Simulation of ship handling in reverse

One of the main problems of seamanship is steering the boat in reverse modes. This skill can be achieved using simulators or simulators that work based on a mathematical model. This model should adequately describe all ship maneuvers, including simulation in reverse modes. The article deals with the mathematical modeling of maneuvering from a ship in reverse. The authors performed model calculations, basic test maneuvers, such as “Circulation”, “Exit Circulation” and “Zigzag”. The analysis of trajectories testifies to the qualitative correspondence of the calculation results according to the mathematical model to the practice of navigation, and this model can be used for automatic control of the vessel, for assessing the movement of the vessel in reverse, and teaching navigation skills on simulators and simulators. The vessel when moving in reverse, at low speeds obeys the steering organ, but at speeds greater than the average stroke on the backward shift, it leaves the circulation very slowly and sometimes becomes uncontrollable. The withdrawal of a reverse circulation vessel is extremely difficult and requires additional skills and abilities from the navigator.

The Method to Decrease Emissions from Ships in Port Areas

Nowadays great attention is being paid to the ecological aspects of maritime transport functioning, including the problem of pollution and emission of poisonous substances from ships. Such emissions have a significant impact on the environment and sustainable operation of ports, especially those located close to intensive waterways. A decrease in emissions from ships may be achieved by implementing different methods, among others, through the use of environmentally friendly fuels, electrical and hybrid vehicles, as well as through the improvement of port approach and inside navigational channels, optimization of the transport processes organization, etc. However, the size of the influence of ships’ crew and ports pilots’ qualification on the possibility to decrease the emissions from ships during maneuvering in port areas remains a question. This article aims to develop a method to assess the possible decrease of the emissions from ships in ports, considering human factor influence. The method has been developed and verified on the selected case study example. The influence of ships’ crew and ports pilots’ qualification on time spent on maneuvering operations by ships in port areas and consequently the volume of emissions has been investigated. The research results show that for the set conditions it is possible to reduce emissions from ships up to 12.5%. For that reason, appropriate education and training are needed to improve the qualifications of decision-makers performing ship maneuvers at ports areas.

Human Reliability Analysis of Ship Maneuvers in Harbor Areas

During a ship life cycle, one of the most critical phases in terms of safety refers to harbor maneuvers, which take place in restricted and congested waters, leading to higher collision and grounding risks in comparison to open sea navigation. In this scenario, a single accident may stop the harbor's traffic as well as incur in patrimonial damage, environmental pollution, human casualties, and reputation losses. In order to support the vessel's captain during the maneuver, local experienced maritime pilots stay on board coordinating the ship navigation while in restricted waters. Aiming to assess the main factors contributing to human errors in pilot-assisted harbor ship maneuvers, this work proposes a Bayesian network model for human reliability analysis (HRA), supported by a prospective human performance model for quantification. The novelty of this work resides into two aspects: (a) incorporation of harbor specific conditions for maritime navigation HRA, including the performance of ship's crew and maritime pilots and (b) the use of a prospective human performance model as an alternative to expert's opinion for quantification purposes. To illustrate the usage of the proposed methodology, this paper presents an analysis of the route keeping task along waterways, starting from the quantification of human error probabilities (HEP) and including the ranking of the main performance shaping factors that contribute to the HEP.

Navigators’ Behavior Analysis Using Data Mining

One of the ways to prevent accidents at sea is to detect risks caused by humans and to counteract them. These tasks can be executed through an analysis of ship maneuvers and the identification of behavior considered to be potentially dangerous, e.g., based on data obtained online from the automatic identification system (AIS). As a result, additional measures or actions can be taken, e.g., passing at a distance greater than previously planned. The detection of risks at sea requires a prior definition of behavior patterns and the criteria assigned to them. Each pattern represents a specific navigator’s safety profile. The criteria assigned to each pattern for the identification of the navigator’s safety profile were determined from previously recorded AIS data. Due to a large amount of data and their complex relationships, these authors have proposed to use data mining tools. This work continues previous research on this subject. The conducted analysis covered data recorded in simulation tests done by navigators. Typical ship encounter situations were included. Based on additional simulation data, the patterns of behavior were verified for the determination of a navigator’s safety profile. An example of using the presented method is given.

Human Reliability Analysis of Ship Maneuvers in Harbor Areas

During a ship life cycle, one of the most critical phases in terms of safety refers to harbor maneuvers, which take place in restricted and congested waters, leading to higher collision and grounding risks in comparison to open sea navigation. In this scenario, a single accident may stop the harbor’s traffic as well as incur into patrimonial damage, environmental pollution, human casualties and reputation losses. In order to support the vessel’s captain during the maneuver, local experienced maritime pilots stay on board coordinating the ship navigation while in restricted waters. Because of their shorter relative duration, harbor maneuvers accidents are more probable to occur due to human errors — reinforced by the inherent surrounding difficulties —, rather than machinery failures, for instance. The human errors are object of study of the human reliability analysis (HRA). Aiming to assess the main factors contributing to human errors in pilot-assisted harbor ship maneuvers, this work proposes a Bayesian network model for HRA, supported by a prospective human performance model for quantification. Similar works focus mainly on open sea navigation and collision accidents, which do not reflect the strict conditions found on port areas. Additionally, most of the models are highly dependent on expert’s opinion for quantification. Therefore, the novelty of this work resides into two aspects: a) incorporation of harbor specific conditions for maritime navigation HRA, including the performance of ship’s crew and maritime pilots; and b) the use of a prospective human performance model as an alternative to expert’s opinion for quantification purposes. To illustrate the usage of the proposed methodology, this paper presents an analysis of the route keeping task along waterways, starting from the quantification of human error probabilities (HEP) and including the ranking of the main external factors that contribute to the HEP.

Measurement of Speed Through Water

The relevant issue with monitoring and measuring ship performance is the measurement of speed through the water. In 2016 an ADCP was mounted on a US Navy ship for the purposes of a hull monitoring program. At the onset of the program a baseline trial was completed to both determine the clean hull performance of the ship and the performance of the ADCP on a surface ship. The trial included completing reciprocals using standard calculations and ’triangles’ using more advanced calculations to calculate speed through the water. The results from the ADCP, maneuvers, EMLog, and surface based HFRadar corrections are compared in this report and examined for agreement and repeatability. The ADCP performed successfully showing strong agreement and repeatability though strong concerns still exist for long term viability. The EMLog was found to have issues beyond calibration offsets. The surface based HFRadar appears to be a passable correction method that may be of more benefit for measurement of ship maneuvers. The new method for analyzing GPS/INS speed over the ground data presented in this report is shown to have good agreement with the ADCP with the added advantage over the classic calculation by generating an associated uncertainty with the speed.

Numerical and Experimental Investigations of Ship Maneuvers in Waves

Assuring a ship’s maneuverability under diverse conditions is a fundamental requirement for safe and economic ship operations. Considering the introduction of the Energy Efficiency Design Index (EEDI) for new ships and the related decreasing installed power on ships, the necessity arose to more accurately predict the maneuverability of ships in severe seas, strong winds, and confined waters. To address these issues, extensive experimental and numerical investigations were performed within the European funded Project SHOPERA. Here, second order forces and moments for a containership and a tanker were measured in model tests and computed by solving the Reynolds-Averaged Navier-Stokes (RANS) equations. Generally, these measured and computed second order loads (drift forces and yaw moments, added resistance) compared favorably. Furthermore, the effects of waves on zig-zag and turning circle maneuvers were investigated.