Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The short-term weather variability affects expenditures for a ferry on the Gdynia-Karlskrona route has been studied in this study. The combination of an operational framework with a subsystem-level cost model covering navigation, propulsion/steering, leading/unloading, stability control, and mooring/anchoring have been conducted to support this investigation. This study is interesting however there are some drawbacks that the authors should address them to improve this study.

1. In the abstract, the authors must state clearly the operation costs of a ferry from this study through battery energy management based on impacting on weather variability.
2. In the introduction, the authors stated the statements to address the gap of research: ‘This study addresses this gap by developing a novel modelling framework that treats weather variability not an exogenous disturbance, but as a central, endogenous parameter in ferry operational cost dynamics. Drawing from concepts in multi-state reliability theory and climate-resilient asset management, the proposed approach integrates stochastic system modelling, …’ The authors have not stated the objects of study from these statements. Additionally, the importance of the novelty points must be indicated clearly especially the proposed methodologies.
3. In table 1, operating states of the maritime ferry, the authors have divided into 18 states with its description. However, the characteristics of each operation state and time, respectively should be provided clearly to help the readers to understand clearly the surveyed routes.
4. In tables 3, 4, the authors must explain the category with each fist, second, third order at each weather state.
5. The wind direction with each angle should be presented graphically to show clearly the weather condition impacting on ferry.
6. How to get the wind speed (m/s) and wave height (m) for these tables?
7. The calculation of cost adjustment coefficients by category of extreme weather hazards should be provided under Appendix format to explain Table 7.
8. The significance of this cost analysis should be concentrated significantly to reflect the impacts on the operational process of ferries.
9. The cutting-edge methodologies should be analysed intensively to evaluate clearly the proposed method.

 

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The article "Impact of Weather Variability on the Operating Costs of a Maritime Ferry," prepared by Beata Magryta-Mut and Mateusz Torbicki, is submitted for review as a completed research paper. This research was funded by the statutory activities of Gdynia Maritime University, grant numbers WN/PI/2025/05 and WN/PZ/06/2025.

This article, submitted for review, should be considered as material that addresses the most important aspects of transport operation – the impact of operating conditions on the reduced costs of performing established work.

The authors note the specific features of sea ferries, which operate in unstable hydrometeorological conditions. This complicates operational cost planning. This study analyzes how short-term fluctuations in weather conditions affect the operating costs of a ferry operating on the Gdynia–Karlskrona route. The authors attempted to combine an operational model based on 18 discrete ferry movement states with a cost model at the control and operational subsystem level. This applied to issues covering navigation, propulsion and steering systems, loading and unloading operations, stability monitoring, and mooring/anchoring. The authors linked direct and indirect costs to subsystem activity and the duration of each of these states. The authors also attempted to incorporate weather conditions into the analysis through hazard categories, which scale hourly costs. An assessment was made using high-hazard scenario modeling. The authors obtained a specific cost structure that identified the primary share of monthly expenses and identified an insignificant contribution from operating costs. The authors determined the impact of weather risks across various scenarios. The authors identified the potential for improving resilience to cost increases. The influence of these factors was assessed using a probabilistic model. The authors believe the study may be useful to operators and policymakers. It provides them with a methodology for climate-resilient planning and investment in semi-enclosed shipping lanes.

The authors' work and the resulting article as a whole are quite interesting and quite important for specialists and readers. The article will be of interest to navigation specialists, marine engineers, fuel specialists, crewing company managers, and other interested parties. However, alongside its positive aspects, there are also some shortcomings, the elimination of which will help the authors improve the article's text and its comprehension by specialists and readers. To better facilitate the understanding of this article by specialists and readers, it is advisable to address several identified shortcomings and inaccuracies:

1. The article title, abstract, keywords, and conclusions require more thorough correlation. Many of the keywords are irrelevant to the article title and conclusions. Furthermore, without a complete correlation between the keywords, conclusions, and the text of the article itself, it is difficult to speak of the validity of the presented facts. Therefore, I recommend addressing this shortcoming. This will undoubtedly lead to a better perception and understanding of the article by specialists and readers.
2. The article describes an operational model for vessel movement along a route. However, it is unclear from the text whether this is an original development or a presented functionality implemented by the shipping company. This determines the degree of reliability assessment of the operation stages and their probability. It is also unclear which limitations and fixed points were established experimentally and with what probability. It would be advisable to clarify these provisions.
3. When establishing a cost model, it would be advisable to separate them and justify them at the level of subsystems covering navigation, propulsion and steering systems, loading and unloading operations, stability control, and mooring/anchoring. It is unclear how this data was established and how it was separated from the overall balance of work on the vessel. How exactly the monetary equivalents of costs were determined.
4. It is unclear how the hazard categories that scale hourly costs were determined and how this is directly related to natural and climatic conditions. Furthermore, it is unclear how all components of natural and climatic factors in vessel operation were assessed and with what probability.
5. The authors' abstract cites estimates obtained from experts, but does not specify the methods or qualifications of the experts. This is not convincingly presented in the text. They describe monthly durations of conditions used for basic calculations and modeling of high-risk scenarios. However, the text of the article does not specifically highlight the statistics of monthly conditions, does not show models of high-risk scenarios, and does not substantiate potential, increased, and high-risk events for the vessel.
6. General мy wish is for a more thorough justification of changes in natural and climatic factors and the monetary equivalent of vessel operation.
7. The abstract indicates that adaptive route and speed management, as well as targeted maintenance, provide the greatest potential for increasing resilience to cost increases. However, these indicators are not specifically presented in the text of the article in relation to each criterion separately and vessel operating costs. Furthermore, it is not specified how forecasts are formed based on these criteria or on what vessel operating conditions they are based.

The article is quite interesting and important from the perspective of practical vessel operation. It can be submitted to the journal after the aforementioned comments are addressed.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

1. In abstract, could authors give more detail to clarify the method used and critical findings with numerical values if possible? Following a more detailed set of key findings, along with how these findings contribute to the existent body of empirical relevant research, revising the existent implications by highlighting the contribution is suggested. 

2. Introduction: 

A) In introduction, the level of discussion is satisfactory however thereare too many directions suggested in this section, and this section should be made more concise. Further, for numerical statements, could authors revise the sentencing and referencing? Let me give an example. At line 49: "... failure to incorporate real-time or forecast-based environmental data into operational planning leads to systematic underestimation of maintenance frequency by 30–50% and lifecycle costs by 18–25% in high-variability regions [13]."
Could it be made as "As shown by Surname et al. (Year) after examining ... data with ... method, systemic underestimation is documented. Accordingly,the level of underestimation varies in the range of 30 to 50% [13]. 

Also, instead of relying to a single source, could authors provide a discussion with comparative statements: In contrast, in the study of ..., the underestimation is confirmed however with a relatively lower ratio ranging between 20-30%. 

B) Focusing on cost concepts is critically adressed. However, from an economic perspective and also shown by a body of research, in addition to cost on the supply side, demand side is also important. For instance, in BDI related literature, the variability of BDI is shown to be under the influence of time inconsistency of ship building which takes a long time, and during economic downturns, as demand decreases for shipments, however, during expansionary growth periods, the sector cannot catchup with increased demand pushing shipment costs upward. So, my suggestion is also to introduce economic concepts and freight costs relationship. 

C) For introduction, it should again be repeated that methodological clarity should be presented here, since it is unclear to the reader. 

D) Lastly, at the last section of section 1, stating the sectioning briefly (Method is presented in Section 2...type of explanation as commonly applied) is helpful for the reader. 

3. Method and results sections:
 
A) Method choice should be justified. 

B) Develop data justification, provide sources more clearly, detail dataset and why it is considered as a rich dataset, sample size and descriptive statistics should be added. To this purposes, extending existing table and forming a more detailed explanation with units (cost per hour in dollars?), source, measurement, any transformations made, followed by basic statistics for moments and min max, and if possible statistics for distributional characteristics. 

C) Authors stated that costs were determined on judgement, which would yield to questioning, and to overcome this weakness, how many experts were used, method used, statistical significance, measurement validity analysis, Cronbach alpha explanations are needed.

D) In results, could authors incorporate uncertainty with standard errors confidence intervals or t tests? 

E) Discussion section should be developed with discussion with existent empirical research with comparative analysis of findings. 

F) The method itself benefits from uncertainty and probabilistic concepts defined by exogenous markov chains determining regime changes. However, the overall statements are too strict especially the tables. Certain Markov regime probabilities are very high, indicating persistence, and very high durations for different regions examined. While the others are very low in terms of probability indicating low persistence and low durations and chance of switching to the high persistent regime. Could authors discuss them in more detail with implications, and do these results represent a general tendency, aren't these results open to suprise shifts to different regimes, sudden changes to different weather dinamics unexpectedly? My concern is, the probabilistic nature should be more highlighted. Extending the discussion below tables for Markov results, adding statistical significance and uncertainty would further help, for example *, **, *** for significance levels and/or adding confidence intervals and updating interpretations accordingly afterward is suggested.   

G) As of it is, limitations section is too long because future directions are also presented in it. I suggest several steps, moving limitations to the end of conclusıon first; then, seperating the future directions section and making it another subheading of conclusion.

4. Conclusion can ve made sharper by highlighting contribution, more emphasis on method and critical findings, along with comparison to existent research.  Also, in conclusion, conclusion also has limitations section and future directions sections embedded, and after critique (G) above, a single and more direct, and focused limitations and future directions sections should be given. However, extending the conclusion itself and making it more specific instead of general statements is also necessary, a deductive form should be followed, also, note that it is too short once limitations and future directions are substracted. So, the sections before implications should be extended in conclusions.   
   
5. Extending literature and references with recent studies.   

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The revised paper has been improved for accepting to publish on Water. 

Reviewer 3 Report

Comments and Suggestions for Authors

Authors provided a throughout revised manuscript that addresses issues directed in the previous round.