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England's Protected Wreck Sites

Underwater exploration without getting wet!

There are currently 53 wreck sites in England with statutory designations under the Protection of Wrecks Act, see Figure 1. They are of the highest significance and help define our nation and tell our story. They range from Bronze Age cargo scatters through to twentieth century submarines and include a diverse range of site types in between.

A map showing the location of England's 53 protected Wreck Sites.
England's 53 protected Wreck Sites (November 2017). © Historic England

Responsible access has been a key element of the management approach to the sites championed by Historic England. To support this we have enabled the creation of a number of diver trails on wreck sites designated under the Protection of Wrecks Act (James 2013a and 2013b).

Our experience has shown that by encouraging responsible access sites are better managed and understood. Diver trails provide interpretation material and enhanced access by licensed divers and the increase in the number of visits brings benefits to Historic England. Divers are encouraged to share their photos with us, and this enables site monitoring (for Heritage at Risk purposes), while the additional presence of licensed divers on site can act as a deterrent to anyone thinking of illegally accessing the wrecks.

These dive access schemes have been a success for the economy, for the divers and for Historic England (Beattie-Edwards, 2012). Over 5000 dives have now taken place on Protected Wreck Site dive trails. The Iona II dive trail was recognised at the Association of Heritage Interpretation Awards in 2015 with a commendation in the Interpretation for a Target Audience category, and UNESCO recognises the trails as being examples of best practice for audience engagement.

Increasing access to our maritime heritage

The sport diving community has been instrumental in finding and helping Historic England to manage many of these sites, but not everyone can dive. The very nature of maritime archaeology, lying at the bottom of the seabed in an area only accessible by those with the right training and equipment, has meant that protected wreck sites have only engaged with a very small number of people.

The National Heritage Act of 2002 transferred general functions for maritime archaeology to Historic England (then English Heritage). Since then, there has been a commitment to widening access to protected wreck sites in new and innovative ways. Increasingly we have looked to new technology to achieve this. To enable engagement with non-divers, Historic England is embracing new techniques of display and interpretation; the scheme to provide virtual trails is a good example of this. The trails are showing how technology can be utilised to engage the public with heritage assets irrespective of their ability to physically access the sites. The principle aims of the trails are to provide enhanced interpretation and to inform Historic England’s on-going programme of site investigation and management by encouraging feedback from people using the trails.

Virtual Trails commissioned by Historic England (March 2017)

  • Association (CISMAS)
  • Bartholomew Ledges (CISMAS)
  • Coronation (MAST). Trail completed
  • Holland No 5 (Nautical Archaeology Society)
  • HMS/m A1 (Nautical Archaeology Society). Trail completed
  • HMS Colossus (CISMAS). Trail completed 
  • HMT Arfon (Maritime Archaeology Trust). Trail completed
  • Invincible (Pascoe Archaeology Services). Trail completed
  • London (Cotswold Archaeology)
  • Normans Bay (Nautical Archaeology Society)
  • Tearing Ledge (CISMAS) Thorness Bay (MSDS Marine)
  • Wheel Wreck (CISMAS)
  • U8 German submarine (MSDS Marine). Trail completed

From the outset of the programme we deliberately decided to not be overly prescriptive with the techniques contractors would use. We wanted to stimulate creativity and the application of new technology. We have now taken forward a number of different virtual trails, and all have used slightly different approaches, from standalone websites through to using photogrammetry, virtual reality and computer generated imagery (CGI). In order to ensure that the virtual trails had a consistent feel, it was specified that Historic England branding and style guides should be adhered to in their creation.

A diver exploring a wreck.
A diver exploring the Colossus protected wreck site trail. © CISMAS

The web technology: a case study

The Invincible protected wreck site is the second web tour to be developed through the collaborative efforts of Grant Cox (ArtasMedia) and Stuart Graham (CyanSub) for Historic England, the first being the Coronation, and is a rounded prototype of our ongoing development of a unified HTML5 framework.

Rather than relying on premade tools or code, a key technical ambition in the creation of this technology is to provide an efficient and original framework that unifies all desired content in a streamlined system. Currently this includes the presentation of CGI animation, photogrammetric survey, laserscan data, audio, video, traditional imagery and the possibility for future additions such as Reflectance Transformation Imaging (RTI) panoramas and virtual-reality experiences, all through the web browser. An admin system is also being developed to provide a user-friendly interface for the creation of future tours.

With pure HTML5 delivery, accessibility and the ability to create experiences that can be accessed independently of hardware or administrative rights are key factors in removing as many variables as possible from delivery to the user, such as insufficient graphic cards on mobile devices and restrictive institutional policies.

Along with dynamic web presentation, an ongoing ambition of our collaboration is to bring commercial-level visuals that integrate sophisticated digital processes and CGI techniques. For this, the Invincible virtual trail content creation was comprised of three stages: the underwater data capture by the Invincible dive team (Pascoe Archaeology Services); the formulation of that into a working CGI resource (ArtasMedia); and its translation into our web tour system (CyanSub).

Part of the digtial model for a virtual dive trail.
Example of original data rendered into the model. © Artas Media

Creating the virtual trail

In such varying underwater conditions, the initial data set produced widely ranging outputs and required photography at a very close proximity to the datasets. This caused two problems for its development into a CGI model. Firstly, the majority of sections were fractured into multiple pieces with different colours, visual information and frequently different camera quality (GoPro vs Nikon). Secondly, a side effect of the necessary recording distance was that the RAW photographic information was incredibly detailed. Translating as much of this as possible into the final models required very high-resolution texture sizes and rendering outputs (10k pixels wide in some cases), which made working with the data unwieldy and required a heavy investment in processing and editing time.  

Screenshot showing a high resolution render in the digital model for a virtual dive trail.
The side effect of the team's close proximity diving and the large amount of data. © Artas Media

However, the benefit of this can be seen in the outputs and a short compilation of the working processes required to achieve this can be found in a video presentation. 

Photogrammetry imagery rendered onto a model for a virtual dive trail.
The edited photogrammetry rendered into one large 10k resolution image for the virtual trail. © Artas media

To explain in short, the photogrammetric models (this can also apply to any scan-based data) were taken into three-dimensional re-topology software, reworked into ‘lighter’ meshes, and then the higher density detail was ‘baked’ and reapplied as textural-driven information in the lower complexity geometry. They were then aligned together, connected and heavily edited inside Photoshop to balance colours and fix errors in the recording.

Close up of part of a digital model for a virtual dive trail
The level of detail that was able to be extracted from even very zoomed-in areas. © Artas Media

This process is often used in the CGI pipeline to bring high-quality information into models required in game engines, or just to generally economise scenes. This allowed the combination of multiple meshes into a singular working three-dimensional object and turned very high-density objects into manageable assets.

Screen shots showing the
Pipeline for combining multiple inputs inside three-dimensional software. © Artas Media

Once the above processes were completed, the models, along with other contextual information such as multi-beam surveys, site reports, technical drawings and photographic references, were referenced to build a large section of the underwater site inside the software package 3DS Max, creating an academic resource and reusable model for the team. From this point in the development of the trail, cameras, an adjustable underwater environment, flora/fauna and parts of the wreck not in the survey (such as iron knees and planking) were created alongside the photogrammetry using traditional CGI modelling techniques and rendered into animation sequences and 45 megapixel renders. Finally, all of this was compiled together with the relevant contextual information into the HTML5 framework along with audio and visual narration.

photogrammetry in a virtual dive trail model.
The combination of all re-worked photogrammetry. © Artas Media

Moving forward, the web tour system will not only be refined, but due to its centralised code framework, any future developments can retroactively be applied to existing tour features. This not only provides a financially feasible model to create an original system over successive projects, but also a cumulative return of investment.  

To date, three virtual trails have been delivered and the rest should be live by the end of 2017. These trails are doing exactly what they were designed to do, enthusing new audiences with maritime archaeology and the protected wreck sites. Since the first three trails were delivered, over 5000 people have accessed the sites and taken a virtual tour. The figures are expected to dramatically increase as new trails go live and are promoted. The virtual trails are helping to foster a dynamic heritage cycle ensuring the sites are placed high in the consciousness of the non-diving public and opening up the world of underwater archaeology for all.  

About the authors


Alison James

Alison James

Maritime Archaeologist, Historic England

Alison James has been a maritime archaeologist at Historic England for eight years with responsibility for the protected wreck sites. Previously she worked at Hampshire and Wight Trust for Maritime Archaeology and the Nautical Archaeology Society. She has a BSc and an MA in Archaeology, both from the University of Liverpool.

Grant Cox

Grant Cox

Digital Artist, Artas Media

Grant is a digital artist and archaeologist. After attaining an MSc in Virtual Pasts at Southampton University, he formed Artas Media to develop visualisation techniques and has worked on a number of high-profile sites

Further reading

You can follow these projects on Twitter by using the #HEDiveTrail hashtag.

Beattie-Edward, M 2012 The Local Economic Value of a Protected Wreck

James, A 2013a 'Researching, Protecting and Managing England’s Marine Historic Environment'. ACUA Underwater Archaeology, Proceedings from the 46th Annual Conference on Historical and Underwater Archaeology

James, A 2013b Diving into History with the English Heritage Dive Trails

A screen shot of ta virtual dive trail
Screenshot of the virtual dive trail for HMS Invincible. © Artas Media
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