Simulation-Based Operational Evaluation of a Single-Berth Multipurpose Seaport with Wharf Space Restriction

Round 1

Reviewer 1 Report

Dear Authors,

Here are my best suggestions for the improvement of your manuscript. Hope to be helpful for you:

Some conceptual suggestions:

• Clarify in the Section 2-Literature review, the most relevant simulation methods which are being applied to terminals nowadays: discrete-event simulation, micro-simulation (not mentioned in the manuscript: you can read about it in Hervás-Peralta, M.; Roži´c, T.; Poveda-Reyes, S.; Santarremigia, F.E.; Pastor-Ferrando, J.-P.; Molero, G.D. Modelling the performance of port terminals using microsimulation. Eur. Transp. Trasp. Eur. 2020, 76, 1–11.) etc... and describe positive and negative points per each one, then justify the selection of "discrete-event simulation".
• It is needed to correlate the 3 KPIs in this study: The number of lifts/hour extracted from the capacity simulation is 6 lifts/hour (47023/365=129 lifts/day; 129/21 = 6 lifts/hour) considering 21 operational hours in the port. This figure is contradictory with the productivity calculations where we can arrive with 3 trailers and 2 yard reach stakers to 14,5 lifts/hour. This correlation between the 3 KPIs (including "utilization")  should be done in the Figure 11 and in the Table 3 and Figure 15. 
• In this last case (Table 3 and Figure 15), the % of utilization of the vessel crane should be considered to analyze if this productivity is compatible with the utilization of the vessel cranes. Or perhaphs, limitations in the vessel crane utility will reduce the productivity of the handling equipment.
• A table (similar as table 1 in Appendix A) with 3 lines: "Real situation", "Improved situation with the same handling methods", "Ideal situation with new handling methods" where the 3 KPIs: Utilization, Productivity and Capacity are detailed per each situation could provide a great value. This table could be placed in the Section 6.- Conclusion
• Lines 339 to 341 should be reworded, as they seem more appropriate for a consultancy report than for a scientific publication: What the Indonesian's port operators decide is not the main issue, the most relevant point is that simulation methods have been used in the decition making process for port operators.  How simulation models can be used for decition making should be enhanced in this section about conclusions.
• A more detailed description of the scientific or technical method underlying the software "Plant simulation" should be also introduced in the Section 4.2. The main issue is not what software has been used, but how this software is working and what it is doing. This will help the readers to apply similar methodologies to their own problems. Consequently, the next information should be added to the text: information about simulation models, why the Authors decide to choose Discrete-event simulation as the best one to be applied to this problem, how events should be parametrized (values assigned to each event) and how results should be handled to make decitions.

Some suggestions related to the format:

• Include in the title the word: "single-berth". A recommendation should be the next title: "Simulation-based operational evaluation of a single-berth multipurpose seaport with wharf space restriction"
• Figure 3 should be redesigned in a linear and more clear way.
• The word "loose cargo" should be replaced by "break bulk cargo" in order to be consistent with the previous text.
• In the Subsection 4.2.-Simulation model, the 4 types of process depicted in figures 5, 6, 7 and 8 should be correlated with the flowchart depicted in figure 4 in order to gain clarity.  
• In the Subsection 4.2.-Simulation model, it is required to describe the version of the software "plant simulation" and provide some detailes about it (a reference about how to download it and if it is free or not)
• The yard operation process described in lines 199 to 203 is only referring to containers and not to "break bulk cargo".
• Clarify what "ergo" is in line 209.
• Clarify what are the 7 methods objects mentioned in line 211.
• Correct lines 222 and 223 with the appropriate hours in order to sum 24 hours. 
• Define what KPIs: "Productivity" and "Capacity" are measuring, in the same way that was done for the KPI: "Utilization". 
• Clarify how many "quay reach stakers" are being considered in the capacity calculation in the Section 5.2.
• In this section 5.2, define what is understood by "waiting time" and "interval hours".
• In this section 5.2, it would be valuable to mention again, after the line 269, the current real capacity detailed in the page 4 in section 3, to compare it with the simulated one.
• In this section 5.2: Clarify how the amount of 40260 TEUs and 31,223 Tons of Loose cargo is calculated.
• In this section 5.2: Justify why the break bulk cargo weight is considered 4.02 Tons.
• In the line 265: Explain to who, when and how (method) this consultation was done.
• Replace Figure 9 per Figure 11 in line 277
• Place the figure 12 after explanation of its meaning: Lines 283 to 293.
• Correct title in the Table 2 
• Clarify if 1 vessel crane or 2 vessel cranes are considered in the Figure 12 about utilization. 

Thanks very much for considering all these suggestions.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

In my opinion, the material can be used as a starting point for further developments, is at an early stage and requires a lot of work to be published later in the journal.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Dear Authors,

Thanks very much for addressing all my suggestions. It is very appreciated. 

However, there are still 3 points to be improved:

• The number of each reference is missing in the Section 2.-Literature review.
• The parragraph that you indicate in your point 3 of the cover letter is missing in the submitted version of the paper: “The utilization rate of the vessel cranes when dealing with different kinds of cargo is taken into consideration. The productivity is compatible with the utilization of vessel cranes when dealing with containers. But for break bulk cargo, the productivity is limited by the number of vessel cranes. In reality, the amount of break bulk cargo is less than the half of containers, so the suggested coworking of 2 vessel crane is acceptable. For containers, When the number of straddle carriers is increased, the productivity keeps rising as long as the system is not restricted by other facilities. This trend is shown clearly in Figure 14.” 
• The Table 4 and the text that you mention in the point 4 of your cover letter is missing in the submitted paper: “To summary these 3 handling methods, we first label them as A, B and C.
  A, real situation. The data is originated from the annual report of the cargo jetty in 2019 and productivity and utilization are unknown.
  B, improved situation with the same handling method. The data is originated from the simulation results, 4 trailers, 2 YRSs, 1 QRSs and a vessel crane are involved.
  C, ideal situation with new handling method. The data is originated from the simulation results, 6 straddle carriers, 5 YRSs and 2 vessel cranes are involved. Note that the utilization of vessel cranes includes two values calculated when dealing with containers and break bulk cargo, respectively.”

The rest of my comments were appropriately addressed. Thanks very much.

Author Response

We thank the reviewer very much for your effort to review our manuscript and for your detailed comments and suggestions. In this revision we have incorporated all of them. Our point-by-point response is given below.

Point 1: The number of each reference is missing in the Section 2.-Literature review.

Response 1: We are sorry for the mistakes. We have fixed this error in the latest version

Point 2: The parragraph that you indicate in your point 3 of the cover letter is missing in the submitted version of the paper: “The utilization rate of the vessel cranes when dealing with different kinds of cargo is taken into consideration. The productivity is compatible with the utilization of vessel cranes when dealing with containers. But for break bulk cargo, the productivity is limited by the number of vessel cranes. In reality, the amount of break bulk cargo is less than the half of containers, so the suggested coworking of 2 vessel crane is acceptable. For containers, When the number of straddle carriers is increased, the productivity keeps rising as long as the system is not restricted by other facilities. This trend is shown clearly in Figure 14.” 

Response 2: Sorry for the error, we have added this paragraph in the latest version.

Point 2: The Table 4 and the text that you mention in the point 4 of your cover letter is missing in the submitted paper: “To summary these 3 handling methods, we first label them as A, B and C.
A, real situation. The data is originated from the annual report of the cargo jetty in 2019 and productivity and utilization are unknown.
B, improved situation with the same handling method. The data is originated from the simulation results, 4 trailers, 2 YRSs, 1 QRSs and a vessel crane are involved.
C, ideal situation with new handling method. The data is originated from the simulation results, 6 straddle carriers, 5 YRSs and 2 vessel cranes are involved. Note that the utilization of vessel cranes includes two values calculated when dealing with containers and break bulk cargo, respectively.”

Response 3: Sorry for the error, we have added this paragraph in the latest version.

Reviewer 2 Report

None

Author Response

We thank the reviewer very much for your effort to review our manuscript.