- Underwater test at Ishigaki-jima Island -

January 2013

    "Raicho-S" has a waterproof wired remote control system with a control knob that can be moved through 360 degrees to steer the boat in any direction. This makes it possible for a submerged diver to maneuver the boat backwards or forwards or to turn it to the right or left. To confirm the maneuvering capability of the system, an underwater test was conducted in January 2013 at Ishigaki-jima Island, which is located in southern part of Japan. The length of the wire harness was set at 15 meters for the purpose of the test. Maximum boat speed was set at 1 knot using the LCD touch panel located on the navigation dashboard. The boat stops when the diver releases the control knob. A GPS controlled location system can automatically keep the boat in the position set using the LCD panel.

    Figures 1 to 4 show the "Raicho-S" test conducted at Ishigaki-jima Island. Figures 2 and 3 show the submerged diver maneuvering the "Raicho-S" from a position 4 meters below the sea surface. Figure 4 shows the diver steering the boat while hanging on to the side. Due to the motor driven propulsion system, the boat can be maneuvered more easily when it is moving very slowly than would be the case if it were powered by a conventional combustion engine. As the boat operates virtually silently, sound signal transmission between diver and boat was easily accomplished. Due to the water jet propulsion system, the diver near the boat could access the boat easily and the diver hanging on the side of the boat could maneuver the boat without any danger.

    Based on the results of this test, further development of the wired control system to achieve safer and easier control is scheduled in 2013.

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Fig. 1 "RAICHO-S" cruising offshore from Ishigaki City, Japan's southernmost city. Fig. 2 "RAICHO-S" controlled from underwater
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Fig. 3 Diver and "RAICHO-S" Fig. 4 "RAICHO-S" maneuvered by the diver hanging on to side of the boat

"RAICHO-S" controlled from submerged diver