Citation: Mason, B.; Finch, J.; Paynter, S.; Anderson, H.; Nagler, L. Curved Linear Diode Array Imaging of a Historic Anchor Recovered from East Anglia ONE Offshore Wind Farm. Heritage 2024, 7, 2552–2568. https:// doi.org/10.3390/heritage7050122 Academic Editors: Silvano Mignardi, Wenke Zhao, Laura Medeghini, Melania Di Fazio and Laura Calzolari Received: 20 March 2024 Revised: 9 May 2024 Accepted: 10 May 2024 Published: 16 May 2024 Copyright: © 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). heritage Article Curved Linear Diode Array Imaging of a Historic Anchor Recovered from East Anglia ONE Offshore Wind Farm Brandon Mason 1, *, James Finch 2 , Sarah Paynter 3 , Heather Anderson 1 and Lauren Nagler 1 1 Maritime Archaeology Trust, Southampton SO14 3ZH, UK; heather.anderson@maritimearchaeology.co.uk (H.A.); lauren.nagler@maritimearchaeology.co.uk (L.N.) 2 Nikon Metrology UK, Tring HP23 4JX, UK; james.finch@nikon.com 3 Historic England, Portsmouth PO4 9LD, UK; sarah.paynter@historicengland.org.uk * Correspondence: brandon.mason@maritimearchaeology.co.uk Abstract: The Industrial Metrology Business Unit of Nikon Corporation, on behalf of ScottishPower Renewables and Maritime Archaeology (MA), Southampton, UK, has employed X-ray CT (computed tomography) to visualise the internal structure of an anchor found in the North Sea. The non- destructive method of internal inspection and measurement has helped to determine approximately when it was made. The results indicate that the artefact, initially thought to be potentially Roman, is probably more recent, likely dating to between the late 16th and early 17th centuries CE. This paper presents the discovery, recovery, analysis and interpretation of a significant find from a UK offshore wind farm and underscores the valuable role that non-destructive X-ray CT played in the investigation. Keywords: anchor; artefact; forging; inspection; iron; measurement; museum; non-destructive; stabilization; X-ray CT; diode array 1. Introduction Anchor WTG_D_154 was discovered 60 km offshore at a depth of 40 m during re- motely operated underwater vehicle (ROV) investigations prior to the development of ScottishPower Renewables’ East Anglia ONE offshore wind farm off the coast of Suffolk, UK, in 2018 (Figure 1). The iron anchor, an isolated find, had typological similarities to a late Iron Age example recovered from Bulbury Camp, Dorset, in the 19th century [1,2] as well as other features similar to Roman examples from the 1st–2nd century AD [3,4]. Due to the possible archaeological importance of the anchor, a conservation manage- ment plan and long-term care strategy was agreed with Historic England and the anchor was subsequently recovered by ScottishPower Renewables during an archaeological inter- vention [5]. Dating iron objects is notoriously difficult. Some information can be gained through taking samples from the object for metallography to look for evidence of welds and how the object was constructed. Chemical analysis of the small inclusions of slag waste left in the metal, from when it was smelted or refined, can also indicate the type of fuel used (charcoal or coke) and so suggest a possible date range [6]. Sometimes there is enough carbon in the iron itself to attempt radiocarbon dating [7]. All these methods require samples to be taken, and as it was agreed prior to recovery that the anchor would eventually go on public display, a non-destructive investigative programme of analysis was developed to try to illuminate the mode of construction and the individual elements that comprise the internal structure. The way that an anchor is constructed provides a possible indication of when it was made. Anchors are typically made from multiple pieces of iron that have been joined together; however, the size and shape of the individual iron pieces, or units, and how these are assembled, tend to change over time. With more developed iron smelting, refining and Heritage 2024, 7, 2552–2568. https://doi.org/10.3390/heritage7050122 https://www.mdpi.com/journal/heritage