. A method is presented for the evaluation of the exhaust emissions of marine traffic, based on the messages provided by the Automatic Identification System (AIS), which enable the positioning of ship emissions with a high spatial resolution (typically a few tens of metres). The model also takes into account the detailed technical data of each individual vessel. The previously developed model was applicable for evaluating the emissions of NOx, SOx and CO2. This paper addresses a substantial extension of the modelling system, to allow also for the mass-based emissions of particulate matter (PM) and carbon monoxide (CO). The presented Ship Traffic Emissions Assessment Model (STEAM2) allows for the influences of accurate travel routes and ship speed, engine load, fuel sulphur content, multiengine setups, abatement methods and waves. We address in particular the modeling of the influence on the emissions of both engine load and the sulphur content of the fuel. The presented methodology can be used to evaluate the total PM emissions, and those of organic carbon, elemental carbon, ash and hydrated sulphate. We have evaluated the performance of the extended model against available experimental data on engine power, fuel consumption and the composition-resolved emissions of PM. We have also compared the annually averaged emission values with those of the corresponding EMEP inventory, As example results, the geographical distributions of the emissions of PM and CO are presented for the marine regions of the Baltic Sea surrounding the Danish Straits.

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Extension of an assessment model of ship traffic exhaust emissions for particulate matter and carbon monoxide

Development of a Ship Weather Routing System

During the voyage, predicting fuel consumption of ships under different sea-states and weather conditions has been a challenging and far-reaching topic, because there are a great number of feature variables affecting the fuel consumption, including main-engine status, cargo weight, ship draft, sea-states and weather conditions, etc. Data driven statistical models have been employed to model the relationship between fuel consumption rate and these voyage parameters. However, some of the feature variables are highly correlated, e.g. wind speed and wave height, air pressure and wind force, cargo weight and draft etc., thus a typical multiple collinearity problem arises so that the fuel consumption cannot be accurately calculated by using the traditional multiple linear regression. In this study, the LASSO (Least Absolute Shrinkage and Selection Operator) regression algorithm is employed to implement the variable selection for these feature variables, additionally, it guides the trained predictor towards a generalizable solution, thereby improving the interpretability and accuracy of the model. On the basis of the LASSO, a novel ship fuel consumption prediction model is proposed. Experimentally, the superiority of the proposed method was confirmed by comparing it with some existing methods on predicting the fuel consumption. The proposed method is a promising development that improves the calculation of the fuel consumption.

Predicting ship fuel consumption based on LASSO regression

A semi-empirical ship operational performance prediction model for voyage optimization towards energy efficient shipping

The behavior of a ship in regular waves during maneuvering was studied by using a two-time scale model. The maneuvering analysis was based on Soding’s (Schiffstechnik 1982; 29:3–29) nonlinear slender-body theory generalized to account for heel. Forces and moments due to rudder, propeller, and viscous cross-flow follow from the state-of-the-art procedures. The developed unified theory of seakeeping and maneuvering was verified and validated for calm water by comparing it with experimental and calculated zigzag and circle maneuvers. Linear wave-induced motions and loads were determined by generalizing the Salvesen-Tuck-Faltinsen (Trans SNAME 1970; 78:250–287) strip theory. The mean second-order wave loads in incident regular deep water waves in oblique sea conditions were estimated by the potential flow theories of Faltinsen et al. (Proc 13th Symp Naval Hydrody 1980), Salvesen (Proc Intl Symp Dynam Mar Vehicl Struct Wave 1974), and Loukakis and Sclavounos (J Ship Res 1978; 22:1–19). The considered theories cover the whole range of important wavelengths. Comparisons between the different mean second-order wave load theories and available experimental data were carried out for different ship hull forms when the ship was advancing forward on a straight course. The mentioned methods have been incorporated into the maneuvering model. Their applicability from the perspective of the maneuvering ability of the selected types of ships was investigated in given wave environments. The wave conditions are valid for realistic maneuvering cases in open coastal areas. It was demonstrated that the incident waves may have an important influence on the maneuvering behavior of a ship. The added resistance, mean second-order transverse force, and yaw moment also play important roles.

A unified seakeeping and maneuvering analysis of ships in regular waves

In an earlier publication, a statistical method was presented for the determination of the required propulsive power at the initial design stage of a ship. This method was developed through a regression analysis of random model experiments and full-scale data, available at the Netherlands Ship Model Basin. Because the accuracy of the method was reported to he insufficient when unconventional combinations of main parameters were used, an attempt is made in the present article to extend the method by adjusting the original numerical prediction model to test data obtained in some specific cases. This adaptation of the method has resulted in a set of prediction formulae with a wider range of application. Nevertheless, it is pointed out that the given modifications have a tentative character only, because the adjustments are based on a small number of experiments. In any case, the application is limited to hull forms resembling the average ship described by the main dimensions and form coefficients used in the method. The extension of the method was focused on improving the power prediction for high-block ships with low L/B ratios, and for slender naval ships with complex appendage arrangements and immersed transom sterns.

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An approximate power prediction method

This paper presents revised formulae for statistical power prediction based on a greater number of results than the original equations reported in a previous paper which comprised a numerical representation of resistance properties and propulsion factors that could be used for statistical ship performance prediction. Following over a year of experience, several fields for improvement of the derived prediction methods given before are indicated, namely: The formula for wavemaking resistance does not include the influence of the bulbous bow. The resistance of ships with large bulbous bows is overestimated by the original formula. The wavemaking resistance of ships with a large waterplane-area coefficient is overestimated by the previous formula. The accuracy of the formula for the thrust-deduction fraction for a slender single-screw ship appeared to be insufficient. The wake fraction and the model/ship correlation were not properly represented by the formula for full ships at ballast draught. Order from BSRA as No. 49,917.

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G.G.J. Mennen

Papers

An approximate power prediction method

A statistical power prediction method