The Acoustic System of the Fendouzhe HOV

Due to the strong absorption and attenuation of electromagnetic waves by water, radio communications and global positioning systems are lacking in the deep-sea environment. Therefore, underwater long-distance communications, positioning, detection and other functions depend on acoustic technology. In order to realize the above functions, the acoustic system of the Fendouzhe human occupied vehicle (HOV) is composed of eight kinds of sonars and sensors, which is one of the core systems of manned submersible. Based on the Jiaolong/Shenhai Yongshi HOVs, the acoustic system of the Fendouzhe HOV has been developed. Compared with the previous technology, there are many technical improvements and innovations: 10,000-m underwater acoustic communication, 10,000-m underwater acoustic positioning, multi-beam forward-looking imaging sonar, an integrated navigation system, etc. This study introduces the structure of the acoustic system of the Fendouzhe HOV and the technical improvements compared with the Jiaolong/Shenhai Yongshi HOVs. The results of the acoustic system are illustrated by the 10,000-m sea trails in the Mariana Trench from October to December 2020.

A Deep-sea Sediment Sampling System—Design, Analysis and Experimental Verification

In order to meet the needs of the deep seabed sediment airtight sampling operation of the whole sea depth manned submersible (operating water depth of 11,000 meters). An airtight sampler with the function of holding pressure and coring was designed. Firstly, Using the sediment sampling test platform, taking high sampling rate as the goal and the motion speed of manipulator as the constraint condition, the sediment sampling rate (ratio of the sample actually retrieved by the sampling tube to the insertion depth of the sampling tube) test under different sampling tube inner diameters was carried out, respectively. Then, the pressure drop calculation and analysis of other components such as pressure retaining cylinder and sealing cylinder during the recovery of airtight sampler to the deck are carried out, and the pressure drop compensation during the recovery of airtight sampler is calculated and analyzed based on the pressure compensator. At last, the internal pressure test, high-pressure cabin test and adaptability test between sampler and manipulator are carried out by using the developed prototype of airtight sampler for sediments in the deep sea. The test results verify the feasibility of the design of airtight sampler for sediments in the deep sea, which will provide strong support for the deep seabed sampling operation of manned submersible in the deep sea.