Exploration of Alaska’s World War II Submerged Heritage: The Kotahira Maru and SS Dellwood Wreck Sites off Attu Island

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This is an excellent synthesis of historical and archaeological data, demonstrates best practices in regard to the selection and deployment of the remote sensing equipment, and offers a sensitive approach to a difficult heritage of indigenous displacement, war and loss of life, especially in the case of Kotohira Maru.  The conditions for field work are daunting, and the project's successful results have provided additional and valuable information for the Aleutians campaign, understanding of the context of both vessels for management and interpretation, and your sources are well-selected and appropriate.  The presentation of the data from the field work is exceptional.  Having dived on and studied a few WWI Emergency Fleet vessels, you nailed Dellwood's context and remains perfectly.  

Author Response

Comments 1: This is an excellent synthesis of historical and archaeological data, demonstrates best practices in regard to the selection and deployment of the remote sensing equipment, and offers a sensitive approach to a difficult heritage of indigenous displacement, war and loss of life, especially in the case of Kotohira Maru.  The conditions for field work are daunting, and the project's successful results have provided additional and valuable information for the Aleutians campaign, understanding of the context of both vessels for management and interpretation, and your sources are well-selected and appropriate.  The presentation of the data from the field work is exceptional.  Having dived on and studied a few WWI Emergency Fleet vessels, you nailed Dellwood's context and remains perfectly.

Response 1: Thank you very much for taking the time to review this manuscript.

 

Reviewer 2 Report

Comments and Suggestions for Authors

Comments and Recommendations:

Exploration of Alaska’s World War II Submerged Heritage: The Kotahira Maru and SS Dellwood Wreck Sites Off Attu Island

Dominic Bush and Jason T. Raupp, and Alexander Unrein

 

Overall Assessment

The article features thematic originality and a sound theoretical framework that links the local history of Attu Island, the Second World War theatre of operations in the North Pacific, and the underwater cultural heritage associated with this conflict. The work presents a clear objective and, in my view, is well structured and developed in order to achieve that objective.

The investigation of the historical context at different scales is very comprehensive, and the work proposes a fruitful dialogue between historical information and the archaeological case studies, namely the wrecks of the Kotohira Maru and the SS Dellwood.

The methodological section is thorough with regard to the technical aspects of the equipment used in the survey and recording, as well as the management of the data obtained. The results are well structured and present a clear and concrete description of the wrecks. The discussion is consistent with the evidence presented and with the stated objective.

1. Introduction

The introduction provides a good contextualisation of the article, sets out a clear objective, and provides a theoretical foundation for the relevance of the research, as well as its importance for understanding and recovering knowledge of the cultural heritage associated with the North Pacific theatre of operations, particularly that linked to Attu Island.

2. World War II History of Attu

This section is very well structured and allows the reader to understand the context of the Second World War at a regional scale (North Pacific).

General map of the region: other islands of the Aleutian archipelago are mentioned but are not referenced on the map presented in the article. It is recommended, if feasible, to include a map of the region indicating the places mentioned that are closest to Attu, especially the lesser‑known ones named in the article. This does not affect the central understanding of the text but would allow the reader to follow the reading more easily.

Nor has the location of the wrecks been indicated on a map; however, it is understood that the location may be considered sensitive information, so I leave this decision to the authors and editors.

3. Vessel Narratives (Kotohira Maru and SS Dellwood)

Both the technical description and the history of the vessels, as well as the circumstances that led to their sinking, are very well presented. The plans of the two ships constitute very interesting documentation and a valuable contribution. However, the limitations of the format make them difficult to appreciate. If possible – via a hyperlink – it would be advisable to present the plans at a larger size and resolution.

4. Materials and Methods

This section focuses on the equipment, its use and the management of the information obtained.

Suggestion: Given that the article represents the first remote sensing study of the submerged heritage of Attu Island, carried out over five days, and that two shipwrecks were documented among the findings, it would be enriching to include a paragraph that specifies:

• How the survey route was planned.
• How many square kilometres were covered and in which sectors relative to Attu Island.
• Whether historical documentation was used to guide the survey and, if so, in what way.

Part of this information is presented in the results section but does not have its counterpart in the Materials and Methods section.

5. Results

The description of both wrecks is thorough and very clear for the reader, with good support from images that allow the exposition to be followed easily.

Kotohira Maru
The description and interpretation of the SAS imagery of the Kotohira Maru is very clear and facilitates interpretation of the figure. As for the ROV photographs, the authors themselves note that they are difficult to interpret. One possibility – as a suggestion – would be to include fewer photographs but at a larger size to aid comprehension.

SS Dellwood
Required correction (lines 864–878): The paragraph in question should be reviewed, as the location of the mast bed appears to be incorrectly referenced. Given that the bow is oriented towards the west, the photogrammetry was conducted between the midships section and the stern, and the mast bed is located on the port side and to the east of the boilers, it is estimated that this feature is situated near the stern, not the bow. Since the remainder of the site description is consistent, this is assumed to be a writing error.

General suggestions for figures

• It would be advisable to include more indications of the vessel features in the SAS figures, to further aid interpretation for readers not specialised in nautical matters. One option would be to add arrows and number the points of interest in order to keep the image cleaner.

6. Discussion

This section adds historical information about both vessels, which is certainly interesting and relevant; part of it is placed in dialogue with the archaeological evidence, yielding very interesting interpretations.

However, it is not common to introduce new information in the discussion section. Consequently, most of this information (including Figure 12) should not appear for the first time in the discussion, but rather in section 3 (Vessel Narratives).

It is suggested that, in  the discussion should instead draw on that information and place it in dialogue with the archaeological evidence, for example:

• The post‑sinking activity of the SS Dellwood: possible harbour clearance.
• The incident involving the alleged sinking of the submarine at the entrance to Holtz Bay.

Final Recommendation

Recommendation: Accept with minor revisions.

The article is solid and original, and makes a valuable contribution to the field of maritime archaeology in the North Pacific. The corrections identified in the Results section (location of the mast bed), a partial reorganisation of the Discussion section, and the additional methodological details suggested should be addressed.

Author Response

Comment 1: other islands of the Aleutian archipelago are mentioned but are not referenced on the map presented in the article. It is recommended, if feasible, to include a map of the region indicating the places mentioned that are closest to Attu, especially the lesser‑known ones named in the article. This does not affect the central understanding of the text but would allow the reader to follow the reading more easily.

Response 1: We appreciate this suggestion and understand how a map indicating the other islands’ location could be a visual useful visual aid. However, we feel that this is not crucial to the manuscript and that the current map adequately depicts the relevant information while retaining sufficient resolution and context that may be lost by altering the map. Likewise, we do not believe it necessary to include a separate Aleutian Islands given the focus is almost exclusively on Attu, with the other islands being only briefly mentioned.

Comment 2: Nor has the location of the wrecks been indicated on a map; however, it is understood that the location may be considered sensitive information, so I leave this decision to the authors and editors.

Response 2: The reviewer is correct in understanding that the exact location of the wrecks is considered sensitive at the moment. The general area (Holtz Bay and Massacre Bay) is discussed in the text and the map (Figure 1) denotes the location of both bays. At present, we do not feel it appropriate to mark the exact location of the wreck sites.

Comment 3: The plans of the two ships constitute very interesting documentation and a valuable contribution. However, the limitations of the format make them difficult to appreciate. If possible – via a hyperlink – it would be advisable to present the plans at a larger size and resolution.

Response 3: For the plans of Kotohira Maru (Figure 2), a full sized image can be found following the link provided under Reference [46]. Similarly, the caption for the Dellwood plans (Figure 4) notes where the General Arrangement plans can be accessed through the National Archives according to the citation information under Reference [50]. We believe this suffices and that inserting a hyperlink into the text is not necessary given the relevant citations.

Comment 4: Given that the article represents the first remote sensing study of the submerged heritage of Attu Island, carried out over five days, and that two shipwrecks were documented among the findings, it would be enriching to include a paragraph that specifies:

• How the survey route was planned.
• How many square kilometres were covered and in which sectors relative to Attu Island.
• Whether historical documentation was used to guide the survey and, if so, in what way.

Part of this information is presented in the results section but does not have its counterpart in the Materials and Methods section.

Response 4: Thank you for pointing this out. We agree with this comment. Therefore, we have amended the Methods and Materials section to explicitly state that a desk-based assessment based on historical records, including war documents and hydrographic surveys, was carried out prior to the survey (Pages 8-9, Lines 373-400). Additionally, we have specified the area (square kilometers) surveyed for the overall survey (Page 10, Lines 452-453).

Comment 5: As for the ROV photographs, the authors themselves note that they are difficult to interpret. One possibility – as a suggestion – would be to include fewer photographs but at a larger size to aid comprehension.

Response 5: We appreciate the feedback regarding Figure 7 and have amended the figure to include 4, rather than 6, images, allowing for more clarity as to what is being seen. Additionally the caption has been updated to aid the reader’s interpretation of the imagery (Page 15, Lines 735-737).

Comment 6: Required correction (lines 864–878): The paragraph in question should be reviewed, as the location of the mast bed appears to be incorrectly referenced. Given that the bow is oriented towards the west, the photogrammetry was conducted between the midships section and the stern, and the mast bed is located on the port side and to the east of the boilers, it is estimated that this feature is situated near the stern, not the bow. Since the remainder of the site description is consistent, this is assumed to be a writing error.

Response 6: The reviewer is correct in pointing out this mistake. We have revised the paragraph in question to accurately state that the mast bed is in fact on the starboard side and not port side as the reviewer’s comment states (Page 19, Line 923).

Comment 7: It would be advisable to include more indications of the vessel features in the SAS figures, to further aid interpretation for readers not specialised in nautical matters. One option would be to add arrows and number the points of interest in order to keep the image cleaner.

Response 7: We appreciate the reviewer’s suggestion, but feel that the SAS figures are appropriately annotated as is.

Comment 8: However, it is not common to introduce new information in the discussion section. Consequently, most of this information (including Figure 12) should not appear for the first time in the discussion, but rather in section 3 (Vessel Narratives).

It is suggested that, in  the discussion should instead draw on that information and place it in dialogue with the archaeological evidence, for example:

• The post‑sinking activity of the SS Dellwood: possible harbour clearance.
• The incident involving the alleged sinking of the submarine at the entrance to Holtz Bay.

Response 8: While we respect the opinion of the reviewer, the decision to include narrative information in the discussion was an intentional one made by the authors. Prior to the survey, what was readily known about SS Dellwood was limited to what is provided in the Vessel Narrative section (3.2). It was only after the site’s discovery during the survey that a deep dive into the ship’s history was conducted. In this way, the survey not only led to a discovery of the site’s physical remains, but also to the history behind the ship. To make this point more explicit, a revisions have been made on Page 23 Lines 1121-1125. Similarly, the incident involving USS Phelps and alleged submarine at the entrance of Holtz Bay had never before been linked to the wreck of Kotohira Maru, as highlighted in the revisions made on Page 22 Lines 1082-1084. Thus, it was not until after the survey that it became apparent that the two were likely connected. The authors feel that discussing the archaeology as a mechanism for spurring new assessments of the historical record is part of the justification for conducting this type of survey. Placing the new insights regarding the vessels’ histories prior to the archaeological findings detracts from this point. The revisions mentioned in this response have been added to make clearer for why the discussion is structured this way.  

 

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript presents the results of the first systematic underwater archaeological survey of Attu Island in Alaska. The study focuses on the discovery and documentation of two significant shipwrecks from the Second World War: the Japanese army transport ship Kotohira Maru and the American cable-layer SS Dellwood. The study is highly relevant as it addresses a significant gap in the historical and archaeological record of the 'forgotten' Aleutian Campaign of the Second World War. By integrating synthetic aperture sonar (SAS), multibeam echosounder (MBES) and ROV imagery, the authors successfully located and documented the two shipwrecks, providing valuable insights into their operational roles, historical significance, preservation state, environmental challenges and connection to Attu Island's history and the displacement of the indigenous Saskinax population. 
The manuscript is technically sound and provides a significant contribution to maritime archaeology and WWII history by revealing previously undocumented events with multiple effects regarding the historic and social framework.
For the final version, the reviewer has some suggestions regarding the following:
1. The research questions should be introduced somewhere in the introduction or the Materials and Methods section.
2. It would be preferable to have more explanatory captions.
3. To achieve a more balanced approach, some ROV imagery of the SS Dellwood should also be included showing the surface condition.

Some minor changes are required:
- Line 177: Insert the source of the map.
- Line 241: Insert the source for Lloyd's Register.
- Lines 292 and 330: Insert the source for the National Archives.
- Line 894: Insert the source for EFC Design 1043.

Author Response

Comment 1: The research questions should be introduced somewhere in the introduction or the Materials and Methods section.

Response 1: Thank you for pointing this out. We agree with this comment and therefore have explicitly stated the project’s research questions in the Introduction section (Page 2, Lines 65-71).

Comment 2: It would be preferable to have more explanatory captions.

Response 2: We feel that the figure captions are sufficiently explanatory.

Comment 3: To achieve a more balanced approach, some ROV imagery of the SS Dellwood should also be included showing the surface condition.

Response 3: The decision to omit an ROV photograph was based on space constraints of the article. However, we agree with the reviewer’s comment and have added a similar panel of ROV photos for Dellwood, as was originally done for Kotohira Maru (Page 17, Line 824).

Comment 4: Line 177: Insert the source of the map

Response 4: The figure caption has been amended to accurately credit the map’s source (Page 4, Lines 182 – 183).

Comment 5: Line 241: Insert the source for Lloyd's Register.

Response 5: The reference [46] listed in the caption for Figure 2 provides the relevant source information for Lloyd’s Register via the formatting used in Heritage.

Comment 6: Lines 292 and 330: Insert the source for the National Archives

Response 6: The references for the National Archives are listed in the captions for Figures 3 and 4 via the formatting used in Heritage.

Comment 7: Line 894: Insert the source for EFC Design 1043.

Response 7: The source of the EFC Design 1043, Reference [48], is provided via the formatting used in Heritage.

Reviewer 4 Report

Comments and Suggestions for Authors

The text is well written, although the aim of the field research is not clear from the start. Was the team looking just for the two wrecks or was it a general survey of the waters around the island? Why did they choose the ships and not the airplanes? Did they find any other testimonies of the war on their surveys?

The readers are led to the two wrecks but we are not informed of the project research aims and that should be clear from the start.

Author Response

Comment 1: The text is well written, although the aim of the field research is not clear from the start. Was the team looking just for the two wrecks or was it a general survey of the waters around the island? Why did they choose the ships and not the airplanes? Did they find any other testimonies of the war on their surveys?

The readers are led to the two wrecks but we are not informed of the project research aims and that should be clear from the start.

Response 1: Response 1: Thank you for pointing this out and we agree with this comment. Therefore, we have amended the Introduction section to explicitly state the overall research question to contextualize the shipwreck sites within the larger goal of documenting Attu’s underwater cultural heritage from WWII (Page 2, Lines 65-71).

Additionally, a subsection detailing the survey planning has been added to the Materials and Methods section, which states that the two shipwreck sites were among numerous vessels sought during the survey (Pages 8-9, Lines 373-400).