Shipwreck Hunting Around Malta
Timmy Gambin, Associate Professor of Maritime Archaeology, University of Malta and his team utilize modern Gavia AUV technology to help uncover the mysteries of ships lost at sea.
By Greg Trauthwein
Timmy Gambin, Associate Professor of Maritime Archaeology at the Department of Classics and Archaeology, University of Malta, coordinates the university’s Masters in Maritime Archeology, program, a program with seven students from different corners of the world. Professor Gambin also directs field work as part of the Maritime Archeology program. “And one of the biggest parts of our field work is going out with our AUV to survey the seabed,” he said.
Given its juxtaposition to the beginnings of shipping, the waters around Malta are teeming with discovered and yet-to-be-discovered historic shipwrecks and artifacts. Professor Gambin and his team are the tip of the spear to survey all of Malta's territorial waters “which measure about 3,500 square kilometers, but minus a bit because we only survey from the 50-meter contour down to whatever depth are present in our territorial waters, which is about 1,100 meters,” he said. “We believe most of the archeology shipwrecks and aircraft that are situated shallower than 50 meters have mostly been found by scuba divers, or they are covered by sea grass and sediment.”
In 2018 Professor Gambin’s team procured a Teledyne Gavia Autonomous Underwater Vehicle (AUV) which is good to 500 meters, and today it is looking to secure funding to get it rated to 1,000 meters, helping his team to cover most of the seabed in its territorial waters.
“The topography is pretty conducive to survey,” said Professor Gambin, noting that it is mostly defined by gentle slopes, with a few sea mounts. “We started with a towed system and now have moved on to this AUV for the past three years. We still have a lot to go down to the 500 meter contour, but the results so far have been pretty spectacular.”
Expanding the “Toolbox”
Since 2018 the Gavia AUV has been the literal ‘pack mule’ tool for searching the waters around Malta, with payloads including a dual-frequency side-scan sonar – 600 kHz for the main survey work and 1,600 kHz for the higher resolution work. “The Gavia software is ideal for us because it's very easy to train our students. It's very easy to utilize. It's also very easy to switch parameters once the AUV is up in order to get higher resolution sonar imagery,” said Professor Gambin.
In 2018 when the decision was taken to acquire an AUV, Professor Gambin and his team were using a towed system which had its limitation. “We still have our towed system which has 500 meters of armored cable. But realistically you need a specific boat that can take that winch with all the weight. You can only work probably down to 200, 230 meters with that amount of cable out.”
While the AUV comes with a higher CapEx, it offers a number of strategic efficiencies, namely efficient use of something you cannot buy nor replace: time. “Working with an AUV cuts your work time by a significant percentage because you don't need to recover the cable. So that is what pushed us towards an autonomous system,” said Professor Gambin, noting that after the public tender, the Gavia AUV “ticked all of the boxes” in regards to simplicity of use, modularity and flexibility. “For example, we can reduce the size of the AUV and deploy it from a RIB, or we can deploy it with all the tools that makes it slightly larger, but still deployable from a normal boat.”
“The other thing about using side-scan with an AUV is the complete clarity of the data. When you use a side-scan with a towed system, the vibration of the cable is translated into your dataset, but with the AUV it's smooth, with crisply clear and high-resolution data.”
To give you an example, one of the major projects we're working on now is we partnered with the Italian Superintendents of the sea and the RPM Nautical and we're using the AUV to survey the area of the Battle of Aegates, a naval battle fought in 240 BC between the Romans and Carthaginians,” said Professor Gambin. “We're actually looking for things as small as swords and bronze rams, and we're picking them up. I've been using side-scan for over two decades and I was pleasantly surprised with the amount of discoveries that we're churning out of the Egadi Islands.”
The Gavia AUV
“The Gavia AUV that the University of Malta procured is a 500-meter depth rated system, a fully modular autonomous underwater vehicle, which means that you can reconfigure it on the back of the ship or in the lab prior to deployment and you can do battery swapping and actually have longer duration missions and get the data at the meantime as well,” said Stefán Reynisson, General Manager, Teledyne Gavia. “It has an inertial navigation system, an iXblue C3 coupled with a Teledyne RDI workhorse DVL for subsea navigation. That subsea navigation is also enhanced with a Directional Acoustic Transponder or DAT which is mini USBL system made by one of our Teledyne sister-companies Teledyne Benthos. We use the Teledyne Benthos acoustic equipment as well for communication with its subsea. Then for the sensor package, they have EdgeTech 2205 pool frequency side-scan sonar. The lower frequency at 600 kHz and a higher frequency at 1,600 kHz. They also have a MB2250, which is a BlueView Multibeam at very high resolution at 2.25 Gigahertz that can be used for micro-bathymetry and extremely high-resolution multi-beam detection.
This client for Gavia was unique in a sense, as its AUVs are generally bought and deployed for commercial survey. “They're our first client with a focus of underwater archeology and wreck finding,” said Reynisson. The big win from the Gavia side was the utilization of its commercially made sensor suite, a suite that “fits so well within the mission profile of the University of Malta as well as the ease of use that they've had with the ever-changing students coming in and out into their program,” said Reynisson.
Seek and Find
To date Professor Gambin and his team have recorded hundreds of historically significant finds with its Gavia AUV, and he laments that picking a favorite is analogous to “picking your favorite son, which is impossible.” But there is one that stand out.
The submarine HMS Urge was lost in 1942, and a search was commissioned to the TheUniversity of Maltaby the submarine commander’s grandson.
“She (HMS Urge) left Malta on her way to Alexandria (but) never turned up and nobody knew where she was lost,” said Professor Gambin. The search for this submarine was important for the family, as it was claimed to have been found off Libya which would have brought dishonor on the commander and his crew (for apparently disobeying orders). The University of Malta team found the submarine, and importantly brought together the historical, the technical and the human elements. “This was very important from a human level,” said professor Gambin, noting that a commemoration ceremony is planned for April 2022, the 80th anniversary of its loss, with about 80 family members expected to travel to Malta for the event.