Fujikura Ltd.

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Mariana Trench Roman

Development of Cable for 10,000 m-class Remotely Operated Vehicle "KAIKO"

Phase.2 Into an Unprecedented Realm

We took on the highly complex development requirements of this project utilizing the Company's world's leading optical fiber technology together with our solid know-how on specialty cable development. Our challenge into an unprecedented area was under way.

Cables for ocean development are as same as underwater cables in that tensile strength is required, but the former differs from the latter in that they are always connected to devices to be used underwater as they move in any direction. Fujikura is a pioneer in underwater cabling. It is proud of its massive number of deliveries, not only of cables, but cable technology for mobile devices, too, like specialty cab tire cables for large-size cranes on land and elevator cables. The Company was thus well qualified to advance into this new, unknown area. Combining our world's leading optical fiber technology with these accumulated cable technologies enabled us to develop the cables for "KAIKO".

The requirements were for the development of the primary and secondary cables for supplying electric power from the mother ship to the launcher and then to the child vehicle to transmit information when using "KAIKO" and support it to submerge to a depth of 10,000 m. At that time, "MAGELLAN 750" of East Port, Inc. (currently: Oceaneering International, Inc.) was capable of traveling deepest underwater and the nominal maximum depth was 7,000 m.

In April 1988, after receiving the order, the Ocean Technology Development Office was newly established in the Coated Wire Operation Division (currently: Metal Cable Operation Division). A full-scale development system was ready, but it started activities with as few as four members. The system consisted of cables (primary and secondary) and accessories (clamps and underwater connectors), and development works for all were carried out in parallel due to the tight development period. The primary cable was as long as 12,000 m and had a mechanical strength of 50 secured tons. The secondary cable was intended to have high flexibility and a weight lower than sea water so as not to affect the kinematic performance of the child vehicle. Both the primary and secondary cables were made using a composite cable structure with a power line core and an optical fiber core. This is where the real challenge started.

Kaiko 7000 Provided by: Japan Agency for Marine-Earth Science and Technology
Kaiko 7000 Provided by: Japan Agency for Marine-Earth Science and Technology

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