Advanced Technologies for Maritime and Underwater Archaeology—2nd Edition

1. Introduction

Underwater cultural heritage (UCH) is one of the richest and most vulnerable records of humankind’s past. Shipwrecks, submerged settlements, and harbours preserve unique evidence of ancient trade, navigation, and coastal life, yet they lie in environments that are difficult to access and are increasingly exposed to natural deterioration, human pressure, and the accelerating effects of climate change [1,2]. Protecting this heritage, and keeping it accessible to present and future generations, requires documenting it as accurately and as non-intrusively as possible, a principle explicitly promoted by the 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage through its emphasis on non-destructive techniques and in situ conservation [3,4]. Meeting this goal is an interdisciplinary endeavour that brings together archaeology, geology, biology, marine science, conservation, engineering, robotics, and computer science.

In recent years, the field has been reshaped by rapid technological progress. Acoustic and geophysical methods, such as the synthesis of bathymetric and marine geophysical datasets in common three-dimensional (3D) platforms [5,6], together with sub-bottom profilers, multibeam and side-scan sonar, and autonomous underwater and surface vehicles (AUVs and USVs) [7,8], now allow large areas of the seafloor to be surveyed and documented at high resolution, with few constraints related to water depth. At the same time, underwater photogrammetry provides detailed and accurate 3D models that support both research and long-term monitoring [9,10].

In parallel, dedicated underwater tools and robotic systems support in situ conservation and the maintenance of submerged structures [11,12], and digital technologies are enabling underwater sites to be opened for sustainable and responsible tourism [13,14]. At the same time, frontier technologies such as the Internet of Underwater Things (IoUT), Edge Computing (EC), and Artificial Intelligence (AI) are transforming how UCH is monitored and managed. AI is becoming central to this area since it supports the detection and classification of features of archaeological interest, the fusion and interpretation of heterogeneous sensor data, and the identification and assessment of risks that environmental change and human activity pose to submerged sites.

Together with new methods for assessing the impacts of climate change on shallow-water cultural heritage, these advances are redefining the scope of what can be documented, understood, and preserved underwater.

2. Overview of Contributions

This Special Issue is the second edition of “Advanced Technologies for Maritime and Underwater Archaeology”, building on the success of its first edition [1]. It brings together original and high-quality research articles and technical notes devoted to the study, documentation, and conservation of underwater cultural heritage. The collection promotes innovative methodologies, applications, and emerging technological solutions for investigating, monitoring, and preserving archaeological materials, sites, and cultural landscapes located in underwater environments. The eight contributions collected here were selected from a larger pool of submissions and cover a broad range of underwater cultural heritage contexts, including shipwrecks, submerged harbours, and coastal environments. They also showcase diverse technologies, from acoustic and remote sensing surveys to AI, photogrammetry, and the assessment of climate change impacts on submerged cultural heritage.

Calantropio and Chiabrando (2024) (contribution 1) provide a comprehensive review of underwater photogrammetry for the documentation of underwater cultural heritage, currently the most widely used metric technique thanks to its non-destructive and relatively inexpensive nature. The authors discuss the production of high-resolution 3D models and 2D orthomosaics for monitoring, conservation, expert study, replica reproduction, and dissemination, while addressing the specific challenges posed by the optical properties of water, light penetration, visibility and suspension, and radiometric issues.

Helfman et al. (2024) (contribution 2) revisit the sail plan of the 11th-century Serçe Limanı ship. Using computational fluid dynamics and hydrostatic stability analysis to evaluate hull resistance, sail propulsion, and heeling moments, the authors reassess the previously proposed double-masted rig and investigate an alternative single-sail configuration. Their results indicate that a sail area of at least 150 m² would have been required to propel the vessel, leading to the selection of a feasible single-sail rig as an alternative reconstruction.

Galili et al. (2024) (contribution 3) develop a methodological framework to distinguish anthropogenic features from natural formations in submerged landscapes. The framework integrates geological and geomorphological evidence, sea-level reconstructions, associated archaeological remains, the broader archaeological context, and direct visual inspection by underwater archaeologists. Applying these criteria to two previously published case studies in the Sicilian Channel, the authors conclude that the investigated features are more plausibly attributable to natural processes than to human origin, and stress that remote sensing cannot substitute in situ verification.

Herrera-Santos et al. (2024) (contribution 4) propose an architecture that combines the IoUT and EC for the real-time monitoring, localization, and management of UCH. Data are processed by a central unit installed on a buoy near the heritage site, and the integration of acoustic communication systems, LoRa technology, and non-terrestrial networks, together with AI models deployed at the edge node, enables continuous risk assessment even in remote maritime areas and without relying on cloud connectivity.

Ferrero-Martín et al. (2025) (contribution 5) describe a new methodology to assess the impact of climate change on the preservation of underwater cultural heritage in shallow waters, focusing on wave-induced hazards such as decontextualization, scouring, and wear erosion. Applying hybrid downscaling of bias-corrected wave fields under the RCP4.5 and RCP8.5 climate scenarios, the authors evaluate future risk patterns in the Bay of Cádiz. Their results indicate that, despite an overall reduction in wave energy flux, local increases at rocky outcrops may significantly alter hazard levels, with wear erosion emerging as the most affected risk factor.

Gambash et al. (2025) (contribution 6) report on high-resolution multimodal remote sensing surveys conducted at the sunken Herodian harbour of Sebastos, in the Roman city of Caesarea Maritima. Using diver-based photogrammetry to generate a detailed 3D reconstruction of the harbour entrance, the authors identify two distinct architectural styles on either side of the channel, suggesting different building phases and a possible later renovation. The study provides new insights into the development, operation, and progressive deterioration of one of the largest artificial harbours of the Roman period.

Benetatos et al. (2025) (contribution 7) present the first underwater survey of a 1st-century B.C. Roman shipwreck located off Santo Stefano al Mare, in the Ligurian Sea (Italy), carried out with an autonomous underwater vehicle (AUV). Equipped with a multibeam echosounder, a side-scan sonar, and inertial navigation systems, the AUV acquired high-resolution bathymetric and acoustic data that were subsequently analysed using geospatial techniques. The results revealed a clearly defined assemblage of amphorae and other seabed anomalies directly associated with the wreck, demonstrating the effectiveness of integrating AUV technologies and spatial analysis methods for underwater archaeological investigations.

Solana Rubio et al. (2026) (contribution 8) assess the use of a high-resolution sub-bottom profiler (SBP) as a non-intrusive technique for surveying and documenting UCH in different regions of Spain. Through a series of geophysical surveys conducted under varying depths and environmental conditions, the authors evaluate the effectiveness of a SBP for underwater archaeological investigations. The study highlights its potential to document submerged heritage without disturbing the remains, in line with the principles of non-destructive documentation and in situ conservation promoted by the 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage.

3. Conclusions

This second edition of the Special Issue “Advanced Technologies for Maritime and Underwater Archaeology” illustrates both the breadth of UCH and the rapid evolution of the technologies used for its exploration and documentation. Most of the contributions present remarkable case-studies that span a wide range of sites and environments, from Roman shipwrecks in the Ligurian and Mediterranean seas to the Herodian harbour of Caesarea, prehistoric submerged landscapes in the Sicilian Channel, and heritage along the Spanish coast. At the same time, these contributions cover an equally wide methodological spectrum, from acoustic and geophysical surveying with sub-bottom profilers to autonomous underwater vehicles, high-resolution photogrammetry, and 3D reconstruction. Moreover, the growing role of AI, together with the IoUT and EC, is enabling the capture and processing of heterogeneous sensor data, the detection and classification of features of archaeological interest, and the assessment and mitigation of risks affecting underwater cultural heritage.

We expect these directions to shape the next stage of research in maritime and underwater archaeology. We hope that this Special Issue contributes to that effort and inspires further work across the many disciplines that this field brings together.