Optimum Ship Routing Research Articles

Statistical analysis of waves’ effects on ship navigation using high-resolution numerical wave simulation and shipboard measurements

The analysis of ocean surface waves is essential to ensure safe navigation. Since 2010, different on-board observation data from bulk carriers, including those navigating high-risk shipping regions in the southern hemisphere with strong ocean currents, have been collected for 6 years. High-resolution numerical simulations of ocean waves for four rough sea cases, considering the effect of wave-current interaction on ship navigation, have been performed using the WAVEWATCH III model. The simulations considered the ocean surface wind force from the widely used reanalysis database of the National Centers for Environmental Prediction Final and European Center for Medium-range Weather Forecasts Interim Reanalysis. To provide practical suggestions for safe navigation by avoiding possible high-risk ocean regions and construct a more effective and efficient optimum ship routing system, the model results were validated based on on-board observations, followed by discussions on the responses of ship motion and navigation to sea states at different levels. Finally, early warning criteria, including various operational ocean parameters for ballast and loaded ships sailing in rough seas were identified.

Comparative assessment of NCEP and ECMWF global datasets and numerical approaches on rough sea ship navigation based on numerical simulation and shipboard measurements

Long-term shipboard measurements of vessel performance in actual seas and practical guidance for proper ship operations in rough sea conditions are of great importance for a safe, economical and environment-friendly optimum ship routing. Data was collected from a bulk carrier during 2010–2016 covering both the Southern and Northern Hemispheres with high seasonal variability. Using the meteorological and wave models, the Weather Research and Forecasting Model (WRF) and WAVEWATCH III (WW3), numerical simulations of the weather and sea state were conducted for eight rough sea cases using the grid point value (GPV) datasets NCEP-FNL and ERA-Interim. Model results were validated by shipboard measurements and ship motion calculations. Results show a better performance of NCEP-FNL on generating high ocean surface wind speed of heavy weather than that of the ERA-Interim, while the ERA-Interim tends to perform better for generation of wind direction. Besides, utilization of a high-resolution WRF model tends to increase the accuracy of wind simulations for extremely high and low wind speed cases when compared to the linear interpolation of GPV datasets, which tends to perform better for relatively modest wind speed conditions. Results also suggest that, to achieve an optimum ship routing considering safety, cost and emission reduction; it should use the high-resolution WRF model with NCEP-FNL initial and boundary conditions to generate ocean surface winds, followed by the WW3 wave model to generate ocean surface waves for the most accurate performance in heavy weather.

Comparative study on WRF model simulations from the viewpoint of optimum ship routing

In addition to other studies focused on the WRF performance of rainfall, temperature, and precipitation, the present study provides practical suggestions for ship operators on choosing grid point value (GPV) datasets and WRF modeling approaches to help make better decisions on weather routing by estimating strong wind with a higher accuracy. Two different GPV datasets, the NCEP-FNL and ERA-Interim, are used for WRF modeling. Various modeling approaches, which include applying different physics options and choosing whether to adopt the four-dimensional-data-assimilation, are employed for numerical simulation. Then, on-board measurements of a bulk carrier has been used to validate the calculated wind of eight rough-sea navigational cases. This occurs over a wide spatial range, covering ocean regions such as the Northwest Pacific Ocean, South of Australia, Tasman Sea, Southeast of Africa, and Southeast of America, as well as a wide temporal range of four years. Results of 64 WRF simulations show that ERA-Interim is suitable for longer periods, while NCEP-FNL can analyze extremely high winds. Additionally, grid nudging can also reduce the wind strength due to its smoothing effect. Finally, selections of these different GPV datasets and modeling approaches for ship weather routing are discussed, particularly for rough-sea navigations.

A Three-Dimensional Dijkstra's algorithm for multi-objective ship voyage optimization

In this paper, a Three-Dimensional Dijkstra's optimization algorithm is proposed to allow a ship to plan her waypoints and sailing speeds along each waypoint. It is expected to generate global optimum solutions for ship routes. Its capability of fuel saving as objectives is demonstrated by comparing its results with those obtained from other conventional voyage optimization algorithms, and the actual fuel consumption of a container ship with full-scale measurements. The proposed Three-Dimensional Dijkstra's algorithm can generate global optimum ship routing encountering less harsh sea environment, leading to at least 5% reduction of fuel consumption within the analysed cases. Furthermore, it can perform multi-objective voyage optimization, such as minimum fuel, minimum damage accumulation, lowest crack propagation, etc., with accurate ETA in the planning process.

Application of wave model for weather routing of ships in the North Indian Ocean

Weather routing of ships is used to establish the shortest time route or the most economical route from a departure to arrival point by applying available information of the weather condition viz. wind, wave and current. Information on ship speed loss due to these effects is pre-computed using sea-keeping computing tools, which are then suitably employed in the optimum ship routing algorithm. This developed algorithm was investigated using the wave height information from GEOSAT altimeter records. Dijkstra’s path optimization scheme, which employs optimal control theory and dynamic programming technique, is used to obtain reliable optimum route in a given random sea-state.

Complete Identification of the Roll Equation Using the Stationary Random Roll Response

A method is developed to predict the time series of the wave exciting moment per unit virtual mass moment of inertia using the stationary random roll response. The estimated variance and autocorrelation function of the excitation are compared with those obtained using numerically generated data. The agreement is excellent. The method was also applied to experimental data obtained using two ship models. The predicted autocorrelation function for the excitation was compared with the autocorrelation function of the wave height. The method predicts the form of the autocorrelation function accurately. The method lends itself to use aboard ships at sea without interrupting the mission of the ship. Results of this analysis can help in planning optimum ship routing.

荒天下での水面上巨大構造船の定常航行性能

The steady-state cruising performance of a large passenger ship and a PCC under heavy wind and waves are presented in this paper. These kinds of ships have specifications with very large hull and superstructures above sea level. Strong wind causes large drift, heel and rudder angles to ships and exerts great influence on the ships' cruising performance. From safety and economical aspects the assessment of added resistance under such wind and wave loadings is very important for those ships. Formulation of the steady-state equations is based on the MMG model for a ship manoeuvring simulation to obtain the steady ship condition. The wind and wave loads on the ships are calculated using the latest methods proposed by the authors. From this analysis, the special specifications of the steady condition for the large passenger ship and the PCC are clearly understood. Moreover, speed loss and DHP increase of those ships in the sea around Japan are revealed in this paper. It is cleared in the calculated results that wind effect has a very important role for the ships with large superstructures. Finally using the results of steady-state cruising performances, the optimum ship routing in wind and waves is presented by the dynamic programming method in order to find the route for reducing the navigating time of the ships.

ウェザー・ルーティング・サービスの利用 : 船社における利用の実態( 最適航法)

ウェザー・ルーティング・サービスの利用 : 船社における利用の実態( 最適航法)

Meteorologie im dienste der schiffahrt

After giving a brief historical review on the discovery of ocean wind systems, the kinds and benefits of marine weather forecasts, storm warning services, and storm flood services are explained. The activities and effects of ship-borne weather services are described. A major use of meteorological material is made in navigation, and optimum ship routing methods are generally descussed. Ice accretion may cause severe danger to ships and is a main navigational hazard. Cold ocean currents, upwelling areas, and zones of rapid changes of air temperature are fields of danger for cargo in ships. Techniques for avoiding such risks are discussed. Finally, observations at sea, the basis of all marine meteorological work, are discussed.

31.—Development of Methods for Optimum Ship Routing

AbstractThroughout this paper optimum ship routing will mean the route, optimum from the viewpoint of a criterion, such as minimum crossing time ensuring the greatest possible safety, fuel saving, etc.The term ‘method of choice’ can be interpreted in two ways. On the one hand, it includes the amount of data (and the form of their representation) on the basis of which the choice is made. On the other hand, it implies the instruments used, whether it be intuition or strict mathematical calculations.The term 'method of choice' can be interpreted in two ways. On the one hand, it includes the amount of data (and the form of their representation) on the basis of which the choice is made. On the other hand, it implies the instruments used, whether it be intuition or strict mathematical calculations.

最適航法の基礎研究-V(日本航海学会第38回講演会)

There are some pulse-like disturbances in solving the optimum ship routing. Then, the writer showed the algorithm to get a solution in such situations using the art of dynamic programming.

Prediction of Wave Characteristics Over the North Atlantic

This paper develops a method for the prediction of wave height, period and direction on a 200-mile grid over the North Atlantic Ocean, using a wave spectrum technique. The method could be useful in conjunction with optimum ship routing across the ocean.AS discussed recently by Hanssen and James, ship routing across the ocean, using the optimum route with respect to weather conditions, is now becoming a practical possibility. One essential requirement is to predict the wave heights and lengths over all parts of the area concerned. This would require first, of course, a forecast of the wind conditions. At present the Meteorological Office issues prognostic weather charts 24 hours ahead and wave predictions must be tied to them. Wave conditions are not determined instantaneously by the weather conditions at a given time, but tend to be an integration of the weather conditions over two, three, or even more days before and so wave predictions 24 hours ahead are likely to be more accurate than the wind forecasts.

Optimum Ship Routing

The paper describes the system developed and used by the United States Hydrographic Office for selecting the optimum track for transoceanic crossings by applying long-range predictions of wind, waves and currents to a knowledge of how the routed vessel reacts to these variables. Over a period of two years, over 1000 optimum ship routes were provided to one authority, with an average reduction in travel time of 14 hours.