On Windows for Deep Submergence Research Vehicle "SHINKAI 6500"

Abstract

"SHINKAI 6500" is the latest manned submergence research vehicle which is characterized by excellent research capability and the deepest submergence capability in the world. Through construction of the submersible, many excellent elemental technologies were established. The technology on viewports made of methacrylate plastic which are adopted as transparent boundary of the pressure hull is estabilshed based on such technologies. The authors have already established design and fabrication technologies on the similar viewports for manned deep submersibles through constructing 2000m deep submergence research vehicle "SHINKAI 2000" which has been constructed in 1981 and is currently in active. In the planning of the viewports for "SHINKA 6500" the authors designed them on the results of "SHINKAI 2000" and performed some experiments by using full-scale specimens to confirm its enough safety to apply to the pressure hull boundary of "SHINKAI 6500". Following conclusions were obtained from the results of the experiments and reliability for practical use has been clarified. (1) It has been found that fracturing pressure of the viewports is about 3500kgf/cm^2 and a safety factor above five is insured to the maximum working pressure 680kgf/cm^2. (2) The viwports have enough endurance ability to the design life of four years. (3) Enough safety is to be insured while the life-support time of 129 hr. (4) Impact strength of the viewports are about 1.8 times as strong as the ones for "SHINKAI 2000" which is already active under water and its validity is successfully confirmed.