• Dynamic Seabed Mapping

Discover Our Maritime History and Our Amazing Seabed

Launch Date: August 2025

PHASE 1: Summer 2025

10 shipwrecks, 10 Seabed features of special Interest and 5 Sites of Special Scientific Interest to be mapped.

The bathymetric datasets will be uploaded and displayed on the Seabed Viewer.

Details of each shipwreck will be published, and links provided to other databases when available.

Datasets will be regularly uploaded to the Seabed Viewer. This will be patchy at first but will develop over time.

Boats and Equipment

See what we use to find stuff

Operational Updates

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Multibeam Sonar

Multibeam sonar is a technique used to map the seafloor and create detailed 3D bathymetric maps: The sonar sends out multiple sound waves in a fan-shaped pattern, simultaneously, from a transducer array mounted on the ship’s hull. The time it takes for the sound to return to the array after hitting the seafloor is measured to calculate the seafloor depth, or bathymetry.

This technology is widely used in a variety of applications, including underwater geological mapping, shipwreck search and research, and marine environmental monitoring. The hull-mounted sonar transducer/receiver can be operated at speeds of up to 11 knots, enabling rapid coverage of large areas of the seabed. Marathon is equiped with a Norbit WBMS Tx Wide Band Multibeam Sonar, 460 to 700 kHz for ultra-high-resolution images.

Side Scan Sonar

Side Scan Sonar is a sonar technology that plays an integral role in seafloor mapping and subsurface observation. Using the principle of sound reflection, slide scan sonar is able to produce detailed images of the seafloor and objects on the seafloor with a high level of resolution.

Marathon is equipped with a C-Max CM2 EDF sonar with a deck winch and 200m cable.

The main advantage of slide scan sonar lies in its ability to provide a full visualization of the scanned area, allowing researchers, oceanographers and other interested parties to better understand the characteristics of the seafloor and other underwater phenomena. The towfish is usually towed behind the surface vessel at speeds of between 2 and 5 knots.

Marine Magnetometry

Marine Magnetometry Local variations in the Earth’s magnetic field are most often caused by ferromagnetic objects or other magnetic objects located on nor under the sea floor. Through measuring and recording of this variation, it is possible to detect objects submerged beneath the water (and sediments).

An accurate map of the object’s position can be created by recording the sensor’s position along with the magnetic variation. The magnetometer is installed in a water-tight tow fish, which is towed behind the vessel using a tow cable. Marathon is equipped with a Marine Magnetics SeaSpy Explorer magnetometer with an Overhauser sensor.

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