In view of these requirements, the "Mirai" has been designed with a high freeboard to minimize the probability of seawater rolling in. It also has synchronized hull rolling, achieved by setting the center of gravity to keep the natural frequency of rolling between 14 and 17 seconds. The rolling angle is substantially reduced by the use of a newly developed hybrid anti-rolling system, Heaving motion, caused by pitching, of observation equipment suspended from a stern A-frame crane is absorbed by an active swell compensator. These preventive measures have enabled successful handling of a large water sampler in sea conditions of more than 5m in significant wave height, a condition that was previously too rough for use of this type of equipment.
A second characteristic of the "Mirai" is its ability to quickly deploy and recover many large observation buoys. The vessel has stared deployment of newly developed Triton buoys mainly in the equatorial part of the West Pacific, a vital area for the elucidation of the El Nino phenomenon. It is also equipped with the world's biggest doppler rainfall radar on a research vessel, This is used for investigation of the mechanism of tropical rainfall.
A third notable feature of the "Mirai" is its on-board sample analysis and data processing capabilities. Its on-board laboratories and analytical instruments are used for higly accurate analysis of samples. It is further provided with an optoelectronic LAN and a CATV-based on-board data management system, both among the largest for a research vessel. These are used to integrate, on a real-time basis, data from many observation instruments and analytical apparatuses. This data is organized into databases for use in various further analyses. Every laboratory on board can exchange Internet mail with research institutes and other research vessels all over the world via INMARSAT and other satellite communication means.
To effectively accomplish these observational missions, the "Mirai" is equipped with a diesel-electric hybrid propulsion system with two highly skewed controllable pitch propellers and two bow thrusters, plus one stern thruster, which together facilitate maneuvering with a joystick. To suppress noise radiation into the water, the main propulsion engines and main generator engines are supported by a horizontal two-stage vibration damping system. The vessel's electronic navigation system is a differential GPS, and its acoustic navigation system, an SSBL.
Scientists all over the world are invited to propose subjects for study using the "Mirai" as a research vessel open to both Japanese and foreign initiatives. The "Mirai" is scheduled to embark on a regular research voyage in the fall of 1998.
Japan Marine Science and Technology Center
Address： 2-15, Natsushima-cho, Yokosuka 237-0061 Tel： +81-468-66-3811 Fax： +81-468-66-2119
