Weather Routing Research Articles

The influence of route choice and operating conditions on fuel consumption and CO2 emission of ships

The influence of various parameters, such as ship initial speed (full ahead and lower engine loads), loading condition, heading angle and weather conditions on ship fuel consumption and CO2 emission is presented. A reliable methodology for estimating the attainable ship speed, fuel consumption and CO2 emission in different sea states is described. The speed loss is calculated by taking into account the engine and propeller performance in actual seas as well as the mass inertia of the ship. The attainable ship speed is obtained as time series. Correlation of speed loss with sea states allows predictions of propulsive performance in actual seas. If the computation is used for weather routing purposes, values for various ship initial speed, loading conditions and heading angles for each realistic sea‐state must be provided. The voluntary speed loss is taken into account. The influence of the ship speed loss on various parameters such as fuel consumption and CO2 emissions is presented. To illustrate the presented concept, the ship speed and CO2 emissions in various routes of the Atlantic Ocean are calculated using representative environmental design data for the track of the routes where the ship will sail.

실시간 적응 A* 알고리즘과 기하학 프로그래밍을 이용한 선박 최적항로의 2단계 생성기법 연구

실시간 적응 A* 알고리즘과 기하학 프로그래밍을 이용한 선박 최적항로의 2단계 생성기법 연구

Evaluation of ship performance in international maritime transportation using an onboard measurement system - in case of a bulk carrier in international voyages

The present global society has made the development of a safe and efficient maritime transportation system more imperative than ever before. Of particular impetus is the steep rise in the price of crude oil, which has required shipping companies to minimize the fuel consumption of their ships. Moreover, the emission of carbon dioxide has been restricted by the EEDI (Energy Efficiency Design Index) issued by the IMO (International Maritime Organization). Weather routing services have become more important to shipping companies. However, there are accuracy deficiencies in the numerical models employed by such services for purposes such as weather forecast and the ship speed loss phenomenon. Moreover, the development of weather routing models has been hampered by insufficient accumulation of continuous data on ship motions, and the navigation, engine, and weather parameters. The data used for this study was collected over one year from a 20,000 DWT class bulk carrier on worldwide voyages. Some new relationships regarding ship motions, speed loss, and wave conditions were developed, which were verified by experimental data and numerical simulations of the frequency response of the ship motion and of the weather and ocean.

Two-phase approach to optimal weather routing using geometric programming

In this study, we propose a new approach for solving the weather routing problem with an efficient speed schedule that minimizes fuel consumption. The procedure used to solve the problem comprises two phases. The first phase aims to obtain the optimal route at each time step using the A* algorithm. During this phase, the speed of the ship is fixed and only the heading angle is optimized. The safety regulations published by IMO are applied as constraints during the first phase. The second phase is the speed scheduling phase. The original problem is highly nonlinear and nonconvex optimization problem and it can be converted into a geometric programming problem. By solving the geometric programming problem, we can determine the optimal speed schedule for the ship. The optimal speed obtained using this procedure guarantees the global optimum because the problem is convex. This method can produce an almost optimal solution to the weather routing problem more efficiently than existing methods.

An approach for development of a ship routing algorithm for application in the North Indian Ocean region

This paper presents a general approach for the development of a ship weather routing algorithm for determining optimal route which is taken here as the minimum-time route. The optimization model is based on a form of Dijkstra's algorithm. The developed algorithm is versatile and is capable of considering nearly all realistic practical constraints that a ship faces during her voyage. The ‘weight’ functions and the routes are determined by considering both involuntary and voluntary speed reduction. The algorithm is investigated using various realistic wave data for the North Indian Ocean region obtained from a 3rd generation WAM model. Illustrative examples of minimum-time sea routes on Arabian Sea and Bay-of-Bengal have been determined and presented to demonstrate the capability of the algorithm in handling many practical constraints within its framework.

Operation of ULCS - real life

In this paper the real life operation of ULCS (Ultra Large Container Ships) is presented from the point of view of shipmasters. The paper provides interpretation of results of questionnaire filled by masters of large container ships during Tools for Ultra Large Container Ships (TULC) EUI FP7 project. This is done in a way that results of questionnaire are further reviewed and commented by experienced master of ULCS. Following phenomena are subject of questionnaire and further discussed in the paper: parametric rolling, slamming, whipping, springing, green water and rogue waves. Special attention is given to the definition of rough sea states as well as to measures that ship masters take to avoid them as well as to the manoeuvring in heavy seas. The role of the wave forecast and weather routing software is also discussed.

A comparative study of deterministic and ensemble weather forecasts for weather routing

This paper presents and discusses the results of a comparison between using deterministic and ensemble weather forecasts for weather routing. The study is based on comparisons between predicted and realised performance of routes suggested by a route optimization method and focuses on two important performance factors, namely, fuel consumption and late arrival. The study is purely qualitative since the simulations do not include re-routing of the vessel as new forecasts become available. To perform the study a multi-objective dynamic programming method is tailored to the problem and implemented to perform the route optimization and a ship performance model is used to calculate the additional fuel consumption due to wind and waves acting on the ship. The results show that route optimization using ensemble weather forecasts has the potential to reduce the risk of late arrival for voyages during periods of harsh weather.

Multi-objective Weather Routing with Customised Criteria and Constraints

The paper presents a weather routing algorithm utilising a multi-objective optimisation with constraints, namely the Multi-objective Evolutionary Weather Routing Algorithm (MEWRA). In the proposed approach weather route recommendations can be made simultaneously e.g. for passage time, fuel consumption and safety of passage by means of Pareto optimisation. The sets of criteria and constraints in the optimisation process are fully customisable. The algorithm handles static (time-independent) and dynamic (time-dependent) constraints e.g. forecasted high wind speed regions or customisable areas to be excluded from routing (e.g. due to piracy). The paper includes a description of MEWRA as well as examples of its usage for finding Pareto-optimal transoceanic ship routes.

Reducing Ship Emissions: A Review of Potential Practical Improvements in the Propulsive Efficiency of Future Ships

Environmental issues such as the emission of greenhouse gases, pollution, wash and noise are having an increasing impact on the design and operation of ships. These environmental issues together with economic factors, such as rising fuel costs, all ultimately lead to the need to minimise ship propulsive power. Various methods and devices for reducing propulsive power are reviewed and discussed. The most favourable methods, from a feasible and practical point of view, are identified and quantified. It is found that potential reductions in the resistance of existing good hull forms are relatively small, but optimising hull-propeller-rudder interaction offers very promising prospects for improvement. The biggest potential savings in power arise from optimised operational strategies such as the use of optimum trim, speed and weather routing. Potential conflicts of interest when considering both economic and environmental requirements are investigated and discussed. Suitable design methodologies and procedures, taking into account economic and environmental factors, are suggested for the design of future ships.

Global distribution and risk to shipping of very extreme sea states (VESS)

ABSTRACTThe impact of extreme sea states on offshore infrastructure is of intense interest in the ocean engineering community at the present time. In this study, a new quality‐controlled database of global satellite‐derived estimates of significant wave height (HS) and surface marine wind speed from seven missions spanning the period August 1991–March 2010, known as GlobWave, is scanned to yield over 5000 ocean basin specific orbit segments with peak HS > 12 m. This population was subsequently distilled to a population of 120 individual storms [so‐called very extreme sea states (VESS) storms], in which there was at least one altimeter estimate of HS > 16 m. The highest HSs were observed in the Northern Hemisphere with ten orbit segments in the North Atlantic Ocean (NAO) with a peak HS of >18 m followed by four segments in the North Pacific Ocean (NPO). Only three HS peaks >18 m were seen in the entire Southern Oceans. Three of the >5000 orbit segments had a peak HS >20 m with the highest at 20.6 m. The number of VESS storms detected is greatest in the NAO (the smallest basin), a result that appears to be consistent with general circulation studies of extratropical cyclogenesis frequency and intensity in general atmospheric circulation models.A new continuous 33‐year global wave hindcast (GROW2012) based on a new atmospheric reanalysis wind field product appears to provide unbiased estimates of the probability of exceedance of VESS in extratropical storms and small‐basin dependent biases (0.5–1.5 m) of peak HS greater than ∼16 m. GROW2012 was, therefore, applied with a voyage simulator for nine trade routes to assess the risk of a merchant vessel that does not avail itself of weather routing of encountering VESS. The highest monthly exceedance probabilities (MEPs) at the VESS threshold of 14 m are found in the NAO and NPO at ∼0.1% during winter months. The alternative statistical distribution of the MEP of the single maximum peak sea state to be expected for a voyage for any month (MEPm) shows that the highest MEPm is for the month of December in the NAO along the great circle route between the middle US East Coast and entrance to English Channel and in the NPO along the Yokohama–Seattle route, at about 3%. Still, the overall probability of a vessel encountering sea states that may contain waves capable of catastrophic damage over a 33‐year lifetime is quite small with mean number of hours of exposure to a vessel typically less than ∼3 h for six of the nine routes and a maximum of 10 h for two of the routes.

해상환경을 고려한 선박항로의 최적화 시나리오 비교분석

Weather routing of a ship provides an optimal route to the destination by using minimal time or fuel in a given sea condition. These days, weather routing came into a spotlight with soaring fuel price and the environmental regulations of IMO and several countries. This study presents three scenarios of voyaging strategies for a ship and compared them in terms of the fuel consumption. The first strategy fixes the speed of a ship as a constant value for entire sailing course, the second fixes the RPM of the ship as constant for entire course, and the third determines the RPMs of the ship for each segment of the course. For each strategy, a ship route is optimized by using the A* search method. Wind, ocean current and wave are considered as ocean environment factors when seeking the optimal routes. Based on 7000 TEU container ship’s sea trial records, simulation has been conducted for three scenarios, and the most efficient routing scenario is determined in the view of fuel consumption.

フリートマネージメントにおける運航支援の研究

The author has promoted and implemented the research and development of the eco-friendly electric propulsion ship “Super Eco-Ship”, weather routing for domestic vessels “Navigation Support System”, and ship allocation problem “Ship scheduling support system” from the viewpoint of operational support of domestic shipping. In other words, the following steps were taken to improve vessel operation efficiency. First, build a highly efficient vessel by adopting the latest technology and having it operated by a great master. Then, optimally allocate vessels to meet the shipper’s requests and perform effective fleet management to achieve environmental and economic benefits. Although there are other tasks such posting crew assignments or vessel maintenance, NMRI takes the viewpoint of operational support technology. This paper introduces the history on Research & Development of operational support technology for fleet-management including the evaluation methodology of transportation fleets. These technologies are expected to find application not only in coastal shipping but also in ocean going shipping.

自動計測運航データを活用したウェザールティングサービス

自動計測運航データを活用したウェザールティングサービス

ウェザー・ルーティングについて

ウェザー・ルーティングについて

ウェザールーティングシステムの構築に関する研究-II.-船載型モニタリングシステムデータの活用-

In recent years, as a measure to reduce the effect of global warming caused by the maritime transport, vessels have been strongly advised to reduce fuel consumption. Weather Routing (WR) is a relatively inexpensive and easy way to implement the solution. However, for good operation, WR requires a good estimate of the vessel's propulsive performance at seas. In previous studies, it had been shown that ship's performance can be estimated by analyzing abstract logbook data. In this paper, the authors proposed a method for estimating the vessel's propulsive performance using thrust data obtained from an onboard monitoring system and using several possible parameterable methods. For carrying out the study, an Onboard Monitoring System was fitted onboard a 4,430TEU container ship for data collection. A minute examination of the collected data showed a clear relation between ocean wave state and thrust. A set of formulas was established to calculate the thrust increase relying on wave height and direction. The obtained equation allowed the authors to reconstruct an actual voyage within a 3% margin of error, showing the good performance of the proposed estimation method. WR simulations showed also the potential reduction of fuel consumption reduction achievable using the estimated vessel performances.

ウェザールーティングにおける太陽光エネルギー利用に関する基礎研究

In maritime society, the technical development for utilizing natural energy, such as solar power or wind force, is progressing. And in order to use solar energy safely and efficiently, it is necessary to develop weather routing technology. In this study, the authors examined the possibility of weather routing for ships using solar energy. First, on several routes of the ocean, the authors investigate the seasonal variation of a total solar power and the relation between route and solar power. This paper proposes the modified route selecting method to increase the total solar power for solar power ships.

Multicriteria Evolutionary Weather Routing Algorithm in Practice

The Multicriteria Evolutionary Weather Routing Algorithm (MEWRA) has already been introduced by the author on earlier TransNav 2009 and 2011 conferences with a focus on theoretical application to a hybrid-propulsion or motor-driven ship. This paper addresses the topic of possible practical weather routing applications of MEWRA. In the paper some practical advantages of utilizing Pareto front as a result of multicriteria optimization in case of route finding are described. The paper describes the notion of Pareto-optimality of routes along with a simplified, easy to follow example. It also discusses a choice of the most suitable ranking method for MEWRA (a comparison between Fuzzy TOPSIS and Zero Unitarization Method is presented). In addition to that the paper briefly outlines a commercial application of MEWRA.

A Study on the Propulsion Performance in the Actual Sea by means of Full-scale Experiments

The International Maritime Organization (IMO) has adopted Energy Efficiency Design Index (EEDI), Ship Energy Efficiency Management Plan (SEEMP) and Energy Efficiency Operational Indicator (EEOI) in order to reduce greenhouse gas (GHG) emissions from international shipping. And, the shipping industry is required to develop and improve the energy saving ship operation technologies to meet the above IMO guideline. The weather routing is one of the energy saving navigation technologies and widely adopted by oceangoing merchant ships. The effectiveness of the weather routing mainly depends on the accuracy of weather forecast data and the ship’s propulsion performance prediction. The propulsion performance in the actual sea is usually predicted using the Self Propulsion Factors obtained by model tests. It is necessary to understand the propulsion performance characteristics in the actual sea conditions for the improvement of propulsion performance prediction. From the above points of view, the authors performed full-scale experiments using a training ship in order to investigate the propulsion performance characteristics in the actual sea. This paper describes the analysis results on the characteristics of Power Curves and Self Propulsion Factors under various weather and sea conditions.

アンサンブル予報を用いたウェザールーティングの実用性について

アンサンブル予報を用いたウェザールーティングの実用性について

予測バイアス除去手法がウェザールーティングの精度におよぼす影響に関する研究

予測バイアス除去手法がウェザールーティングの精度におよぼす影響に関する研究