Underwater Survey Diving

The current research focuses on the question of thematic diving tourism, in the light of the Greek project on the first group of 91 historical wrecks of ships and aircrafts which have become open to divers.

In order to perform a preliminary investigation on the available data on the internet for the listed 91 wrecks at the Joint Ministerial Decision (No. 92225 of 3 March 2022), of the ministers of National Defense, Culture and Sports as well as Shipping and Insular Policy, a data table was prepared providing some available web links from various resources. This work is expected to facilitate the documentation of the 91 wrecks and furthermore to provide a methodology to be applied towards the characterization of other historic wreck in the Greek seas.

The BRITANNIC, generally known as the sister boat of the TITANIC, was built as an ocean liner, but she was refitted as a hospital ship during World War I and sank in November 1916, reportedly after striking a mine. In virtue of law No. 3409 of 2005, scuba diving for recreational purposes has been liberalized in the Hellenic legal order. In Greece, the time which is required in practice for issuing a permit for the underwater remark of a wreck, as it is the case of the BRITANNIC, is quite big and may reach the time of 8 months. A joint ministerial decision was issued in March 2022, in the matter of 91 underwater wrecks, including the BRITANNIC and the comparable case of BURDIGALA. A documentation process is required for each of those monuments and then the visit will be permitted on certain conditions, such as notification of the visit at least one day in advance. So, a lot of wrecks are expected to become visitable but interesting cases of shipwrecks are excluded. Last but not least, Greece should acquire an archaeological contiguous zone, which would be beneficial inter alia for the French shipwreck “FLORÉAL”.

The information here presented thus represents far more than just an assemblage of data; it is a collection of evidence which reinforces much larger historical, political, cultural and environmental narratives that are in some cases still ongoing. As a preliminary report, this paper invites further inquiry: both into the wrecks, and into their relationships with the contexts in which they are framed.

This study aims at the protection of sunken ships from the Great War or their remainings in the Greek seas as material assets, but also at the preservation of the intangible cultural heritage, associated with the related wreck sites. This is achieved by the cartographic documentation of those wreck sites and the definition of a preliminary set of criteria, for the evaluation of their vulnerability. In our study we have used the example of the shipwrecks from the first World War (WW I) in the Greek territory as this era was characterized by major changes in shipbuilding and has affected the modern history of Balkan region. Through this research: a list of wrecks was created, in order to present what is found underwater, a map was designed to identify where those wreck sites are located and a prioritization list was derived towards the protection of wrecks (as material) and the preservation of their history and significance for the society (as intangible cultural assets). The results of this study are expected to be used as a basic reference for further multidisciplinary research on the documentation, the protection and the promotion of underwater cultural heritage.

This study aims at the protection of sunken ships from the Great War or their remainings in the Greek seas as material assets, but also at the preservation of the intangible cultural heritage, associated with the related wreck sites. This is achieved by the cartographic documentation of those wreck sites and the definition of a preliminary set of criteria, for the evaluation of their vulnerability. In our study we have used the example of the shipwrecks from the first World War (WW I) in the Greek territory as this era was characterized by major changes in shipbuilding and has affected the modern history of Balkan region. Through this research: a list of wrecks was created, in order to present what is found underwater, a map was designed to identify where those wreck sites are located and a prioritization list was derived towards the protection of wrecks (as material) and the preservation of their history and significance for the society (as intangible cultural assets). The results of this study are expected to be used as a basic reference for further multidisciplinary research on the documentation, the protection and the promotion of underwater cultural heritage.

This paper examines the results of image enhancement and point cloud filtering on the visual and geometric quality of 3D models for the representation of underwater features. Specifically it evaluates the combination of effects from the manual editing of images’ radiometry (captured at shallow depths) and the selection of parameters for point cloud definition and mesh building (processed in 3D modeling software). Such datasets, are usually collected by divers, handled by scientists and used for geovisualization purposes. In the presented study, have been created 3D models from three sets of images (seafloor, part of a wreck and a small boat's wreck) captured at three different depths (3.5m, 10m and 14m respectively). Four models have been created from the first dataset (seafloor) in order to evaluate the results from the application of image enhancement techniques and point cloud filtering. The main process for this preliminary study included a) the definition of parameters for the point cloud filtering and the creation of a reference model, b) the radiometric editing of images, followed by the creation of three improved models and c) the assessment of results by comparing the visual and the geometric quality of improved models versus the reference one. Finally, the selected technique is tested on two other data sets in order to examine its appropriateness for different depths (at 10m and 14m) and different objects (part of a wreck and a small boat's wreck) in the context of an ongoing research in the Laboratory of Photogrammetry and Remote Sensing.

This paper attempts to locate the sites of shipwrecks that were caused during World War II (WWII). The research focuses on Pagasitikos-Pelion area (Magnesia) and is based on the georeference of descriptive data from various sources through place-names. The on-map located shipwreck sites combined with the basic characteristics of vessels and details for their wreckage are composing the geographic features which are used for the thematic mapping of a hidden aspect of our maritime history. The results from this preliminary study are intended to be used as reference material for further documentation, protection and promotion of the underwater cultural assets that are related to WWII.

Facing the lack of an established dive training path for the scientists of the marine sector, a new course has been developed for the training on the applied methods and procedures for underwater surveying. This is considered an initial step, both in terms of training and research work, as data capturing is the base of most scientific projects underwater. This paper presents the training program, entitled "Introduction to Applied Methods and Procedures for Underwater Surveying", which has been recently proposed to be offered as a Lifelong Learning Course by Aristotle University of Thessaloniki.

This table displays selected properties of the ships wrecked during the 2nd World War at the Greek Seas. The table includes seven sheets, one for each year, from 1939 to 1945. Each sheet has the following fields: ΟΝΟΜΑΣΙΑ (Name), ΣΕΛ. (ΝσΕΘ) ( Page), ΣΗΜΑΙΑ (Flag), ΤΥΠΟΣ ΠΛΟΙΟΥ (Type), ΠΡΟΩΘΗΣΗ (Propulsion), ΧΩΡΗΤΙΚΟΤΗΤΑ (Volume), ΕΤΟΣ ΝΑΥΠΗΓΗΣΗΣ (Build Year), ΗΜΕΡΟΜΗΝΙΑ ΝΑΥΑΓΗΣΗΣ (Wreckage Date), ΑΙΤΙΑ ΝΑΥΑΓΗΣΗΣ (Wreckage Cause), ΗΜΕΡΟΜΗΝΙΑ ΑΝΕΛΚΥΣΗΣ (Recovery Date). One additional field (WS_name), shows the ship name as it is displayed at www.wrecksite.eu.

This study investigates the potential exploitation of modern wreck sites at the area of southern Pelion and northern Evia. The idea behind this investigation is that each site is characterized by a set of properties which could be used as customized criteria for planning and performing thematic underwater tours. The present effort is part of an ongoing project for surveying and studying the wrecks history, with the voluntary engagement of divers or non-divers.

This study investigates the potential exploitation of modern wreck sites at the area of southern Pelion and northern Evia. The idea behind this investigation is that each site is characterized by a set of properties which could be used as customized criteria for planning and performing thematic underwater tours. The main objectives of this paper are: a) the cartographic representation of the wreck sites at the study area; b) the attribution of wrecks with site specific properties; c) the categorization of wrecks based on their properties; and d) the proposition of thematic tours at wreck sites with contextual properties. The results of this process are expected to be used as documentation material, initially by the scuba community (for recreational and training purposes) and subsequently by researchers. The present effort is part of an ongoing project for surveying and studying the wreck's history, with the voluntary engagement of divers or non-divers. The anticipated outcome from this project is the responsible participation of the public in the protection of cultural heritage at the Greek seas.

The purpose of the Underwater Survey Diver - Student's Manual is to provide the basic knowledge and the skills for those divers and researchers with a special interest in natural and cultural features of the marine environment, so they can be able to participate in the preparation and the carrying out an underwater survey campaign.

This paper examines the results of image enhancement and point cloud filtering on the visual and geometric quality of 3D models for the representation of underwater features. Specifically it evaluates the combination of effects from the manual editing of images’ radiometry (captured at shallow depths) and the selection of parameters for point cloud definition and mesh building (processed in 3D modeling software). Such datasets, are usually collected by divers, handled by scientists and used for geovisualization purposes. In the presented study, have been created 3D models from three sets of images (seafloor, part of a wreck and a small boat's wreck) captured at three different depths (3.5m, 10m and 14m respectively). Four models have been created from the first dataset (seafloor) in order to evaluate the results from the application of image enhancement techniques and point cloud filtering. The main process for this preliminary study included a) the definition of parameters for the point cloud filtering and the creation of a reference model, b) the radiometric editing of images, followed by the creation of three improved models and c) the assessment of results by comparing the visual and the geometric quality of improved models versus the reference one. Finally, the selected technique is tested on two other data sets in order to examine its appropriateness for different depths (at 10m and 14m) and different objects (part of a wreck and a small boat's wreck) in the context of an ongoing research in the Laboratory of Photogrammetry and Remote Sensing.

The purpose of this paper is to outline a course for the training of divers with a special interest in underwater surveying (e.g. surveyors, archaeologists, biologists, geologists, photographers/videographers). This outline presents: i) the Courses' Standards ii) the Learning Objectives for the related Knowledge Development, iii) the Skills that have to be conducted, iv) the Performance Requirements for the students and v) the Open Water Considerations for the Training Dives. It is expected that the resulting course outline will be used as a reference for the training of certified divers who want to become underwater surveyors, providing them basic knowledge and skills to survey adequate data for the detailed documentation of submerged features. Moreover the combination of knowledge (what) and the skills (how) that are presented during the proposed course attempt to define a protocol for the recording of underwater features in favor of mapping and 3D modeling.

This paper presents the results from an underwater recording of the stern part of a contemporary cargo-ship wreck. The aim of this survey was to create 3D representations of this wreck mainly for recreational diving purposes. The key points of this paper are: a) the implementation of the underwater recording at a diving site; b) the reconstruction of a 3d model from data that have been captured by recreational divers; and c) the development of a set of products to be used by the general public for the ex situ presentation or for the in situ navigation. The idea behind this project is to define a simple and low cost procedure for the surveying, modeling and 3D representation of a diving site. The perspective of our team is to repeat the proposed methodology for the documentation and the promotion of other diving sites with cultural features, as well as to train recreational divers in underwater surveying procedures towards public awareness and community engagement in the maritime heritage.

In the field of underwater survey, there is a variety of methods which differ from each other in terms of the operating environment and the purpose that each method is used. Hence, some of the state-of-the-art methods, that have many applications in the various scientific fields nowadays, are introduced in this paper. Additionally, the application of the procedures for an underwater survey in shallow depths is analyzed in accordance with the training standards of the PADI Underwater Survey Diver distinctive specialty. The main goal is to demonstrate not only the theoretical background of underwater surveys but also their operational issues, in order to facilitate the development of knowledge and skills during a training course. Finally, a case study for the recording and 3D modeling of the seabeds' morphology in shallow water is presented as it has been organized and accomplished by the participants of such a training course. By this way, it is expected that the reader will understand explicitly the application of the procedures prior, during and after the dive for an underwater survey in shallow depths.

This is a draft version of the student's manual, which provides the outlines for the PADI Underwater Survey Diver training course. The purpose of this book is to introduce the basic knowledge and the skills for those divers or researchers with a special interest in natural and cultural features of the marine environment. It is expected that by the completion of the specific course divers will be able to participate in the preparation and the carrying out an underwater survey campaign.