Photo: one of the Navy's smallest ships, HM Survey Motor Launch Gleaner, passing over the Mary Rose wreck site. Photo: David Prudames. © 24 Hour Museum.
In search of shipwrecks and drowned prehistoric settlements, the Royal Navy has launched the most technologically advanced survey of the Solent seabed yet attempted.
The survey is being conducted in order to assess the impact plans to regenerate Portsmouth Naval Base will have on the archaeology of the historic waters.
Using various surveying techniques the HM Survey Motor Launch Gleaner has been mapping the seabed using a multi-beam echo-sounder and high frequency sonar.
As the vessel's captain, Lieutenant Commander Matt Syrett explained, "We go along and it is effectively like hoovering up the information."
Photo: the technology being used allows instant access to the information being picked up. Photo: David Prudames. © 24 Hour Museum.
As reported by the 24 Hour Museum in June, the Royal Navy's £150-200m redevelopment of the naval base will involve dredging a new approach channel to accommodate the new generation of 50-60,000 ton aircraft carriers.
Senior Archaeological Advisor with the Ministry of Defence, Ian Barnes, explained how the survey is all about finding out what's there and using that information to inform the planning process.
"It's just like building a new road," he said, adding that any significant finds, including any at the Mary Rose wreck site, would have to be taken into consideration and mitigated for.
"If it's inside the designated [Mary Rose] area, it has to go to English Heritage, the same as any Scheduled Monument and with all heritage, the first option is preservation in situ."
While plans for the route of the new channel are yet to be finalised, one of the proposals does impinge, quite seriously, on the Mary Rose historic wreck site. The news prompted the Mary Rose Trust to undertake a series of dives in August, dramatically uncovering a 4.5m section of the bow.
Photo: the new aircraft carriers will be about twice the size of the Royal Navy's current vessels, Invincible and Ark Royal. Photo: David Prudames. © 24 Hour Museum.
However, as the Trust's Jacquie Shaw explained, it is hoped that this new survey will lead to even more important discoveries.
"With all this new technology we are almost re-investigating the wreck site," said Jacquie.
"If the channel compromises the Mary Rose, the surveying we do will give us a better idea of what's down there and will help us to manage the site much better and to understand it further and we can dive probably next year."
Outlining possible objectives for a new dive, Jacquie added, "one of the difficulties this year was the silt and that obviously is an added problem, so there will be some house-keeping, but what we really want to do is excavate around the stern area and probably the bow area. It is very exciting for us to be able to go back to the site."
Image: this diagram shows the position of the Mary Rose wreck site at the centre, with the dive boat Terschelling to its right. Courtesy The Mary Rose Trust.
While the plans to dredge an approach channel 200m wide and around 14m deep are an obvious concern for the Mary Rose Trust, Jacquie was happy that the right procedure is being followed.
"The Navy is very aware of its responsibilities and is behaving very responsibly,"she added.
The Gleaner's crew will be joined on Monday by experts from Wessex Archaeology and detailed surveying is expected to continue until September 12, weather permitting.
An initial desk top assessment has located 174 recorded wrecks and seabed obstructions in the area, although, as the Solent has been a sea route since the Roman era, more discoveries are expected.
It is also possible that hidden artefacts and structures could date even further back to a time when the Solent was dry land.