Vessel Speed Research Articles

Impacts of the Form Design and Operational Factors on the Energy Consumption of a Solar-Powered Boat: A System Dynamics Approach

This research paper aims to design a solar-powered boat and to analyze the effects of environmental and form-related factors on power consumption and battery duration by utilizing a system dynamics approach-based simulation. The boat form is designed as the planing hull and its hull resistance analysis was ensured in Maxsurf package program. PV panels having 548 W power output, and two battery packs with 4660 Wh capacity were placed on the hull body to employ an electrical motor having a 10 kW nominal power output. Two MPPTs were implemented in the system to increase solar system efficiency. The relationships between all system components were modeled in Vensim software to observe battery endurance changes under different conditions. Results demonstrated that the ideal vessel speed is calculated to be around 7 knots with roughly 8 hours of battery duration for the designed boat. 40% state of charge is a critical level for sailing, because 1.63 hours of cruising duration can be provided at 40% level while the speed is kept at 5 m/s (9.72 knots). Indeed, boat’s rising trim angle shorten the battery discharge time, thus navigation by no trim angle is the most effective usage for the vessel.

Estimating hidden fishing activity hotspots from vessel transmitted data

Monitoring fishery activity is essential for resource planning and guaranteeing fisheries sustainability. Large fishing vessels constantly and continuously communicate their positions via Automatic Identification System (AIS) or Vessel Monitoring Systems (VMSs). These systems can use radio or Global Positioning System (GPS) devices to transmit data. Processing and integrating these big data with other fisheries data allows for exploring the relations between socio-economic and ecosystem assets in marine areas, which is fundamental in fishery monitoring. In this context, estimating actual fishing activity from time series of AIS and VMS data would enhance the correct identification of fishing activity patterns and help assess regulations' effectiveness. However, these data might contain gaps because of technical issues such as limited coverage of the terrestrial receivers or saturated transmission bands. Other sources of data gaps are adverse meteorological conditions and voluntary switch-offs. Gaps may also include hidden (unreported) fishing activity whose quantification would improve actual fishing activity estimation. This paper presents a workflow for AIS/VMS big-data analysis that estimates potential unreported fishing activity hotspots in a marine area. The workflow uses a statistical spatial analysis over vessel speeds and coordinates and a multi-source data integration approach that can work on multiple areas and multiple analysis scales. Specifically, it (i) estimates fishing activity locations and rebuilds data gaps, (ii) estimates the potential unreported fishing hour distribution and the unreported-over-total ratio of fishing hours at a 0.01° spatial resolution, (iii) identifies potential unreported fishing activity hotspots, (iv) extracts the stocks involved in these hotspots (using global-scale repositories of stock and species observation data) and raises an alert about their possible endangered, threatened, and protected (ETP) status. The workflow is also a free-to-use Web Service running on an open science-compliant cloud computing platform with a Web Processing Service (WPS) standard interface, allowing efficient big data processing. As a study case, we focussed on the Adriatic Sea. We reconstructed the monthly reported and potential unreported trawling activity in 2019, using terrestrial AIS data with a 5-min sampling period, containing ~50 million records transmitted by ~1,600 vessels. The results highlight that the unreported fishing activity hotspots especially impacted Italian coasts and some forbidden and protected areas. The potential unreported activity involved 33 stocks, four of which were ETP species in the basin. The extracted information agreed with expert studies, and the estimated trawling patterns agreed with those produced by the Global Fishing Watch.

Domain-adapted feature transfer: A generalized framework for short-term vessel speed prediction

Data-driven methods have been in sight in ocean engineering for short-term vessel speed prediction. However, due to the requirements of large amounts of training data and the inevitable distributed inconsistency among datasets, they are not easy to generalize or achieve superior performance. Specifically, inadequate recorded data of newly in-serviced vessels and ever-changing met-ocean climates making it hard to fulfill an accurate prediction in practice, and it is tough to be improved by merely raising new data-driven models. Taking the case study of Valemax vessels, we uncover that the input–output features have significant differences between datasets, which impair the effectiveness of data-driven models in practical use. With the purpose of designing domain-invariant features for data-driven models, we propose a domain-adapted feature transfer (DAFT), a generalized strategy to narrow the differences of distribution between datasets, which can be combined with a variety of models to form a framework for short-term vessel speed prediction. The superiority and generalization of DAFT are demonstrated through detailed experiments with quantitative and qualitative analyses. In addition, its robustness when faced with insufficient data and the feasibility of using data from sister-ships are also clearly verified. Code is available at https://github.com/Ldiper/DAFT.

Bibliometric Review of Route Optimization in Maritime Transportation: Environmental Sustainability and Operational Efficiency

Route optimization in maritime transportation provides enormous cost saving and efficient resource allocation for companies. Shipping companies need to create an optimized route for shipping fleets. That is why route optimization has gained considerable and increasing attention in maritime transportation literature over the past few years. This research aims to identify the theoretical cornerstones, current research trends, and possible research avenues for future studies by reviewing 256 peer-reviewed route optimization articles in maritime transportation literature. For this purpose, first, theoretical cornerstones of route optimization in maritime transportation literature were examined by co-citation analysis and three clusters were identified: fleet routing and deployment; liner shipping rotation; and optimization of fuel consumption and vessel speeds. Second, current research trends of route optimization in maritime transportation literature were uncovered via bibliographic coupling analysis. The analysis results revealed that current research trends could be considered in four clusters: route planning; routing under different weather conditions; liner shipping network and service design; and environmental speed optimization. Finally, author-keyword analysis was performed to specify knowledge gaps and recommend future research areas.

Estimation of the spatiotemporal distribution of fish and fishing grounds from surveillance information using machine learning: The case of short mackerel (Rastrelliger brachysoma) in the Andaman Sea, Thailand

Rapid and accurate data gathering on fish catches and the geographical distribution of fishing activities is essential in fish stock assessments and fisheries management. Surveillance systems like the Vessel Monitoring System (VMS) have become popular globally, providing accurate data on fishing activities and fish abundance in near real-time. Our study demonstrates a procedure to find the best method in machine learning algorithms for detecting fishing operations from surveillance data. VMS data of 3,237 trips conducted by 91 purse seiners targeting short mackerel (Rastrelliger brachysoma) in Thai waters of the Andaman Sea during 2020 were used for the study. Twenty-five spatiotemporal, environmental, and fisheries-related parameters were investigated as predictors to detect and map the fishing activity. Eight algorithms were used to compare the model performance using cross-validation. The total catch per trip was reallocated to the predicted fishing locations of the trip from the best algorithms to depict the fishing ground. The results show that operation time and vessel speed are essential elements for determining the fishing operation of purse seiners. The most-relevant predictors are the calculated speed, operation time, and instantaneous speed. The Random Forest (RF) algorithm performed the best, with 86% accuracy, and therefore was used as the final model to detect the fishing operations. However, all reallocation approaches performed similarly well in depicting fish distribution. The allocation of catch data equally to the fishing position is recommended since it is the most straightforward technique. In contrast, reallocation catch using the RF algorithm prediction ratio for visualising the CPUE distribution achieved the best performance (with a slope of 1) compared with the training data. This study provides the first decent procedures for using surveillance information to detect and identify the prospective fishing operation of purse seiners—an approach that allows for a better understanding of short mackerel distribution. The proposed procedures should help with time–area-based management of intensively exploited migratory fish species, which requires rapid and accurate information.

Selected issues of optimising parameters on square riggers to maximise speed

AbstractDue to the exceptional complexity of the propulsion system (sails), square-riggers form a special group of sailing vessels. In modern pleasure and sport sailing, simple Bermuda (triangular) sailing rigging prevails, which is widely discussed in the literature, both in terms of theory and numerous experiments. The literature on the theory on square-riggers is, in turn, limited mainly to the description of good sailing practice developed over the centuries. Its important element was maximising vessel speed, but this discussion has not been documented by scientific research. This paper presents the significant parameters influencing the speed of a square-rigged sailing vessel and selects those which are the most important from the point of view of its maximisation. The paper also proposes methods and measurement systems which optimise selected parameters affecting the achievement of higher speeds. The paper describes the types of speeds of typical sailing vessels, provides a historical synthesis of sailing ships with respect to their speed, and presents a selection and description of the parameters affecting the speed of modern square-rigged vessels. The paper ends with a proposed method and measurement system for experimental research aiming at rigging optimisation in a square-rigged sailing vessel from the point of view of maximising its speed.

Rekonstrukcija forme trupa tradicionalnog hrvatskog ribarskog broda i predviđanje efektivne snage

Recently, an increasing attention is given to preservation and popularization of Croatian traditional boat building, which plays an important role in Croatian cultural and national heritage. Reconstruction and revitalization projects of individual historical vessels are key factors within preservation process, where the lack of technical documentation is one of the main issues. In this paper, a simple and efficient procedure for taking offsets of a traditional fishing vessel guc is presented to document and preserve the traditional Croatian vessel form. A 3D model of a guc is generated using the points on the hull surface obtained by the manual measurement and a fairing process. Numerical simulations of the resistance test for a fishing vessel are carried out for a wide range of speeds, and the curve of effective power as a function of vessel speed is provided.

Liner-Shipping Network Design with Emission Control Areas: A Real Case Study

In recent years, liner-shipping companies have faced a traditional trade-off between cost and emission (CO2 and SOX) reduction. This study considers this element to construct a liner-shipping network design model which includes a package-cargo transport plan, route allocation, and route design. The objective is to maximize profit by selecting the ports to be visited, the sequence of port visits, the cargo flows between ports, and the number/operating speeds of vessels. In addition, emission control areas (ECAs) exist in the liner network. With reference to the idea of the column generation algorithm, this study proposed a heuristic algorithm based on empirical data through a real case calculation and selected the optimal scheme, which is in-line with both economic and environmental benefits. The results show that the model and optimization method are feasible and provide an effective solution for the liner network design of shipping companies, while also considering environmental factors. In addition, the effects of the number of ECAs, inter-port origin-destination (OD) demand, freight rate, fuel price, and carbon prices on the design of transport networks are discussed to provide a reference for the operation of shipping companies and government decision-making.

Collisions of sailing vessels with cetaceans worldwide: First insights into a seemingly growing problem

Vessel-whale collisions are of growing concern worldwide, but information about collisions involving sailing vessels is especially scarce. This study represents the first global quantification of this kind. A total of 111 collisions and 57 near misses were identified, spanning from 1966 until 2010; 75% of cases was reported for the period from 2002–2010, suggesting an increasing trend. Reported collisions and near misses occurred on all oceans, often during ocean races and regattas, and were most frequent in the North Atlantic. Vessel type and speed as well as circumstances of the incident varied widely, but most often monohulls were involved, predominantly sailing at speeds between 5 and 10 knots. Most reports referred to ‘large whales’ as opposed to ‘small whales’ or ‘dolphins’. The species could be identified in 54 cases. Most recognised animals were humpback or sperm whales. Injuries to the whales varied strongly from ‘not visible’ to ‘dead after collision’, but mostly could not be determined. Sailing crew members were hurt in several cases, including collisions occurring at low speeds, and collisions often damaged vessels, including major impairment and seven cases of vessel loss. The findings presented here suggest that elevated vessel speed contributes to a higher risk of collisions. Conversely, the outcome of a collision (e.g. injury to whale or crew, damage to vessel) appears not to be a direct function of vessel speed. Several measures are discussed which potentially can contribute to mitigating the problem, including placing watchposts, an open dialogue with regatta organisers, changes in the design of regattas and ocean races and public outreach initiatives.

Effects of whale-watching activities on southern right whales in Encounter Bay, South Australia

Southern right whales (Eubalaena australis) are listed as Endangered under the Australian EPBC Act 1999. They migrate to shallow, coastal waters during the winter to mate, calve and nurse their young. During this time, they are easily accessible to the boat-based whale-watching industry. The aim of the study was to determine if whale-watching at 300 m distance affects the behaviour of southern right whales. To achieve this, behavioural focal follows on mother-calf pairs were conducted using unmanned aerial vehicles (UAVs) in the presence and absence of a commercial whale-watching vessel. There was no significant effect of phase (control, before, during, after) on the whales’ respiration rate, swim speed, nursing rate and duration, maternal rate of active behaviours, tactile contact or calf pectoral fin contact. There was a significant reduction in resting between control and after phases, for both mothers (from 62% to 30%) and calves (from 16% to 1%). At 300 m distance and slow speed, vessel noise was measured to be slightly above ambient noise at the lower TOL0.25 kHz band, however, vessel noise was masked by ambient noise within the higher frequency TOL2–10 kHz bands. A factor which may have contributed to a decline in resting after whale-watch approaches, was an increase in vessel speed upon departure, which consequently increased vessel noise. Based on this, we recommend that vessels maintain a slow speed (e.g., ≤10 knots) within 1 km distance from the whales whilst conducting whale-watch activities.

Self-labelling of tugboat operation using unsupervised machine learning and intensity indicator

The actual operational data, such as a time sequence of fuel consumption and speed, is usually unlabeled or not associated with a specific activity like tugging or cruising. The operation type is critical for further analysis, as tugging and cruising operations require different fuel and navigation profiles. This paper aims to develop a self-labelling framework for tugboat operation by using unsupervised machine learning and a proposed intensity indicator. The framework considers two sets of data: the positional data and the fuel consumption rate data. The fuel consumption data is obtained from mass flowmeters installed on tugboats, while the positional data are navigational data purchased from marine data aggregators. The developed self-labelling enables ship operators in identifying operations and locations that require heavy fuel consumption andcan be used for further big data analytics and machine learning for fuel consumption prediction when vessel speeds are known.

Modelling whale-vessel encounters: the role of speed in mitigating collisions with humpback whales (Megaptera novaeangliae)

Increasing whale populations and vessel traffic worldwide has led to an increase in reported whale-vessel collisions. This paper reports on factors that affect the rate of whale-vessel collisions in the four-island region of Maui, Hawai’i. More specifically, it aims at quantifying the probability of a whale-vessel collision with varying vessel speeds using encounter distances as a proxy. A change point model was used to identify a speed threshold of 12.5kts (6.4m/s), which showed a significant change in the relationship between speed and mean sighting distance. A 3.4-fold decrease in close encounters with humpback whales was observed when vessels travelled at speeds of 12.5kts (6.4m/s) or less. Furthermore, results indicate that lone adult whales and calves are the most likely to be involved in a collision. A speed limit of 12.5kts (6.4m/s) is warranted in areas and/or during seasons where a high density of whales occurs. This limit aligns with a reduction in lethal vessel strikes with speed from previous studies which found a significant increase in the likelihood of mortality when vessel speed exceeds 12kts.

Policy enabling North Atlantic right whale reproductive health could save the species

AbstractNorth Atlantic right whales (Eubalaena glacialis) risk extinction unless conservation measures not only reduce mortality but also enhance reproduction. Vessel collisions injure and kill by spinning propeller cuts or being hit with a blunt structure resulting in bone and soft tissue damage. Entanglement trauma includes sublethal injuries that can reduce their ability to reproduce, while lethal events include drowning, deep constricting wounds, and emaciation leading to death over months or years. Current regulations attempt to reduce mortality from vessel strikes and fishing gear entanglement off the eastern shores of the United States and Canada. However, sub-lethal stressors, especially entanglement, have exacerbated impacts from climate-driven food supply changes, resulting in a serious reduction in growth of individuals and calving rates. If consumers demand that their ship-borne goods and bottom-caught seafood be procured without serious welfare and health concerns for the whales, recovery is possible. We need the will to widely employ the tools of vessel speed restrictions and acoustic retrieval of bottom traps and nets without a persistent vertical line in the water column to reduce sub-lethal as well as lethal trauma. Thus, consumers should pressure legislators, endangered species managers, and suppliers for far broader protections than currently exist.

Wind-Assisted Ship Propulsion of a Series 60 Ship Using a Static Kite Sail

Following the International Maritime Organization’s goal to reduce greenhouse gas emissions, the interest in the application of wind-assisted ship propulsion (WASP) in maritime transportation is on the rise. Although a variety of WASP systems exist, the application in maritime shipping is still limited, especially in the case of kite sails. This paper presents a numerical model to carry out a theoretical assessment of the influence of the kite planform area and wind speed on the aerodynamic performance of a kite sail providing propulsive assistance to a 75 m long ship having a Series 60 hull. A static kite sail is assumed, on which a tail wind generates a thrust force to pull the vessel via a tether. While the mass of the kite is neglected, that of the tether is accounted for. A model is implemented for the tensioned tether having a catenary profile. The results generally show a positive correlation between the aerodynamic forces and the kite parameters. As expected, the output parameter values corresponding to the optimal angle of attack for a range of vessel speeds are also found to increase with an increasing relative wind speed. It is concluded that a static 320 m2 kite sail would be sufficient to meet the entire propulsion requirements of the vessel under consideration under appropriate wind conditions.

Integrated behaviour decision-making and trajectory tracking for dynamic collision avoidance of an ASV using receding horizon optimisation

This paper develops a receding horizon optimisation scheme for integrated behaviour decision-making and trajectory tracking to ensure the dynamic collision avoidance of an autonomous surface vessel (ASV). We apply Q-learning to make behaviour decisions because manoeuvring habit requirements and COLREGS must be satisfied in dynamic collision avoidance scenarios. The heading course and vessel speed are considered to transmit the outcome of behaviour decision-making to a trajectory tracking model predictive control (MPC) controller. Next, a trajectory tracking nonlinear controller for the ASV is developed within the MPC framework, in which a set of nonlinear constraints is designed for collision avoidance. Specifically, depending on the heading course and vessel speed, the collision avoidance constraints can be switched to allow the controller to execute the behaviour decision. Simulation results verify the effectiveness of the proposed receding horizon optimisation scheme.

Trajectory Tracking Control for Vector Propulsion Unmanned Surface Vehicle With Incomplete Underactuated Inputs

Considering different propulsion systems of unman- ned surface vehicles (USVs), it is necessary to design corresponding vessel motion controllers according to propulsion characteristics. This article devotes to solve the problem of trajectory tracking control for vector propulsion USV. By analyzing actuator distribution of vector propulsion, the vessel can be regarded as an incomplete underactuated system, and the control inputs adopt thruster speed and propulsion angle which are closer to reality. On this basis, the guidance trajectory and adaptive sliding mode controller based on virtual control point theory are proposed to realize trajectory tracking control of vector propulsion USV with system uncertainty and external disturbance. The designed guidance trajectory can guide the vessel to return to the desired trajectory when position error is large, and the system stability is illustrated by stability proof. Then in the design process of the controller, to mitigate chattering for sliding mode, a continuously derivable approximate saturation function is used instead of the signum function. Next, by zero-dynamics stability analysis, the position of the dynamic virtual control point is obtained with the relationship between the virtual control point and vessel speed. Finally, numerical simulations are carried out with two kinds of trajectory tracking scenarios to verify the correctness and feasibility of the proposed control strategy.

Anthropogenic activity, hydrological regime, and light level jointly influence temporal patterns in biosonar activity of the Yangtze finless porpoise at the junction of the Yangtze River and Poyang Lake, China.

Under increasing anthropogenic pressure, species with a previously contiguous distribution across their ranges have been reduced to small fragmented populations. The critically endangered Yangtze finless porpoise ( Neophocaena asiaeorientalis asiaeorientalis), once commonly observed in the Yangtze River-Poyang Lake junction, is now rarely seen in the river-lake corridor. In this study, static passive acoustic monitoring techniques were used to detect the biosonar activities of the Yangtze finless porpoise in this unique corridor. Generalized linear models were used to examine the correlation between these activities and anthropogenic impacts from the COVID-19 pandemic lockdown and boat navigation, as well as environmental variables, including hydrological conditions and light levels. Over approximately three consecutive years of monitoring (2020-2022), porpoise biosonar was detected during 93% of logged days, indicating the key role of the corridor for finless porpoise conservation. In addition, porpoise clicks were recorded in 3.80% of minutes, while feeding correlated buzzes were detected in 1.23% of minutes, suggesting the potential existence of localized, small-scale migration. Furthermore, both anthropogenic and environmental variables were significantly correlated with the diel, lunar, monthly, seasonal, and annual variations in porpoise biosonar activities. During the pandemic lockdown period, porpoise sonar detection showed a significant increase. Furthermore, a significant negative correlation was identified between the detection of porpoise click trains and buzzes and boat traffic intensity. In addition to water level and flux, daylight and moonlight exhibited significant correlations with porpoise biosonar activities, with markedly higher detections at night and quarter moon periods. Ensuring the spatiotemporal reduction of anthropogenic activities, implementing vessel speed restrictions (e.g., during porpoise migration and feeding), and maintaining local natural hydrological regimes are critical factors for sustaining porpoise population viability.

A ship performance and genetic algorithm based decision support system for vessel speed optimization of ocean route

A ship performance and genetic algorithm based decision support system for vessel speed optimization of ocean route

A ship performance and genetic algorithm-based decision support system for vessel speed optimisation of ocean route

A ship performance and genetic algorithm-based decision support system for vessel speed optimisation of ocean route

Green maritime: An improved quantum genetic algorithm-based ship speed optimization method considering various emission reduction regulations and strategies

Different organizations and countries have proposed a variety of policies and strategies to reduce emissions from the shipping industry. These include the Emission Control Area (ECA) policy, carbon tax policy, Vessel Speed Reduction Incentive Program (VSRIP), and Virtual Arrival (VA) strategy. These policies and strategies create additional costs for ships, forcing the ships to change their speeds or routes. This highlights the need to study approaches that optimize the sailing speeds of ships, by coordinating the implementation of the multiple governing policies and strategies. This paper develops a cost model that considers different emission reduction policies and strategies; this is followed by an analysis of their effect on emissions reduction. In addition, the paper proposes an improved quantum genetic algorithm based on a “fork gene” and elite strategy, which is specifically designed for specific shipping-related policies and strategy. The model is applied to a shipping route on the United States (US) West Coast, with three key findings. First, the improved algorithm significantly reduces the total cost, compared with the original alternative, in the context of emission reduction policies and strategies. Second, a single policy can produce positive results in reducing emissions, and the coordinated implementation of three separate policies (ECA, carbon tax, and VSRIP) may not lead to better results than a single policy. Finally, adding the VA strategy above and beyond the three other emission reduction policies may create more benefits in reducing emissions and operating costs.