(3) Propulsion motor: 1500kW, 6P, 1150V, 2 sets
(4) Propeller: fixed pitch. 360° azimuth type, 2-stage gear reduction, with nozzle
The propulsion-related electric equipment is manufactured by Nishishiba Electric Co.,Ltd.
13.2 Electric Equipment of Deep-sea Survey Ship
The deep drilling ship forming the core of the "deep-sea drilling technology development" (OD21 Project) promoted under the leadership of the Science and Technology Agency and the Japan Marine Science and Technology Center will be completed in 2003, and its basic design and construction was started since 1999 FY as the deep-sea survey ship over the waters of 2500m in depth.
A large number of electric equipment including the on-board drilling system, and the sub-sea system will be installed on board the ship, and the design of the electric and electronic equipment related to the dynamic positioning system (DPS) will be described here.
The main propulsion system is of electric propulsion type comprising 6 sets of azimuth thrusters and 1 set of bow tunnel thruster, and the azimuth thrusters have the function for both the navigation and the dynamic positioning system (DPS). The dynamic positioning system is a device to maintain the position of the ship at the target point during the off-shore drilling work, and comprises the sensor system to measure the position of the ship, the azimuth, the rolling, the wind direction and the wind speed, the control system to process the information from the sensor system and gives the control signal, the propeller to generate the force resistant against the external force such as the wind, wave, the tidal current, etc. based on the signal from the control system, and the generating plant to supply the electric power to the propulsion system.
The NK notation of B class will be acquired for the dynamic positioning system of the ship, and its system constitution is redundant enough to satisfy the requirements.
References
1) Bulletin of The Society of Naval Architects of Japan, 849 2000/3, offshore of 21st century; a special issue
[Yukiteru NAGUCHI]
14. Ocean Engineering Machinery and Offshore Structures
14.1 Offshore Oil Field Structures
The drilling semi-submersible rig was built in Ariake Shipyard of Hitachi Zosen. The double and triple safety and environment maintenance countermeasures are provided since the rig achieves the drilling operation under the very violent meteorological and sea conditions in North Sea. The rig is also equipped with the dynamic positioning system, and furnished with the computer-controlled automatic pipe handling system and the mud water processing system to realize the labor saving in the dangerous works. In addition, two sets of "ram ring" to drive the drilling pipe by the hydraulic system in place of the conventional wire work are equipped for the first time in the world to realize the comprehensive efficiency in the works including the simultaneous drilling of two oil wells. The rig is the first of the "Fifth Generation Oil Drilling Semi-Submersible Rig", which is remarkably different from the conventional oil drilling rig in the performance aspect.
14.2 Ocean Organic Resources Development
Kawasaki Heavy Industry built three sets of large steel floating gathering-place for fish intended for Okinawa Prefecture. These facilities aim at forming the gathering-places for fish in which marine organisms adhere and grows on ropes with branched lines stretched over the man-made sea bed to allow large migratory fish (tuna, bonito) to gather and stay, and have frame structural bodies forming the regular hexagonal man-made sea bed of 8m in one side length below surface layer buoyant bodies, which is single-point catenary moored at the water depth of 1000 to 1500m. This system has been very popular recently as the "PAYAO" fishing method devised by fishermen in Okinawa.
14.3 Ocean Space Utilization
The second term research on the super-large floating marine structure (Mega Float) has been implemented on the three-year program since 1998. One of the objectives of this research is to confirm by the demonstrative test whether or not the floating structure has the function requested when it is used as an airport. In August, 1999, a demonstrative floating model (the largest floating structure) of 1000m in length, 121m/60m in breadth, and 3m in depth appeared off Yokosuka, and was disclosed to the public on the execution in the afloat condition. In addition, on the Disaster Prevention Day of September 1, an emergency drill was carried out using the floating structure, demonstrating the function as the disaster prevention base which is one of the mode of utilization of the floating structure.
