| By Thomas B.
Opishinski Sea trials were
successfully carried out during June, 1998 on a trial cruise from Yokamaha, Japan to
Tapei, Taiwan. During the sea trial, the BATHY-2000P performed
exceptionally well, providing continuous, well-resolved, sub-bottom data to depths
exceeding 6000m with greater than 150 meters penetration in some areas.
A data sample is shown at right. This figure details the ability
of the BATHY-2000P to obtain well-resolved sub-bottom data and
the exceptional ability of the system to track the sea floor over rough terrain. |
Sample Data- <click to enlarge>
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| KDD (Japan's Global
Communications) is presently constructing the JIH (Japan Information Highway) cable, a
large-capacity optical-fiber submarine cable that will encircle the Japanese archipelago.
JIH is designed to make Japan a hub of the Asia-Pacific region and further improve the
Japanese telecommunication infrastructure in anticipation of the multimedia age. The JIH cable will encircle Honshu, Shikoku, and
Kyushu islands, and will be landed at some 17 domestic locations including Hokkaido and
Okinawa. The total construction cost of this 10,300-km long cable is slated to be 130,000
million Yen. |
<click for info>
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Employing the world's latest optical wavelength
multiplexing technology with very broadband optical amplifiers, the large-capacity
optical-fiber submarine cable will have a line capacity of 100 Gbps (equivalent to some
1.2 million telephone lines) and will be "self-healing" due to its loop
structure. In other words, the cable system will offer an extremely high degree of
dependability. KDD's subsidiary, Kokusai Cableship Co., Ltd., will use the cable laying
ship, "Pacific Link", to lay the JIH cable. |
cable path &ship- <click to enlarge>
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| During the
cable laying operation it is imperative that the sea floor slope, topography and
geophysical properties are available to the operators aboard the Pacific Link. The
seafloor data provides information to guarantee safe burial of the cable and, more
importantly, aids in protecting the submerged cable-laying tractor from damage or loss.
KDD required a sub-bottom system capable of producing high-resolution sub-bottom data in
the first 3 meters of sediment strata and real-time calculations of sea floor slope for
this project. The BATHY-2000P was selected by KDD because it
provides 8 cm resolution and its ability to track the sea floor over rough terrain. Ocean
Data Equipment Corporation modified a standard BATHY-2000P FM
Chirp Sub-Bottom Profiler in order to provide real-time slope calculations during the
cable laying operation. |
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