Following the short mid-season break, the AURORA is back. We are currently working off the coast of Malta running a side scan sonar survey and have so far completed two days of survey. Overall,the progress has been good.
Today, we are setting up our latest piece of equipment – a Geometrics Magnetometer. A sonar egineer is over from the US and is connecting this tool to the side scan sonar. Once the hook up is complete we will continue the survey with added magnetometer data.
Yes, it has been several days since our last update, but we’ve been busy.
We concluded this season’s efforts in Syracuse and transited the 90-odd miles south to Malta where we are once again at our operating base on Manoel Island across from the great fortified city of Valletta.
The ISIS and FORTALEZA are now side-by-side as we get ready for the next phase of our 2009 season of exploration. The next project is a detailed ROV survey of an area we previously worked at off the Island of Gozo. Additionally, at the end of our 2008 season we confirmed the existence of an ancient shipwreck at the base of a cliff nearby to the Gozo site and we plan to return to further document what appears to be a 5th century BC shipwreck; possibly the oldest discovered in the Maltese Islands.
Additionally, we have added to our capabilities when the project secured access to a Geometrics Magnetometer. This will help distinguish the ancient non-ferrous material from the more modern artifacts. We plan to put this new tool to use off Malta in late August.
AURORA's Founders Craig Mullen & Ian Koblick - A couple Ancient Mariners Looking for Ancient Greek Marimers
Searching in the harbor floor in Syracuse continued through the week without let-up, but also without any breakthroughs. In total, through Wednesday the 29th of July, our team has dove on 20 targets recorded during two years of side scan sonar and sub-bottom profiling in Syracuse Harbor. Between divers probing into and, in some ceases, excavating sizable holes in the thick, sticky mud of the bottom, we have idntified approximately 8 targets as modern artifacts (one was our hoped-for ship hull) and 8 as local geology.
Of the remaining targets 4 were not found at all with several teams of divers probing up to 2 meters into the harbor floor at their recorded positions. Having verified our navigation several times during out time here, we concluded these targets were out of range of our probes.
From our perspective there is a good news – bad news sort of thing in play here. On the positive side, we have confirmed there are targets where our sub-bottom penetrator data predicted. On the negative side, apparently the remains of the several battles fought in the harbor are not represented by large hull sections quickly buried under a couple meters of harbor sediments as speculated, but rather smaller artifacts and possibly buried deeper in the sediments.
We have decided to step back from our field efforts in Syracuse this year and investigate alternative technical approaches for a return in the future. Craig plans to research recent advances in mine hunting technology for new remote sensing options. Our local partners have indicated they will look into obtaining core samples of representative areas of the harbor floor to obtain actual data on local sedimentation.
Lastly, we’re happy to report no Borilla’s were encountered in the murk of the muddy harbor floor. What’s a Borilla you ask?? – Well, it’s a old diver term for something unexpected in the gloom that’s too big for a Bear and too ugly for a Gorilla, but generally flashes by with every potential of returning — hopefully not on your dive!
Our search efforts on the harbor floor continue. Thus far we has been searching for signs of ancient shipwrecks for about 10 days and have thus far, come-up empty handed. Our searching methodology is a combination of technology and tradition. The technology part comes from the use of the Global Positioning System (GPS) to place us precisely over the targets generated by our state of the art sensors. The traditional part comes from the use of SCUBA divers to probe into the mud of the harbor to confirm the presence of ancient artifacts.
“Is it man made or natural?” is the first question, followed quickly by if it’s man made, “is modern or ancient?” Thus far we have identified the remains of a harbor defense screen left over from WWII and an apparently naturally occurring rock formation. We’ve also investigated a number of targets whose burial depth may exceed our ability to hand probe.
Though we use GPS to establish a reference line fastened to the harbor floor (some 23meters below the surface) so the divers have a physical guide, there is no other clue on the bottom that suggests the presence of a buried artifact; the muddy bottom is uniformly flat and featureless where we have concentrated our efforts. To detect the presence of an object of interest, the diver must push a 2 meter long probe into the bottom in hopes of making contact with the target detected by our sub-bottom profiler.
The process is hampered by swirls of fine silt stirred up by the diver’s efforts working on the harbor floor obscuring all visibility and making it difficult to ensure a comprehensive search. The diver often must rise up in the water column to check his gauges and computer. We have reconfirmed our positioning data and feel confident in our ability to identify the targets which lie buried within 2 – 3 meters of sediment (calculated to be the probable depth of deposit since the 415 – 413BC battle took place). Could the estimate of deposition be wrong? This could be tough one for the team!! We’re thinking about some new technology solutions to this problem.
Today we moved the dive support vessel Tuono over a new area from where we can reach 3 more submerged targets. The process has become significantly more efficient than when we started this project last week. within an hour we set the lines over a target, laid baseline and sent the first diver down to explore the seabed. In the mean time, the ISIS set off to mark another target earmarked for exploration. This particular target is buried in two meters of mud. To ensure we were searching in the right place we sent two teams of divers down to prod the seabed with a long steel pole. Both teams confirmed the presence of a solid object deep in the mud. The next team of divers prepared the grid within which we will be excavating a trench measuring 4 X 4 meters by 2 meters deep. We have at least two very hard days of underwater work ahead of us.
On a lighter note, we all lunched on the Tuono today. Captain Alessandro has some fresh fish delivered and we enjoyed this together with some pasta and mussels. It was a great meal with enjoyable company!
Over the past couple of days we have continued diving operations in Syracuse Harbour. There is a preliminary list of 10 targets we are investigating. Initially, the target areas are marked by three buoys – following this, a diver descends to mark the area of study with a baseline and a series of cross-lines. Divers then investigate the muddy seabed with a steel rod. When satisfied by the number of contact points the diver will then mark the area for further investigation. This is done by excavating into the mud using the water dredge and jet.
So far we have investigated three targets but these have turned out to be sterile. Work on the seabed in the harbour is hard and slow due to the low visibility.
On Sunday we went out on the ISIS to survey (with side scan sonar) an area of ineterest off the town of Avola. We identified an interesting target and plan to return there with the ROV.
