Search Results (180)

A rare carved lacquer (tixi) plate recovered from the Southern Song Dynasty Nanhai No. 1 shipwreck was examined to reconstruct its coating stratigraphy, raw materials, and manufacturing sequence. Detached fragments collected before conservation treatment were investigated by cross-sectional optical microscopy, micro-Raman spectroscopy, thermally assisted hydrolysis–methylation pyrolysis–gas chromatography/mass spectrometry (THM-Py-GC/MS), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and wood-anatomical microscopy. The polished cross-section contains nine lacquer layers with a combined thickness of 387.3 μm above a heterogeneous ground, yielding ten visually distinguishable strata. Alternating dark, red, and yellow layers establish the technological basis for the carved polychrome effect. Raman bands identify cinnabar (HgS) in the red layer and orpiment (As₂S₃) in the yellow layer. THM-Py-GC/MS detected homologous alkenes, alkanes, and alkylbenzenes diagnostic of Chinese lacquer derived from Toxicodendron vernicifluum. Monocarboxylic acids were present, whereas no clear dicarboxylic-acid markers of a drying oil were observed; because the object was waterlogged and degraded, this absence is treated as a lack of positive evidence rather than proof that oil was never used. The ground is enriched in Ca and P and is therefore consistent with a bone-ash-based filler, although phase-specific confirmation remains necessary. Wood anatomy identifies the substrate as Chinese fir (Cunninghamia lanceolata, Cupressaceae). Together, the results document an organic–inorganic multilayer coating system and provide material evidence for Southern Song carved-lacquer technology, while defining conservation risks associated with a waterlogged wooden core and light-sensitive pigments. The marine archaeological context and the support-to-surface, layer-resolved design distinguish this case from most previous studies of Song-dynasty lacquerware. Beyond technological reconstruction, the findings identify conservation priorities for waterlogged wood, the wood–ground–lacquer interface, and light-sensitive pigmented layers, and provide a transferable evidence framework for comparative research on archaeological lacquer. Full article

The identification of visible submerged hazards, including shallow-water shipwrecks and associated debris, is important for maritime safety, coastal management, environmental monitoring, and marine archeology. The scope is restricted to wrecks that remain optically visible from above in shallow or intertidal water. This study presents Submerged Hazard Identification and Processing using Augmented Image-based Detection (SHIP-AID), a modular GeoAI evaluation framework for high-resolution RGB imagery. Following site-level quality control, the independent source dataset contains 695 images from 403 wreck sites. The dedicated group-disjoint holdout contains 150 images from 88 sites and 184 annotated wreck objects. Five detector backbones and one task-aware underwater-enhancement baseline were evaluated using ten matched training seeds. Under the standard benchmark evaluation protocol, in which precision and recall are reported at the internally determined maximum-F1 point of the confidence sweep, the best configuration achieved precision 0.896, recall 0.861, mAP@50 0.927, and mAP@50–95 0.668 on the locked holdout. At the fixed, validation-selected operating threshold of 0.45, the primary detector produced threshold-specific precision 0.922 and recall 0.837. Site-clustered bootstrap intervals were 0.895–0.951 for mAP@50 and 0.625–0.704 for mAP@50–95. Physically informed attenuation and backscatter augmentation improved stricter-IoU performance relative to generic augmentation, whereas global Otsu thresholding reduced recall and localization accuracy. Performance remained stable under mild degradation, declined under moderate and strong degradation, and became unreliable under severe low visibility. SHIP-AID is therefore positioned as a decision-support framework for prioritizing optically visible shallow-water sites, with sonar, diving, hydrographic, or archeological evidence retained as the confirmation standard. Full article

The search and discovery of underwater shipwreck sites represent the most arduous and critical phases of underwater archaeology. Wooden shipwrecks, in particular, are characterized by low acoustic impedance contrast and weak magnetic anomalies, coupled with their limited physical dimensions. Consequently, they predominantly exist as shallow-buried, discontinuous small targets scattered within confined areas, making their detection exceptionally challenging. Furthermore, the complexity of the submarine environment—including rugged topography, turbid water columns, and strong currents—poses formidable obstacles to the effective detection of these archaeological remains. Single geophysical methods are often limited by insufficient imaging resolution, interpretation ambiguity, and geological noise, making precise localization and characterization difficult. Focusing on the Nan’ao I Ming Dynasty shipwreck located in waters approximately 24 m deep off the coast of Nan’ao, Guangdong Province, China, this study proposes and validates an “acoustic-magnetic” multi-source data integration detection method. This approach systematically integrates high-resolution multibeam echo sounding (MBES), side-scan sonar (SSS), sub-bottom profiling (SBP), and marine magnetic data to establish a comprehensive framework for identification and integration analysis. The results indicate that the MBES bathymetric data reveal a regular, elongated structure oriented north–south (approximately 34 m × 12 m), closely matching the main hull and deck configuration. The SSS imagery exhibited high backscatter intensity and parallel linear textures, effectively delineating the hard shipwreck structure and the associated rigid protective frame employed for in situ preservation. SBP data confirmed the semi-buried state of the shipwreck (burial depth of approximately 0.6 m). Spatial variations in sediment thickness around the site suggested ongoing modification by strong hydrodynamic processes. Marine magnetic surveys identified localized negative anomalies (−210 nT relative to the ambient magnetic field), contrasting sharply with the positive anomalies of the surrounding natural reefs, thereby indicating an artificial ferromagnetic source. The spatial registration and feature superposition of multi-source data facilitated the characterization of the shipwreck, demonstrating its potential to mitigate environmental interference and enhance detection reliability in this complex environment. Using the Nan’ao I shipwreck site as a case study, this study provides a detailed characterization of the site’s 3D morphology, burial state, and physical properties. The proposed methodology offers a practical and robust technical solution for underwater shipwreck archaeology in complex nearshore environments, providing significant implications for proactive discovery, efficient investigation, and protection of underwater cultural heritage (UCH). Full article

In November 1916, the Imperial German Navy conducted an ambitious raid against the Russian forces in the Baltic Sea. With the aim of attacking Russian ships in the coastal waters of Estonia, a squadron was dispatched from Libau. The operation proved to be very costly, with seven ships sunk by Russian mines and only minimal damage caused to the port of Paldiski. In 2025, the Estonian Maritime Museum conducted a survey of three of the seven Imperial German Navy large torpedo boats sunk north of Hiiumaa island in Estonia. The aim was to identify the wrecks and determine the potential threat the wrecks may pose to the environment from the fuel oil the boats carried. The assessment was time critical as the wrecks had sunk more than a hundred years ago, and due to the location, any oil spill from the wrecks could potentially impact Estonia, Finland, and/or Sweden. The research concluded that all three surveyed wrecks could still contain substantial amounts of fuel oil, and although the wrecks are not leaking and the collapse of the wrecks is not considered imminent, the risk mitigation should be carried out as soon as possible; the possibility for successful oil removal diminishes every year as the wrecks corrode and disintegrate. Full article

The preservation of submerged cultural heritage depends on the ability to locate, document, and monitor sites before they are degraded or lost. Although the North American Great Lakes contain thousands of exceptionally well-preserved shipwrecks, their large geographic extent and diverse operating environments present significant challenges for efficient archeological survey. This study presents a multi-platform autonomous survey framework developed and implemented during 2021–2022 field campaigns in Lake Michigan and Lake Ontario. The framework integrates autonomous underwater vehicles (AUVs), autonomous surface vehicles (ASVs), crewed vessels, side-scan sonar, multibeam bathymetry, magnetometry, optical imaging, and field-based data review within a hierarchical workflow comprising wide-area assessment (WAA) reconnaissance, high-resolution geophysical (HRG) mapping, adaptive mission refinement, and visual confirmation. The surveys produced 19.72 km² of geophysical coverage, including side-scan sonar mosaics, bathymetric surfaces, magnetic anomaly maps, and optical imagery that supported archeological interpretation. A case study from Lake Ontario demonstrates the framework’s effectiveness through the confirmation of a previously undocumented wooden shipwreck using complementary acoustic, magnetic, and visual datasets. Beyond the individual discoveries, the results demonstrate how integrated autonomous systems improve survey efficiency, support adaptive decision-making, and provide scalable methods for digital documentation, baseline site characterization, long-term monitoring, and preservation of submerged cultural heritage in freshwater and marine environments. Full article

The Makara, a potent hybrid guardian figure from Indian architectural sculpture, poses a question for the study of artistic exchange: how did this complex motif travel across Asia and transform into a simplified painted emblem on Chinese export ceramics? We address this question by analyzing a corpus of textual sources, sculptural reliefs, and ceramic assemblages, with a focused case study on ninth-century Changsha kiln production and the pivotal evidence from the Belitung shipwreck. The analysis reveals a profound morphological and functional shift. In stone, the Makara appears as a powerful, three-dimensional guardian in complex crocodilian or elephantine forms. In contrast, on mass-produced Changsha bowls, it is abbreviated to a stylized, two-dimensional head, often paired with a pearl. We argue that this transformation was not a simple degradation but a sophisticated act of modular translation. The shift in medium from stone carving to swift underglaze painting and the demands of a global market forced a functional reinvention: the static, architectural guardian became a portable, commercial emblem. Ultimately, the analysis frames the Changsha artisan as an active cultural translator and the Makara bowls as an early, successful example of customized export design for a global audience. Full article

The accumulation of shipwrecked wood in coastal ecosystems represents an important environmental challenge due to its effects on coastal dynamics, ecosystem functioning, and waste management. The valorization of this lignocellulosic residue through thermochemical conversion offers a sustainable alternative for transforming an underutilized biomass into value-added products. This study evaluated the potential of biochar produced from shipwrecked wood collected in the Punta Roca sector, municipality of Puerto Colombia (Atlántico), as an organic soil amendment. The methodology included the physicochemical characterization of the biochar, as well as analysis of its specific surface area (BET), morphology (SEM), and elemental composition (EDAX). Among the most relevant physicochemical results, the biochar exhibited an organic matter content of 87.85%, an alkaline pH of 10.29, and low moisture content (9.21%), suggesting stability and the capacity to modify soil acidity. Regarding specific surface area, the BET area increased significantly from 0.77 m²/g in untreated wood to 61.61 m²/g in the biochar, indicating a notable enhancement in adsorption capacity. Porosity analysis revealed a decrease in pore size, which may favor the retention of nutrients and water. Elemental composition analysis revealed a high carbon content (82.65%) and oxygen content (15.32%), accompanied by trace amounts of elements such as Na, Mg, Si, Cl, K, and Ca. These results confirm that biochar derived from shipwrecked wood possesses physicochemical characteristics suitable for application as an organic amendment in agricultural soils. Overall, these findings demonstrate that biochar derived from shipwrecked wood is a promising alternative not only as an organic soil amendment but also as a strategy for coastal waste valorization, the promotion of circular economy principles, and the development of more sustainable agricultural systems. Full article

Autonomous Underwater Vehicles (AUVs) equipped with multibeam echosounders (MBESs) are deployed in oceans in expeditions worldwide to find shipwrecks, as they can survey the seafloor at the resolution required to identify such objects. Due to the severely constrained acoustic bandwidth of underwater communication, it is fundamental to transmit compressed information between the AUV and the support vessel when objects of interest are detected during a mission. This paper presents a systematic evaluation of six YOLO-based configurations combining three architectures with two optimizers, along with selected hyperparameters and bathymetric visualization methods, to identify the optimal model for shipwreck detection suitable for deployment on a deep-water AUV. Such an application has the potential to optimize mapping operations, allowing the mission to be terminated early or to employ adaptive route replanning to maximize survey efficiency. We developed and evaluated an object detection model trained on high-resolution shallow-water open-source data, identifying over 630 shipwrecks along the coast of England to fine-tune the model. Six experiments were conducted and compared across the three most recent YOLO architectures by Ultralytics (v8, v11, v26) and specific hyperparameter configurations. The best-performing model achieved scores above 0.91 in precision, recall, F1, and mAP50, while successfully detecting all prominent shipwrecks in the dataset. Three additional models trained on different data visualizations (hillshade, color scale, shaded relief) demonstrated similar performance. The best-performing model was further tested on a small AUV dataset from the Gulf of America, where it successfully detected the shipwreck in deep-water. Full article

Gray siliceous concretions represent the most ubiquitous surface deposits on marine-excavated ceramics from the Nanhai No. 1 shipwreck. These concretions obscure decorative motifs and glaze surfaces of the artifacts, posing challenges to archeological interpretation and heritage conservation. This study conducted a multi-technique characterization of one representative gray siliceous concretion using micro-CT, PLM, SEM-EDS, XRD, FTIR, and micro-Raman spectroscopy. The concretion exhibits distinct three-tier density stratification and consists of quartz, muscovite, calcite, pyrite, and Mg-rich authigenic silicates (serpentine and talc), with quartz and muscovite as the dominant crystalline phases. Its mineral components are inferred to originate from terrigenous clastic, biogenic, and authigenic sources. This work provides fundamental mineralogical data to support the development of targeted conservation strategies for analogous marine-excavated ceramic heritage. Full article

Irregular migration across the Mediterranean Sea causes thousands of deaths annually, mostly due to shipwrecks involving structurally inadequate vessels navigating under severe meteo-marine conditions. The forensic investigation of human remains recovered in such contexts is particularly challenging due to advanced decomposition and the absence of documentary evidence linking victims to a specific departure event. In the present study, a methodology is developed and validated for reconstructing the most probable departure location of human remains recovered at sea, through the integration of backward Lagrangian drift simulations with large-scale oceanographic and atmospheric datasets provided by the Copernicus Marine Service (CMEMS). The methodology was applied to five bodies recovered in the Aeolian Islands area (Sicily, Italy) between March and June 2024. Simulations were performed using the OpenDrift Leeway model, with an ensemble of several drifters released across five temporal offsets per recovery site. Results were synthesised through a drift probability metric $P_d$ and a newly proposed Hydrodynamic Connectivity Index (HCI), cross-referenced with documented shipwreck incidents and complemented by a wave climate analysis. The methodology successfully identified the port of Bizerte (Tunisia) and the shipwreck event of 5–6 February 2024 as the most probable origin, in full agreement with independent forensic findings, demonstrating the reliability of the proposed approach for forensic reconstruction of shipwreck events in the central Mediterranean and the possibility of being used as aid in recovering further remains. Full article

In the maritime industry, it is common for crew members to be unfamiliar with their workplace until they are on board. This limits evacuation time, which is critical in emergency situations such as fire or shipwreck. The aim of this work is therefore to enhance the preparedness and safety of new crew members by enabling them to become familiar with the location of escape routes before boarding the ship. For this purpose, the use of 360 technology is proposed. A 360 tour is a virtual, interactive experience that allows users to explore a location as if they were physically there. On a ship, this allows the crew to know the escape routes and make quicker and safer decisions on the most appropriate route. This paper shows how a 360 tour was developed and tested on a merchant vessel. The evacuation time from the engine room has been measured for a group of people. The results showed that the 360 tour had a very positive impact on the evacuation time for these people who had not previously been physically present in the area. Full article

To clarify the microbial contamination and wood degradation risk of the Nanhai No. 1 shipwreck hull and verify on-site antibacterial agent effectiveness, microbial samples were collected and analyzed via SEM, metagenomic sequencing, bacterial isolation, enzyme activity detection, and antibacterial experiments. The results showed that Actinomycetota was the dominant phylum, and Brachybacterium, Microbacterium, and Brevibacterium were the dominant genera. Seven bacterial strains were isolated and purified, among which Brevibacterium sp. (NH.SH-B6) had the strongest wood degradation ability, possessing cellulase, LiP, MnP, and Lac activities. When cultured with hull wood as the sole carbon source, LiP was the dominant degrading enzyme of NH.SH-B6, and its maximum enzyme activity was achieved under the optimal conditions of pH = 7, 10% NaCl, 1000 mg/L FeSO₄, and no PEG400 added. 50 mg/mL cinnamaldehyde and 0.5% isothiazolinone K100 had good inhibitory effects on the isolated bacteria, and bacterial proliferation was due to incomplete antibacterial agent spraying. This study clarifies the microbial degradation risk of the Nanhai No. 1 shipwreck hull and provides a scientific basis for optimizing the on-site protection strategy of the shipwreck. Full article

Side-scan sonar is a critical instrument for underwater cultural heritage preservation, as it allows large-scale detection of shipwrecks in turbid waters where optical methods fail. However, the automated segmentation of these targets remains a significant challenge, as severe speckle noise and complex seabed reverberations often obscure the distinctive geometric features of submerged structures. To address this challenge, this paper proposes SW-Net, which utilizes a multi-scale input strategy and a novel Directional Filter Bank to inject physical priors into the feature extraction process. Furthermore, by coupling this with a directional attention mechanism, the network dynamically modulates structural features to accurately segment targets despite intensity inversions and speckle noise. As demonstrated by the experimental results on the AI4Shipwrecks dataset, the SW-Net outperforms seven representative segmentation architectures, achieving the highest intersection over union of 39.43% and an F1-score of 56.56%. In addition, the model exhibits superior robustness against complex seabed interference while maintaining the lowest computational complexity of 4.01 million parameters among the evaluated methods. Taken together, the SW-Net is proposed to offer a practical solution for shipwreck detection on resource-constrained autonomous underwater vehicles. Full article

This study examines three Byzantine-period amphora carriers (Knidos F, L, and N) discovered off the coast of Knidos within the context of Eastern Mediterranean maritime trade. The research is based on deep-water surveys conducted by ROVs from the E/V Nautilus, combined with seabed mapping and typological analysis of amphora assemblages. The Knidos F and L wrecks carried predominantly Günsenin Type I amphorae and date to the 10th–12th centuries, reflecting the revival of Byzantine maritime commerce. Knidos N represents a later, likely 13th-century context with a distinct amphora assemblage. Together, these wrecks highlight the continued commercial significance of the Carian maritime corridor in Byzantine shipping networks. Full article

Side-scan sonar (SSS) imaging plays a critical role in underwater perception for autonomous underwater vehicles (AUVs). However, the spatial sparsity of targets and the limited computational resources remain challenging for real-time object detection. Existing methods typically adopt dense inference strategies, leading to substantial computational redundancy and limited deployment feasibility. In this work, we propose a lightweight and ultra-fast SSS object detection framework based on target presence awareness. The proposed framework follows a coarse-to-fine inference paradigm, in which a target presence analysis module is first employed to rapidly filter out target-absent image patches, and only target-positive patches are forwarded to an Object Forward Detection (OFD) module for fine-grained detection. The TPA module integrates spatial–frequency convolution to efficiently capture both local structural cues and global contextual information with minimal computational overhead. Furthermore, an AttnConv-enhanced detection module is introduced in the OFD stage to strengthen high-frequency target features and improve fine-grained detection performance. Extensive experiments on public SSS datasets demonstrate that the proposed method achieves an mAP of 74.63% on the AI4Shipwrecks dataset and 63.02% on the SSS-Mine dataset. Notably, the framework delivers an ultra-fast inference speed of 174.74 FPS on embedded hardware, representing a 5.2× speedup over conventional dense-processing detection methods. Full article