Part 1: Introducing the bolt
This is part one of a story about a simple, copper-alloy fastener that has implications much larger than its simple form might betray.
In 2010, I was working as a Graduate Research Assistant in the New World Lab as part of my studies in the Nautical Archaeology Program at Texas A&M University. As often happened during the afternoon, I was approached by our director, Dr. Crisman, and given a book with several sticky notes marking specific pages. He had been e-mailing with a gentleman [Mr. P.] who had contacted him for assistance in identifying an “object” (Fig 1.) and he wanted me to scan a reference and send it to Mr. P.
Fig 1. The “Object”: A copper alloy bolt for fastening ship timbers – Click to Englarge (Photo by H. Jones)
The “object” turned out to be a bent, copper alloy bolt with a washer. I was unfamiliar with this style of fastener and found the description that Dr. Crisman sent to the gentleman too perfect to rework:
“A bolt like that would be used to fasten together ship’s timbers, something like a floor timber from a frame to the keel, or perhaps to secure a plank butt to a frame so it did not spring loose. Your bolt is likely from the 1800s or very early 1900s. The Royal Navy began using copper fasteners in the 1780s, and by the nineteenth century they were increasingly common in merchant ships, too, especially once inventors came up with alloys that cheapened their cost by mixing less expensive metals (zinc, for instance) with the expensive copper. The use of copper alloy bolts and spikes was made necessary by the use of copper sheathing to protect wooden ship timbers from being invaded by teredo worms. Iron fasteners dissolved due to electrolytic action with the copper in the surrounding seawater. Copper alloy bolts were more expensive and did not hold as well as iron, the bolts had to be headed (mushroomed) over washers to ensure a tight hold, like on your example. The copper bolts or spikes would only be used below the water line where the hull fasteners would be in contact with the sheathing.” – Dr. Crisman, Personal Correspondence Feb 7, 2010.
In addition to this description, the reference Dr. Crisman had me send Mr. P. was an image from “The American Built Clipper Ship 1850-1856” by William Crothers (Fig 2.).
Fig 2. Example of the bolt style outlined in red – Click to Enlarge (from Crothers 2000, Fig 4.1)
Once the gentleman knew a bit more about the bolt he mailed it to our lab as a donation, for use as a teaching aid in a regularly taught class on the outfitting and rigging of wooden ships. When the bolt arrived at our lab, Dr. Crisman passed it into my hands for conservation.
Besides the what I had learned from Dr. Crisman and William Crother’s publication, the only other information I had about the bolt was that was recovered by the first husband of Mr. P’s wife, while he was diving off the Florida keys from 1984-5. Part of conservation is not only stabilizing artifacts, but researching their history. In this case, my goal was not only to conserve the bolt and prepare it for use in the rigging class, but use the conservation process to search for any further information about the bolt, such as a maker’s mark.
To Be Continued…
But it’s only a bolt…Right? [Part 2] : Conserving the Bolt.
Crothers, w. 2000. The American-built clipper ship, 1850-1856. Camden, ME: International Marine.