Press Release
29 March 2012 - Plymouth, England
New High Resolution Multibeam Sonar used on Shipwreck Surveys
This week saw the first use of the new ultra-high resolution 700 kHz Sonic 2024 multibeam sonar from R2Sonic. The new sonar was used to map a number of shipwrecks on the seabed near Plymouth, England, as part of on-going historical research by ProMare for the SHIPS Project. Aiming to achieve high quality images the survey was done using the very latest features from the Sonic 2024 multibeam sonar interfaced with an iXBlue HYDRINS Inertial Navigation System and Trimble RTK GPS receiver. The sonar head was mounted on a purpose built deployment pole fitted to the survey vessel Seeker which is based in Plymouth.
The first site to be mapped was the U.S. Liberty ship S.S. James Eagan Layne beached in 25m water in Whitsand Bay in March 1945. The site was first mapped using 400 kHz sonar with 0.5° beams, including using the Swathe Sector Rotation (SSR) capability of the R2Sonic sonar to clearly image the thin, upright sides of the vessel. The sonar was then switched to using the new ultra-high resolution 700 kHz with 0.3° beams producing even finer detail over the same areas. A very detailed plan of the wreck site will be created from the results of this survey and will be used to help monitor the degradation of the wreck. Making a plan should now be a simple task as the remains of the engine, boilers, decks, deck beams and even the cargo could clearly be identified.
The remains of the Free French minesweeper Poulmic lost in 1940 were also mapped using the R2Sonic sonar as part of an on-going study of the wreck. The site was first mapped using the standard 400kHz frequency, and again this was followed up with higher resolution 700 kHz. The real time images from the sonar identified hull frames and other structure on the seabed even amongst deep rock gullies. The data from this survey will be used to improve the plan of the site and to help identify other parts of this very scattered wreck that have not yet been discovered.
Other wreck sites mapped include the frigate HMS Scylla scuttled in Whitsand Bay in 2004, Hopper Barge #42, HMT Elk and the remains of and the steam yacht Glen Strathallan sunk as an artificial reef in 1970.
The work was done as a collaboration between a number of groups and organisations. The multibeam system was provided by Jesper Høejdal at R2Sonic LLC and James Williams at Swathe Services in Saltash. The HYDRINS was provided by iXBlue, 3H Consulting Ltd. provided survey planning, students from the Plymouth University MSc IHO CAT A Hydrography course provided manpower, GPS and post processing support while Steve Wright provided the survey vessel Seeker.
Links
R2Sonic LLC
Swathe Services
iXBlue
3H Consulting Ltd.
Plymouth University MSc IHO CAT A Hydrography course
Survey vessel Seeker
Join the SHIPS Project on facebook: www.facebook.com/TheShipsProject
The SHIPS Project is a organised by ProMare UK and 3H Consulting Ltd.
Contact: Peter Holt, Project Manager, SHIPS Project
Email: pete@3HConsulting.com
Web: www.promare.co.uk/ships