Impact of Port Shallowness (Clearance under the Ship’s Keel) on Shipping Safety, Energy Consumption and Sustainability of Green Ports

Round 1

Reviewer 1 Report

This article proposes a method for calculating the optimal ship’s speed propagated in port navigation channels and port waters areas based on minimum fuel consumption. Through the analysis of existing cases and literature, author selected the variables and parameters that need to be considered in this study and established a mathematical theoretical model. The method proposed in this article was verified through simulation experiments conducted on the simulator. Here are some of my suggestions for this article：

1.      The format of the formulas in Section 3 needs to be adjusted；

2.      Line 107 has redundant symbol；

3.      Authors need to emphasize the novelty of the method proposed in this article.

Minor editing of English language required.

Author Response

Dear Reviewer,

Thanks a lot for the review and we send our responds to Your comments.

Best regards

Authors

Author Response File: Author Response.docx

Reviewer 2 Report

The authors worked on modeling and improving the current conditions by addressing a situation experienced in ports in maritime transportation, which has become increasingly important today. A few minor corrections that will improve the quality of the article are noted below. 

Reference number 46 given in the list of references has not received any citation in the text. If this source is not used in the text, it is recommended to remove it from the references list.

The order of citations to the references in the text should be reviewed. While source number 65 was first cited in line 503, it was seen that sources 66-70 were cited before. In general, it is recommended to review the reference list and the citation order of the references.

While referring to the figures, it has been seen that sometimes "Figure" and sometimes "figure" are used. Here, it is recommended to correct the figure spellings to Figure.

The figure caption expression used for Figures 9 and 10 was found to be quite long. Figure and table titles are expected to be short definitions that express the figure and the table. Explanations about these should be given in the text.

It is sufficient to give the explanations given for abbreviations once in the text. Although the abbreviation expression is given for Vessel traffic system, the explanation is given again many times. Unnecessary repetitions of all abbreviations and explanations used in the text should be reviewed and corrected. T/H abbreviations and explanations should be arranged in a similar manner. 

In the text, it is stated that "the minimum ship speed depends on the external impact forces (wind, current, waves)". In this study, the safe wind speed range is not specified. What is the range of wind speed in which the ship can travel safely?

In the discussion section, it is recommended that the results of the study be supported by the literature. 

Author Response

Dear Reviewer,

Thanks a lot for Your review and we send our response to Your comments.

Best regards

Authors

Author Response File: Author Response.docx

Reviewer 3 Report

This is an interesting research paper in an area of relative significance in these times of environmental and energy concern. The article is well structured and the referencing appropriate and accurate. The scientific method is well explained and is very suitable for the problem in hand. In broad terms it is a valuable contribution to the discipline because it attempts to conflate economic and social issues with those of a practical and commercial industry along with scientific methodologies and then this is all placed in an interesting spatial location which has been uncommonly used. The discussion and conclusions are suitable and relate well to the problem in hand. 

The main reason for the average or lower ratings stem from the quality of English and in particular the structure of the language which at times is very awkward. This does not mean that the meaning of the paper is unclear but that reading it becomes slow and difficult. These problems feature in all sections - sundry, key words, main body - and needs to be addressed before publication is suitable. One classic example is in the summary where the second sentence (lines 15-17, has six mentions of "ship". In the keywords the word ~"ships" should either be "ship" or `"ship's" ....

Please see above

The main reason for the average or lower ratings stem from the quality of English and in particular the structure of the language which at times is very awkward. This does not mean that the meaning of the paper is unclear but that reading it becomes slow and difficult. These problems feature in all sections - sundry, key words, main body - and needs to be addressed before publication is suitable. One classic example is in the summary where the second sentence (lines 15-17, has six mentions of "ship". In the keywords the word ~"ships" should either be "ship" or `"ship's" ....

Author Response

Dear Reviewer,

Thanks a lot for Your review and we send our response to Your comments.

Best regards

Authors 

Author Response File: Author Response.pdf

Reviewer 4 Report

The paper assesses the optimal speed of ships in port aiming to contribute to the reduction of fuel consumption and ship emissions in ports. The authors aimed to determine the optimal speed of ships in ports, by presenting a methodology of optimal ship speed calculation.  

The introduction section is too general for the topic of the paper being focused on the safety and maneuverability of ships in ports as well as probability of ship collisions. It should include in-depth description (from appropriate literature) of the state of the art concerning methods and algorithms for assessing the optimal speed of ships. Moreover, there should be included relevant data from literature or from statistics concerning the contribution of ship transit in port to share of GHG emissions.

Aren’t standards and specific requirements for ships behavior in ports, including the speed of movement?  

The authors specified that” The generation of emissions when a ship navigates port navigation channels and port water areas depends on the amount of fuel consumed, the power used by the engine(s) and the engine(s) working time” – In this context aren’t many factors that lead to subjectivity of speed choice upon the weather characteristics, ports configuration, channel dimensions, ports depth, congestion in the port?

How is the suitable for all situation? Can the mathematical model be applied for all the situations? The model can be extrapolated?

In terms of fuel consumption and associated emissions…The study and the conclusions included all the types of fuels (LNG – Liquid natural gas. Heavy Fuel Oil. Very-low Sulphur Fuel. Ultra-low Sulphur Fuel. Biofuels) that can be used by ships? What’s the share of emissions reduction for each case?

The conclusions of the authors are too general, not connected with data from the performed research and must be more specific to the achievements in terms of optimal speed resulted from the applied model, fuel consumption reduction, emissions reduction, detailed impact on sustainable goals, contribution to greener ports, effective contribution to sustainability.

Which are the improvements in model applied, considering the research performed in: 7.Vytautas Paulauskas, Ludmiła Filina-Dawidowicz and Donatas Paulauskas. The Method to Decrease Emissions from 737 Ships in Port Areas. Sustainability, 2020, 12, 4374; doi:10.3390/su12114374

The equations formatting must comply with the template of the journal.

The authors should revise the manuscript and reformulate some phrases that are unclear. For example:

”Moreover, research results may have managerial implications. Seaports, as well as  shipping companies, may change their procedures and introduce strict conditions of skill  verification during employee hiring and professional work, in pursuit of optimizing the ships speed in port navigational channels and port waters and as well emissions at sea ports.”

”At the same time, the tested vessels do not need to use high engine power for braking when entering the turning basin, which also reduces energy (fuel) consumption and generates minimal emissions during this operation.”

”The results of theoretical and experimental studies obtained in this way allow them to be applied in determining the possible optimal speed of ships in port navigation channels and port water areas.”

and some others...

Author Response

Dear Reviewer,

Thanks a lot for Your review and we send our response to Your comments.

Best regards

Authors

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Ready to publish

Reviewer 4 Report

The authors improved the initial manuscript concerning the issues suggested in the report review. 

The answers provided are a good explanation for the issues mentioned in the paper by the authors.

No