Charting the future, finding the past: MarramWind shipwreck discovery

Beneath the waves

On 2 June 2022, during a routine phase of offshore seabed survey operations, the Fugro Galaxy encountered the unexpected. While mapping the seafloor with side scan sonar (SSS), the crew identified a potential obstruction in its path. To avoid collision, they quickly raised the towed sonar.

High-resolution acoustic imagery soon confirmed the presence of a large wreck structure surrounded by scattered debris. Depth readings from the multibeam echosounder (MBES) showed a vessel approximately 100 metres in length, while sub-bottom profiler (SBP) data revealed layers of disturbance consistent with a major solid object buried in the seabed.

Within hours, the data was assessed and shared with authorities. Given the size and condition of the wreck, it was treated as a potential war grave. Just five days later, a one kilometre exclusion zone was established for its protection, and the process of identifying the vessel began.

The history of SS Tobol

The investigation soon confirmed the wreck's identity: the SS Tobol, a Russian cargo vessel lost during World War I.

Built in 1904 and originally named the Cheltenham, the ship was seized during the Russo-Japanese War by the Russian Imperial Navy while transporting goods to Japan. Its cargo was declared contraband, and the vessel was legally confiscated. In 1905, it was renamed Tobol, likely after the Tobol River in Siberia, and integrated into the Russian fleet.

Twelve years later in 1917, the Tobol was torpedoed by a German submarine while travelling from Blyth, UK to Arkhangelsk, Russia.

Its final location had remained a mystery for over a century until being rediscovered by Fugro's survey.

Discovery through data

The wreck was uncovered as part of extensive marine site characterisation work for MarramWind (Limited), a joint venture between ScottishPower and Shell New Energies UK. The project aims to develop a major floating offshore wind farm located 75 kilometres off the coast of Peterhead, Scotland. Once operational, MarramWind has the potential to deliver up to 3 GW of renewable energy – enough to power around 3.5 million homes.

We were contracted to carry out site characterisation services, including geophysical, geotechnical, and environmental habitat assessments across both the main site and the export cable route. This was one of the largest marine surveys undertaken by our team in the region.

Data acquisition began in 2022, involving several of our dedicated survey vessels. The main site survey alone required navigating over 10,000 kilometres of survey lines across an area of 684 square kilometres.

Comprehensive surveying: How it happens

The discovery of SS Tobol was made possible by the comprehensive and multidisciplinary nature of modern offshore surveying. To build a complete picture of the seafloor and underlying geology, deployed a full range of advanced technologies:

• Mapping the seafloor: MBES creates detailed 3D maps of depth and shape, while SSS provides high-resolution acoustic images of the seabed texture and any objects lying on it. These are crucial for identifying features, obstructions, and even potential hazards like shallow gas visible in the water column data.

• Detecting buried objects: A magnetometer is towed to sense disturbances in the Earth's magnetic field caused by ferrous metal objects buried in the seabed, such as pipelines, unexploded ordnance, or parts of shipwrecks missed by sonar.

• Exploring below the seabed: SBPs and 2D ultra-ultra-high-resolution seismic systems sent sound pulses into the seabed to map the layers of sediment and rock beneath the surface. This reveals subsurface conditions, sediment types, and the location of buried geological features or potential hazards relevant to anchoring and cable laying.

Combining the data from these various sensors provides the detailed understanding needed for the wind farm's design and environmental impact assessment, covering everything from seabed stability and potential geohazards to identifying sensitive habitats and, as in this case, historical artefacts.

A moment of reflection

The MarramWind survey brought together multiple vessels and crews, supported by large onshore teams of geophysicists, data processors, GIS specialists, and environmental experts. Together, they delivered not just the critical Geo-data required for a major renewable energy development, but also located a lost piece of history.

The wreck of SS Tobol is now formally recognised as a war grave, with a permanent 250 metre exclusion zone in place. Ongoing discussions with the UK Hydrographic Office and Historic Environment aim to ensure the site receives lasting protection.

Honouring the past, powering the future

This project highlights what is truly possible when advanced technology, deep expertise, and careful collaboration come together. It serves as a powerful reminder of the value of the work conducted beneath the waves – work that not only supports future sustainable development but also honours and protects our shared maritime past.