The submersibles, Nemo and Nomad aboard the Baseline Explorer, have been outfitted with high-tech gear for our collaboration with the National Ocean Atmospheric Administration (NOAA), just one component of the diving assets being used for a mission off the coast of North Carolina. The technology is similar to what would be installed on a space vehicle for a mission to explore another planet. But, our destination isn’t some far away world, instead we are going down ~700 feet below the surface of our own planet to visit two World War II shipwrecks from the Battle of the Atlantic. The mission is to document and recreate the shipwrecks that haven’t been seen by humans since they sunk, a distant 74 years ago.
In order to be able to recreate the battle field the submersibles needed some new technology that would make it all possible.
“Satellite navigation doesn’t penetrate subsea so we need to do a lot of other tricks to navigate underwater,” said Mikael Larsen from Sonardyne International a company from the UK that specializes in subsea navigation. “The type of navigation that we have brought on board is called inertial navigation. It’s the same type of navigations that’s used to navigate nuclear submarines, intercontinental aircraft, ICBMs, and space vehicles. It’s a technology that came out of the space race and the Cold War era that was then adopted by the commercial off shore oil and gas industry and has since then been applied to oceanography and now subsea archeology.”
An inertial navigation system (INS) uses a computer, motion sensors, and rotation sensors to calculate the position, orientation, direction, and speed of an object, in this case the submersible’s location in relation to the wrecks which will enable 3D modeling capabilities
“We are outfitting one of the subs with a laser scanner, that can measure the seabed relative to the sub in a line and by traveling across an area then we map the subsea profile as we go along," said Larson. "Now In order to create a 3D model of that we need to know how the sub is oriented and exactly where it is to mill metric accuracy. And so the laser will do the mapping of the seabed and the inertial navigation will take those points and gear-reference them so we end up with a 3D model of what we map, so in this case a World War II submarine.”
Sonardyne Compatt Transponders were deployed surrounding the wreck site before sub diving could begin. An transceiver aboard the submersible acoustically measures distance to the Compatts. Through combination of the ranges with a state-of-the-art Doppler Inertial navigation system, the sub determines its position in relation to the wreck to mm accuracy in support of the laser profiler. The Compatts were deployed on the 22nd and 23rd of August from the Baseline Explorer, so that submersible diving could start on the 24th of August.
Project Baseline and its sponsor GlobalSubDive
are providing diving assets to NOAA to visit the remains of several other shipwrecks 30 miles off the shore of North Carolina. While diving Project Baseline will be setting up its own observation stations, taking samples, and helping archaeologists document the deep sea wrecks. The first two wrecks being visited include a German U576 and Bluefields. Global Underwater Explorer
technical divers will not be deployed until August 29th (subject to change) to explore wrecks at depths up to ~400 feet. The submersible and scuba diving operations are being carried out from August 22nd to September 6th.
Submitted by Amanda White
Image credits: UNC Coastal Studies Institute and Amanda White/Project Baseline