Another Link in the Chain: Archaeometallurgical Investigation of an Anchor Chain from the Nineteenth Century Akko Tower Shipwreck

Abstract

In the 2016 excavation season of the Akko Tower shipwreck, a ferrous stud-link anchor chain and a rod, both covered with thick encrustation and concretion, were retrieved from the site. The chain links, studs, and rod were analyzed by metallurgical methods, including: radiographic testing, x-ray fluorescence, light microscopy, scanning electron microscopy with energy-dispersive spectroscopy, optical emission spectroscopy, and microhardness measurements, in order to determine their composition and microstructure. The links and the rod were made of wrought iron, while the studs were made of gray cast iron with a significant silicon content of 2 wt.%. The welding zone of the links was identified. The chain was end-welded by forge welding, and the stud was fixed mechanically. The design and manufacturing characteristics of the chain are typical of nineteenth century stud-link anchor chain, which supports the dating of the ship. It is suggested that the chain served the secondary anchor of the ship.

Reused and Recycled. Archeometallurgical Study of Historical Nails Found in Guam, Mariana Islands, Western Pacific

“…After forging, recrystallization takes place, which explains the large amount of equiaxial ferrite in the microstructure. However, the slag does not recrystallize at those temperatures, and the grains may have adopted a shape that evidences the hot work (Cvikel et al 2013;Iddan et al 2020). The slag that is present is very similar to what was presented in the Buchwald and Wivel study, which is a wüstite and glass slag (Buchwald and Wivel 1998).…”

The Production of Marine Iron Objects in Europe Following the First Industrial Revolution: The Akko Tower Shipwreck Test Case

“…Cast defects, such as rounded cavities and interdendritic porosity, were observed by VT on the surface of the winch drum and the stud-link chain controller, indicating that these two items were cast products [31,33]. Straight parallel lines were observed by VT on the external surface of the winch shaft, the heart-shaped shackle, and the deadeye strap with a futtock plate, showing that these items were wrought iron products worked by plastic deformation [12] (p. 215, Figure 3).…”

“…Description of the ferrous objects and their characterisation method. The winch, the heartshaped shackle, the deadeye with a futtock plate, and the stud-link chain controller were currently studied, whereas deadeye 163B, deadeye 164 chain links [9,19], and the anchor chain link and stud [12] were studied previously. The + sign represents tests that were performed and the − sign represents tests that were not.…”

“…Stud-link chain controller (Figure 1d and Supplementary Material Figure S1b) was possibly used to support the anchor stud-link chain [12]. This item weighed 12 kg and was 405 mm long, 81 mm wide, and 135 mm high; the arc thickness varied between 40 and 70 mm.…”

“…The characteristic microstructure of wrought iron items produced by the 'puddling' technique contains elongated slag inclusions surrounded by a ferritic iron matrix. The preferred orientation of slag inclusions indicates the direction of plastic deformation in the forging process [9,12,19]. Until the development of the Bessemer process in 1856, wrought iron was produced either by the direct or the indirect smelting technique [16,19,[24][25][26].…”