Single Ships Research Articles

Fuzzy logic-based modeling method for regional multi-ship collision risk assessment considering impacts of ship crossing angle and navigational environment

The ship crossing angle and navigational environment have significant impact on the precisely modeling of regional ship collision risk, but the existed studies seldom consider this problem. In order to realize the perception of regional multi-ship collision risk, this paper proposes a fuzzy logic-based modelling method for regional multi-ship collision risk assessment considering impact of ship crossing angle and navigational environment. The method incorporates the impact factors of DCPA, TCPA, ship crossing angle and navigational environment in multi-ship encounter situation by using fuzzy logic theory. We use Analytic Hierarchy Process (AHP) to obtain the risk weights of different ships versus single ships, and then obtain the value of multi-ship collision risk. In order to verify the validity of the model, data from the Taiwan Strait is used for verification, and the results show that this method can realize the early warning of regional multi-ship collision risk. The method can provide an important basis for maritime collision risk monitoring and ship navigation risk assessment for maritime administration departments and shore-based center of maritime autonomous ships.

Mathematical Model for Solving Problem of Target Allocation of Antiaircraft Fire Weapons in AD Contour of Surface Ship (in AD System of Group of Ships) in Case of Attack Threat and Repelling Attacks of Anti-Ship Cruise Missiles

The improvement of the algorithms of processing information and controlling of weapons systems in combination with their automation, which can significantly reduce time from the moment of detection of air targets to their destruction, is a promising direction in organizing of building and effective combat use of such complex systems as the contour of antiaircraft defense (AD) of a single surface ship and the AD system of a group of the surface ships. The transition to the creation and use of the precision-guided long-range munition, e.g. anti-ship missiles (AShM), allows to destroy ships from remote lines without entering the zone of the fighter aircraft action and reach of the antiaircraft missile system. When repelling attacks of anti-ship cruise missiles, a poor-quality solution of the problem of the target allocation of the antiaircraft fire weapons of a ship (group of ships) does not allow to realize the combat capabilities of the AD contour (system) as a whole, which leads to a loss of combat capability of the ship (ships). The main difference between the proposed mathematical model for solving the target allocation problem and those implemented in the combat information and controlling systems of the surface ships is the fact that it provides the possibility of evaluating own antiaircraft fire weapons and enemy’s AShM when developing an optimal target allocation plan based on a detailed account of the AShM detection range, coordination of the destruction zones, sectors of fire, lines of the implementation of the AShM tasks, mutual security measures, electromagnetic compatibility of the electronic means, i.e. taking into account the existing zones of the destruction of the antiaircraft fire weapons, as well as solving the problem of the target allocation in time. The solution of the task is carried out both directly during the antiaircraft combat, and in the case of the attack threat of the AShM. In its turn, the last one makes it possible to optimize building of the antiaircraft fire covering system and the AD system of both a single surface ship and the group of the surface ships as a whole, and to optimize the solution of the target allocation problem, in particular. The presented mathematical model and the algorithm and program developed on its basis can be recommended after appropriate modification for inclusion in both automated combat control systems and respectively combat information and control systems of connections of surface ships and single ships, that allows to solve the problem of the target allocation on a time scale close to real.

Control Optimization of Readiness Mode of Antiaircraft Fire Weapons in Antiaircraft Fire Covering System of Surface Ships Formation in Case of Attack Threat of Anti-Ship Cruise Missiles

Currently, the decisive factor in the development of the theory of military art in the sea is the fact of transition to the creation and use of precision-guided long-range munition by an enemy - anti-ship cruise missiles (ASCM), so that to destroy ships from remote lines without entering the zone of the fighter aircraft action and reach of the antiaircraft missile system. A promising direction in the organization of the building and effective combat use of such complex systems as the anti-aircraft defense contour of a single surface ship, and the anti-aircraft defense system of a group of surface ships in the threat of attack and repelling attacks of anti-ship cruise missiles, is the improvement of the algorithms for information processing and control of weapons systems in combination with their automation. Modern information technologies based on the use of computer technology and mathematical modeling allow improving the decision-making process in the tasks of building complex systems, processes of planning and organizing their activities. The methods of “artificial intelligence”, automation of the process of forces and means control in combat significantly increase the efficiency of decision-making. The fleeting nature and rapid change of the situation in anti-aircraft combat require solving the problem of repelling attacks by anti-ship cruise missiles in real time, that is impossible without full automation of the process of controlling the forces and means of anti-aircraft defense, in case of that human participation in anti-aircraft combat should be minimized, and completely excluded if possible. One of the complex systems that require full automation and real-time operation is the anti-aircraft fire covering system for surface ships formation. Determination of the optimal (expedient) combat readiness mode of the anti-aircraft fire weapons included in its composition is a prerequisite for the effective functioning of the anti-aircraft fire covering system in anti-aircraft combat. The article proposes a problem solution of the control optimization of the combat readiness mode of the anti-aircraft fire weapons in the anti-aircraft fire covering system of the surface ships formation in the case of the attacking threat of the anti-ship cruise missiles. The obtained results will substantiation of an optimal (expedient) mode of combat readiness and also creation of recommendations for setting the duty schedule of the anti-aircraft fire weapons in the interests of anti-aircraft defense. The presented mathematical model and the developed on its basis algorithm and program can be recommended for inclusion in both automated combat control systems and respectively combat information and control systems of connections of surface ships and single ships.

Characterizing ship-induced hydrodynamics in a heavy shipping traffic waterway via intensified field measurements

Ship-induced hydrodynamics play an important role in shaping the cross-sectional profile of inland waterways and produce a large amount of pressure on the fluvial environment. This study aimed at quantifying the characteristics of ship-induced waves and currents in a heavy shipping traffic waterway via intensified field measurements conducted in the Changzhou segment of the Grand Canal, in Jiangsu Province, China. Based on the processed hydrodynamic data, waves and currents caused by single ships and multiple ships were investigated. For single ships, the ship-induced wave heights estimated with empirical formulas were not consistent with the observations. Categorized by the loading conditions of barges, the drawdown height was characterized by the ratio of ship speed to its limit speed. The maximum non-dimensional ship-induced wave height was parameterized by a nonlinear combination of the depth Froude number and a blockage coefficient. For multiple ships, when ships closely followed each other or interlaced each other's paths, it was difficult to characterize the superposition of several ship wakes. The magnitudes of current velocities induced by single ships and multiple ships were respectively nine and six times as large as those of natural flow. This may result in more severe sediment (re)suspension than natural flows.

Effects of Hull and Control Surface Roughness on Ship Maneuvering

The effects of hull roughness on ship maneuvering characteristics are investigated. The hydrodynamic derivatives in the equations of motion for surface vessel maneuvering are modified to incorporate roughness of the hull and rudder. Vessel lifetime roughness profiles are postulated based on construction, coatings, operation, and maintenance for a vessel life of 25 years. These are then applied to the turning maneuver for single screw cargo ships with block coefficients from .60 to .80. The implications for naval missions are discussed. Introduction The effects of hull roughness, including fouling, are known to affect the performance of a vessel, especially as measured in additional fuel consumption and less so, the number of voyages in a lifetime. Today, there is significant attention given to hull surface cleaning, coating, and propeller polishing to address these issues. In addition and even less known are the effects on the maneuvering performance of a vessel. For naval vessels, they may affect the success of the mission. Roughness of the hull can occur because of a number of factors including hull material used and quality of construction, mechanical damage in operation, roughness from paints and coatings and their method of application, damage to the coating during maintenance, corrosion and pitting of the hull structure material, and biofouling influenced by the type of antifouling paint or coating and method of application. The roughness never ceases to increase during the vessel’s life. Starting with the hull material and construction, then the effects of different paints and coatings, operations, dry-docking intervals, and approach to maintenance, it is possible to develop a lifetime roughness profile.

A methodology for the design of an effective air quality monitoring network in port areas

The assessment of the impact of ship emissions is generally realised by a network of receptors at ground level inside the port area or in the nearby urban canopy. Another possibility is the use of dispersion models capable of providing maps of concentrations to the ground taking into account ship emissions and weather conditions. In this work traffic data of passengers ships in the port of Naples were used to estimate pollutant emissions starting from EMEP/EEA (European Environment Agency/European Monitoring and Evaluation Programme) methodology and real data of power engines. In this way, a hourly file of emission rates was produced and input to CALPUFF together with meteorological data. Then SO2 concentrations at different heights (0–60 m) in correspondence of selected points within the port area were evaluated. Results are compared with data measured at ground level in monitoring campaigns showing how is possible to better identify and quantify the air pollution from ships in port by positioning the receptors inside the port area at different heights from ground-level. The results obtained give useful information for designing an optimum on-site air quality monitoring network able to quantify the emissions of pollutants due to naval traffic and to individuate the contribution of single ships or ships’ categories.

Targeted CCUS R&D Activities in Industrial Clusters

Although initial CCUS demonstration projects are planned to commence as point-to-point projects, with a single pipeline or ships linking one source to one sink, the concept of ‘CCUS clusters’ is considered to be crucial to maximize the climate change mitigation potential of the technology. This work is part of ALIGN-CCUS, currently one of the largest European R&D projects on CCUS, with a work programme designed to enable the acceleration of CCUS in specific industrial regions in ERA-NET countries: Teesside and Grangemouth (UK), Rotterdam (NL), North Rhine-Westphalia (DE), Grenland (NO) and Oltenia (RO). The project will combine the results from each of these objectives to deliver actionable blueprints in each region, in which CCUS enables low-emission industries, through geological storage and/or utilization of CO2. Early work presented in this paper focuses primarily on development of CO2 supply profiles in the UK case study, a detailed CO2 emission inventory for North Rhine-Westphalia. An overview of work proposed in the other clusters is presented.

Vane-Turbine as an Energy Conversion in the Propeller Slipstream of Single Screw Ship

The screw propeller of a ship generates thrust to make it moving. As a propeller rotates, it draws fluid into itself from the surrounding area (slipstream). The propeller produces two types of flow behind it, accelerated and circulated flows. Some of the energy from the ship engine is lost in the accelerated flow behind ship as a jet wash.The kinetic energy losses in the slipstream propeller captured by a turbine called the propeller-turbine system. This composed screw propeller of a vessel (the main propeller) and a vane turbine that is the area of vanes located inside the wake of the main propeller. It recovers the energy generated by the main propeller pushing water back out (which would be otherwise wasted behind the main propeller) and hopefully enhancing the efficiency of the main propeller.The influence of vane turbine on the performance breakdown of single screw ships were analyzed by using 5 (five) ships . Ship powering was calculated by using DESP Code 10 software. Thrust and power of vane turbine were calculated by applying actuator disc theory. Although the vane turbine affected speed loss of the ship, the power efficiency gained to be found always positive. Vane turbine is suitable as an energy saving device of the single screw ship.

Ship‐Berth Link as Bulk Queueing System in Ports

The differing kinds of cargo ships with variable loads arrive in seaports and river ports. Single ships are predominant in seaports and they arrive with differing sizes of loads in some time periods. Moreover, these variable groups of loads require single service. However, in the river ports, the kinds of arriving cargo ships can be in the form of the single ships and in groups as pushed or pulled convoys or tows of barges. Also, every barge requires single service in a wharf or within a harbor. In both cases there is an analogy between the arrivals in variable groups of loads and the number of barges in convoys. Therefore, in this study, an analytical methodology, with the help of bulk queueing systems, to analyze and to plan berth requirements in the ports, is developed and convenient graphs are presented. Stated methodology may apply for determining the optimum number and the capacity of berths within seaports and river ports.

On the Flow Measurement in High Wake Region at the Propeller Plane

This paper describes the attempts made in Nagasaki Experimental Tank to improve the accuracy of flow measurement in high wake region of single screw ships. Noticing strong downward velocity in the high wake region preliminary approach was made by modifying analysis method with extension of calibration range and by inclining the probe towards flow direction. The results indicated that the normal use of a 5-hole pitot probe (set in horizontal direction) does not yield accurate data of downward velocity component.As a next step an 8-hole pitot probe was developed incorporating a 'normal' and an 'inclined' probe, and it proved to be convenient for measurement of the flow at the propeller plane.Effect of wake peak values on propeller vibratory forces is examined and significance of choosing accurate measurement data is discussed.