The CDSG now has digitized a fairly complete set of Engineer documents on the harbor defense structures of the United States Army. The data sets available have been broken down by the various harbor defenses in the third section so you can order sets of records by coast/harbor defense, or get the complete collection. This is a very good collection of historical information on the harbor defense structures: batteries, fire control, mine support, searchlights, etc., built at the various harbor locations.

PDF listing of all Harbor Defense Document files

Reports of Completed Works (RCWs)

Reports of completed batteries (RCBs) and reports of completed works (RCWs) were forms used by the Corps of Engineers to document seacoast fortifications and other structures related to coast defense. RCBs were in use from 1900 until 1919. RCWs were in use from 1919 until the coast artillery was disbanded in 1950. Both are essential documents in the study of modern U.S. coast defenses, 1890-1950.

From 1903 to 1919 the RCB was used to compile information on the batteries located at specific harbor defenses, including the official name of each batteries, the individual number and name of the manufacturer of each gun or mortar and carriage with the number of the emplacement each gun or mortar and carriage was mounted in. RCBs were submitted annually.

Reports of completed works (RCWs) were a new set of forms that superceded the RCBs in 1919. It prescribed that all data in the RCBs would be submitted on seven forms referred to as reports of completed works. Furthermore, new forms need only be submitted whenever changes in works made the old forms obsolete, compared to the annual submission of RCBs.

The seven forms were:
Form 1 all important data relating to an individual battery
Form 2 details of fire control and torpedo structures
Form 3 details of mine wharfs and tramways
Form 4 details of searchlights (a separate sheet for each light)
Form 5 details of electric plants
Form 6 existing Engineer Dept structures of permanent or semi-permanent nature
Form 7 a blueprint of the battery

The big scanning project of all of the coast artillery RCBs and RCWs is now complete. A first generation copy set of over 12,000 pages— nearly all the RCBs and RCWs available at NARA II— have been scanned and digitized as PDF pages. This will be the most extensive collection of RCBs and RCWs available. The documents are organized by harbor defense and broken down into two or more files by harbor (RCBs) and fort/location (RCWs) depending on the number of pages. Each document contains a series of grey-scale images of each of the RCB/RCW forms in the collection related to each harbor defense. Grey scale was chosen because black and white scans could not sufficiently resolve the “negative” forms and give a legible printout. The grey scale scans are at 200 dpi, which gives a bigger file size than black and white but with sufficient resolution to make a readable copy. The PDF documents are essentially a series of electronic photocopies, and as such the files are NOT text searchable, so a researcher will have to scroll through each file to find the pages of interest. The RCB collection has been added to each harbor defense collection.

Total: 120 files, 12,000 plus pages, 28 GB

Engineer Notebooks 1900-1928

The engineer assigned to each harbor defense kept a notebook on the defense structures that were located in a given harbor defense. They maintained a ledger, a journal, and memorandum log for the batteries, the fire control structures, the electrical generators, the searchlights, the torpedo (mine) structures, and in some cases, the land defenses. A fairly complete set appears to have been collected around the mid-1920s and is now housed in the National Archives. These have been copies and scanned as PDFs. These notebooks have information on when the structures were built, but more importantly information on modifications and changes to these structures over the years, for instance, we can see what guns were removed from what battery during 1917-18. The notes show that both Los Angeles, CA, and Guantanamo Bay, Cuba, had a complete set of structures built for the control of mine fields, even though the mines were not deployed at these locations. These are a great source of additional information on the Endicott and Taft era fortifications.

Total: 30 files, 2600 pages, 2.63 GB

Battery Construction Correspondence files:

The battery construction correspondence files, which were copied from the National Archives by Glen Williford. Over 7400 pages of material were copied. The files are arranged by battery and fort, but of course in most cases the battery was not yet named, and so the text usually just referred to as to gun size, location, or chronologically sequenced order. Sometimes there are multiple entries for a battery, particularly when an emplacement for an additional gun(s) was made after several years. Sometimes two similar or immediately adjacent batteries were authorized simultaneously, submitted simultaneously, and share a single battery file number. Also several emplacement projects were authorized and plans submitted, but for one reason or another were never constructed. These were collected and are included but usually just referred to as “projects.” In later years, separate projects were authorized for major rebuilding of older emplacements, treated administratively as “new” projects. Some battery emplacement submission records are missing in the original files. In every attempt they were searched for, and while a couple may have been missed or are misfiled and were not found, in most cases they are just “gone” or were never submitted. Many of the early Taft-generation works for the Philippines and Hawaii do not have substantial primary files and are poorly represented in the existing documentation. The period covered is generally from 1895 to 1930.

650 MB, 300 files

Inspection Reports:

PDF scans of the inspection reports for the various harbor defenses and forts from around 1900 up to 1941, the number of inspections can vary considerably from a few pages to a large number of reports. Part of the issue is that it appears that these inspection reports may be either housed in different NARA locations and others may be missing. Still the collection does provide some insight into the goings on at these locations. The collection is organized by harbor defense but may not be sequential.

650 MB; 24 files