At the Core of the Problem: A Bespoke Method Used to Clean the Bores of USS Monitor’s XI-Inch Dahlgren Shell Guns

ABSTRACT

When the turret from USS Monitor (1862) was recovered in 2002, it still contained the ship’s primary armament: two XI-Inch Dahlgren Shell Guns. These guns are the largest caliber smoothbore, cast iron artillery ever recovered from a marine archaeological site, and as a result of their size, weight, and fragile condition they represented a particular engineering challenge to clean. After comparing equipment used by other conservation laboratories to clean artillery bores, it was found that no existing method ideally fitted the predicted requirements set out for the guns from USS Monitor. As such it was necessary to create a new method to remove concretion from within the ship’s artillery, in order to facilitate their future stabilization and treatment. This article describes the reasoning behind the decision to create a bespoke treatment methodology, details the equipment designs and construction, and provides a case study for its operation.

RÉSUMÉ

Lorsque la tourelle de l'USS Monitor (1862) a été mise au jour en 2002, elle contenait encore l'armement principal du vaisseau : deux canons XI-Inch Dahlgren. Ces armes sont les plus gros calibres de canons à âme lisse en fonte d'acier jamais retrouvés sur un site d'archéologie sous-marine ; à cause de leur taille, poids, et fragilité, leur nettoyage représentait un défi technique. Après avoir comparé le matériel utilisé par d'autres laboratoires de conservation-restauration pour nettoyer l'intérieur de pièces d'artillerie, aucune méthode existante ne remplissait parfaitement les critères préétablis pour les canons de l'USS Monitor. Il a donc été nécessaire de créer une nouvelle méthode de retrait des concrétions à l'intérieur des canons du vaisseau, afin de faciliter leurs futures stabilisation et restauration. Cet article décrit le raisonnement qui a mené à la décision de créer une méthodologie de traitement sur mesure, détaille la conception et la fabrication de l'équipement créé, et fournit une étude de cas pour son utilisation. Traduit par Claire Cuyaubère.

RESUMO

Quando a torre do USS Monitor (1862) foi recuperada em 2002, ela ainda continha o armamento primário do navio: duas metralhadoras de 9 polegadas Dahlgren. Essas armas são a artilharia de ferro fundido de cano liso de maior calibre já recuperada de um sítio arqueológico marinho e, como resultado de seu tamanho, peso e condição frágil, representavam um desafio particular de engenharia para limpar. Depois de comparar equipamentos usados por outros laboratórios de conservação para limpar calibres de artilharia limpa, descobriu-se que nenhum método existente se encaixava idealmente nos requisitos previstos estabelecidos para as armas do USS MONITOR. Como tal, foi necessário criar um novo método para remover a concreção de dentro da artilharia da nave, a fim de facilitar sua estabilização e tratamento futuros. Este artigo descreve o raciocínio por trás da decisão de criar uma metodologia de tratamento sob medida, detalha os projetos e a construção dos equipamentos e fornece um estudo de caso para sua operação. Traduzido por Beatriz Haspo.

RESUMEN

Cuando se recuperó la torreta del USS Monitor (1862) en 2002, todavía contenía el armamento principal del barco: dos cañones de proyectiles Dahlgren de XI pulgadas. Estas armas son la artillería de hierro fundido de ánima lisa de mayor calibre jamás recuperada de un sitio arqueológico marino y por su tamaño, peso y condición frágil, representaron un desafío particular de ingeniería para limpiarlos. Después de comparar el equipo utilizado por otros laboratorios de conservación para limpiar los orificios de artillería, se descubrió que ningún método existente se ajustaba idealmente a los requisitos previstos establecidos para los cañones del USS Monitor. Por lo tanto, fue necesario crear un nuevo método para eliminar la concreción del interior de la artillería del barco, con el fin de facilitar su futura estabilización y tratamiento. Este artículo describe el razonamiento detrás de la decisión de crear una metodología de tratamiento personalizada, detalla los diseños y la construcción del equipo y proporciona un estudio de caso para su operación. Traducción: Amparo Rueda.

KEYWORDS:

• Archaeological
• objects
• cast iron
• marine
• cleaning
• artillery
• concretion
• cannon

SOURCES OF MATERIALS

72” M-2 Drill Track,

M-2 Roller Carriage Assembly,

Weka DK-22 230 V Drill Motor

Diamond Products Limited 333 Prospect St.

Elyria, OH 44035 USA Tel: [phone]

Fax: [phone] https://www.diamondproducts.com

BJ-6 and MJ-6 Screw Jacks

Ellis Manufacturing Co., Inc.

4803 N Cooper Ave.

Oklahoma City, OK 73118 USA

Tel: [phone]

Fax: [phone]

Email: [email protected]

https://ellismanufacturing.com/collections/screw-jacks/products/ellis-bridge-jack?variant=2271983873

Fowler 54-440-600 Electronic Level

Fowler High Precision

780 Dedham St.

Canton, MA 02021 USA

Tel: [phone]

Fax: [phone]

Email: [email protected]

http://www.fowlerprecision.com/Products/Electronic-Protractors/544406000.html

Heechoo 200 kg Capacity 800 mm Travel Linear Slide Table

Amazon.com

https://www.amazon.com/Sliding-Travel-Length-Ballscrew-Handwheel/dp/B07T9F8DSH

Universal Wall Saw Mounting Bracket

Husqvarna

Tel: [phone]

https://www.husqvarnacp.com/us/accessories/attachments/mounting-bracket-universal/531113200/

Standard and Custom-Sized Coring Bits

KOR-IT

Tel: [phone]

Email: [email protected]

https://www.kor-it.com/product/superior-brandclosed-end-bits

Acknowledgements

Many thanks to the entire team at The Mariners’ Museum and Park who assisted with building and operating this system, and with documenting the Dahlgrens’ cleaning. A tremendous group effort across multiple departments was required to make this process work, and every person involved was vital. Additional thanks go out to Master Machine and Tool for their design and fabrication, and to the museum’s donors and funding institutions for making this work possible.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Erik Farrell

Erik Farrell is an objects conservator at The Mariners’ Museum and Park in Newport News, VA. There he has worked on objects recovered from the wreck of USS Monitor (1862) and within the Museum’s non-archaeological collections. He received his Master’s in Conservation of Archaeological and Museum Objects from Durham University. Address: 100 Museum Dr., Newport News, VA 23606, USA. E-mail: [email protected]