear regression (MLR) were applied, where the ANN-based models showed the best prediction accuracy for both variable selection methods. The goodness of fit of the models based on ANN ranged from 0.9709 to 0.9936. Furthermore, sensitivity analysis of the draught under normal operating conditions indicated an optimal draught of 14.79 m, which was very close to the design draught of the target ship, and provides the optimal fuel consumption efficiency. These models could provide valuable information for ship operators to support decision making to maintain efficient operating conditions.

Analysis of plated-hull structure strength against hydrostatic and hydrodynamic loads: A case study of 600 TEU container ships

Abstract The assessment of a ship's ability to withstand environmental loads is very crucial. This research focuses on the strength assessment of 600 TEU container ship hulls against hydrostatic and hydrodynamic loads using finite element-based software. Parameter changes in the material types, hull thickness, and ship drafts were performed to compare the structural responses using deformation, strain, and von Mises stress criteria. All of the materials tested were acceptable, where the ASTM A131 Grade AH36 and ASTM A131 Grade AH32 materials have the lowest deformation values and strains. The simulation results regarding plate thickness variation, deformation, strain, and von Mises stress values were smaller as the thickness of the ship structure increased. Moreover, from the draft variation, the structural response due to environmental load was better as the draft of the ship increased.

Grounding-aware RRT⁎ for Path Planning and Safe Navigation of Marine Crafts in Confined Waters

The paper presents a path planning algorithm based on RRT* that addresses the risk of grounding during evasive manoeuvres to avoid collision. The planner achieves this objective by integrating a collective navigation experience with the systematic use of water depth information from the electronic navigational chart. Multivariate kernel density estimation is applied to historical AIS data to generate a probabilistic model describing seafarer's best practices while sailing in confined waters. This knowledge is then encoded into the RRT* cost function to penalize path deviations that would lead own ship to sail in shallow waters. Depth contours satisfying the own ship draught define the actual navigable area, and triangulation of this non-convex region is adopted to enable uniform sampling. This ensures the optimal path deviation.

Real time Energy Efficiency Operational Indicator: Simulation research from the perspective of life cycle assessment

CO2 emissions during ship building, maintenance, and scrapping are not be involved when defining Energy Efficiency Operational Indicator (EEOI). However, these CO2 emissions can only show its value during operation phase of ship life. In order to evaluate the effect of CO2 emissions during ship building, maintenance, and scrapping on energy efficiency, a real time EEOI definition was put forward, a life cycle assessment (LCA) calculation framework was established, and a ship propulsion model with main diesel engine was built. A bulker carrier YUMING was taken as the case ship. CO2 emissions during ship building, maintenance, and scrapping were calculated. Main engine revolution and real time EEOI value with other parameters were obtained by simulating in different ship draft. The results show that life cycle assessment result will explicitly increase the real time EEOI value especially in lower engine speed and lower ship draft. The engine revolution at the lowest EEOI value will increase explicitly by life cycle assessment result. It means that the lower limit of ship speed should increase during slow steaming. Therefore, slow steaming may bring less environmental benefit if the life cycle assessment result is involved.

Diel differences in blue whale (Balaenoptera musculus) dive behavior increase nighttime risk of ship strikes in northern Chilean Patagonia.

The northern Chilean Patagonia region is a key feeding ground and a nursing habitat in the southern hemisphere for blue whales (Balaenoptera musculus). From 2014 to 2019, during 6 separate research cruises, the dive behavior of 28 individual blue whales was investigated using bio‐logging tags (DTAGs), generating ≈190 h of data. Whales dove to significantly greater depths during the day compared to nighttime (day: 32.6 ± 18.7 m; night: 6.2 ± 2.7 m; P < 0.01). During the night, most time was spent close to the surface (86% ± 9.4%; P < 0.01) and at depths of less than 12 m. From 2016 to 2019, active acoustics (scientific echosounders) were used to record prey (euphausiids) density and distribution simultaneously with whale diving data. Tagged whales appeared to perform dives relative to the vertical migration of prey during the day. The association between diurnal prey migration and shallow nighttime dive behavior suggests that blue whales are at increased risk of ship collisions during periods of darkness since the estimated maximum ship draft of vessels operating in the region is also ≈12 m. In recent decades, northern Chilean Patagonia has seen a large increase in marine traffic due to a boom in salmon aquaculture and the passenger ship industry. Vessel strike risks for large whales are likely underestimated in this region. Results reported in this study may be valuable for policy and mitigation decisions regarding conservation of the endangered blue whale.

METHOD OF DETERMINING EFFICIENCY DURING IMPLEMENTATION OF INSTRUMENTS FOR ACCURATE MEASUREMENT OF SHIP DRAUGHT

The article justifies the relevance of improving the accuracy of determining the weight of cargo by draught of a vessel in order to increase the economic efficiency of the operation of ships. The authors propose to install remote draught meters on ships, and offer efficiency calculations for the introduction of devices for measuring the draught of ships and their application in practice. The analysis showed that, using traditional methods of draught determination, there is a very significant measurement error that negatively affects the quality of transportation and the reliability of determining the mass of the cargo. The authors present the methodology for determining the economic efficiency of ship equipment with remote draught meters. On test cases, performed for the conditions of transportation of various cargoes on specific lines, the expected efficiency of using remote precipitation gauges is shown in comparison with traditional methods for determining the ship's draft. According to the results obtained, the payback of the installation of draught meters on ships for low tariff cargoes occurs during five voyages, for more expensive and high tariff cargoes during the first voyage.

Navigation Ship's Drift Angle Determination Method in Curved Channel

Ai, W. and Zhu, P., 2020. Navigation ship's drift angle determination method in curved channel. In: Wan, Z. (ed.), Coordinated Sustainable Development in Coastal Areas: Environment and Economy. Journal of Coastal Research, Special Issue No. 109, pp. 181–184. Coconut Creek (Florida), ISSN 0749-0208.Ship's drift angle is closely related to ship's navigation safety and channel's dimension design in curved channel. It is important to study ship's drift angle in order to ensure ship's safety when passing curved channel. In this paper, ship's navigation drift angle in curved channel is researched. The results of research show that ship's navigation drift angle is closely related to channel's radius, water depth, curved channel's longitudinal current velocity, ship's draft and ship's speed. The drift angle calculation equation is also put forward in this paper.