July, 2009

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Sunday, July 26th, 2009

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.