Development and Sensing Properties Study of Underwater Assembled Water Depth-Inclination Sensors for a Multi-Component Mooring System, Using a Self-Contained Technique

Abstract

Prototype monitoring techniques play an important role in the safety guarantee of mooring systems in marine engineering. In general, the complexities of harsh ocean environmental conditions bring difficulties to the traditional monitoring methods of application, implementation and maintenance. Large amounts of existing mooring systems still lack valid monitoring strategies. In this paper, an underwater monitoring method which may be used to achieve the mechanical responses of a multi-point catenary mooring system, is present. A novel self-contained assembled water depth-inclination (D-I) sensor is designed and manufactured. Several advanced technologies, such as standalone, low power consumption and synchronism, are considered to satisfy the long-term implementation requirements with low cost during the design process. The design scheme of the water resistance barrel and installation clamp, which satisfies the diver installation, are also provided in the paper. An on-site test has previously been carried out on a production semisubmersible platform in the South China Sea. The prototype data analyses, including the D-I value in the time domain (including the data recorded during the mooring retraction and release process) and spectral characteristics, are presented to reveal the accuracy, feasibility and stability of the sensor in terms of fitting for the prototype monitoring of catenary mooring systems, especially for in-service aging platforms.

Review on Sensors for Sustainable and Safe Maritime Mobility

“…Waves interactions with offshore structures Wave buoy [30] Measuring waves properties X-band radar [31] Monitoring wind turbine support structure (tripod) Fiber Bragg grating sensors [32] Monitoring TLP (tension-leg-platform) of floating offshore wind turbines Inclinometers Bi-axial sensors and top tension meters [33] Ropes monitoring for offshore structures Polymer Fiber Optics [34] Mooring lines monitoring In-line load cells, inclinometers, strain gauges [35] Structural Health Monitoring of Tendons in a Multibody Floating Offshore Wind Turbine Accelerometers [36] Measuring tension of mooring lines of a moored platform in waves Optical sensors [37] Recording the geometry varieties of multi-component mooring lines Water depth inclination sensor [38] Table 3 shows an overall view of notable applications of sensors for waves investigation into offshore structures. Other researchers used different SHM methods for damage detection in offshore structures: a modal strain energy method [39] and the bicoherence function of measured structural acceleration [40].…”