Field experiments and new design of a spilled oil tracking autonomous buoy

Abstract

It is important to forecast the location of oil spills to realize effective and adequate oil spill response operations when huge oil spilsl occur. In order to enhance the accuracy of oil drifting simulations, one needs to obtain the meteorological and oceanographic data around the oil slick. In general, the drifting velocity vector of an oil spill contains a wind velocity vector and a water current velocity vector. SOTAB-II was developed for autonomous tracking of oil slicks drifting on the sea surface. It is equipped with a sail whose size and direction are controllable to drift along with the oil slick autonomously. In addition, SOTAB-II transmits its location and necessary measured data around it to the land base in real-time. The results of field experiments using SOTAB-II with a cylindrical hull brought us the effectiveness of the sail and its control. However, the drifting speed of SOTAB-II was lower than a theoretical speed for the oil slick. In order to overcome this problem, SOTAB-II was redesigned. A yacht shape was adopted to reduce the hydrodynamic drag in the water in the advancing direction. Transverse stability, scales of brake board and sail, maneuverability, and performance of tracking spilled oil on the sea surface were considered in the process of the design.

A Survey on Unmanned Surface Vehicles for Disaster Robotics: Main Challenges and Directions

“…While the SOTAB-I collects rough data on physical and chemical characteristics of plumes, consisting of spilled out oil and gas, SOTAB-II USVs track the spilled oil on the sea surface. Also using SOTAB-I and SOTAB-II, Senga et al [111,112] perform experiments in Biwa Lake and Osaka Bay, Japan, to verify the effectiveness of sail and sail control for tracking oil plumes. Experiments indicate that once the buoy is dropped into the oil slick drifting on the sea surface, it sets out to drift with the oil slick using the wind force by effectively controlling the sail size and direction.…”

Autonomous Spilled Oil and Gas Tracking Buoy System and Application to Marine Disaster Prevention System: Part 1

“…From the analysis of field experiments using the basic type of SOTAB-II, it was concluded that the sail control system of SO-TAB-II works well, but SOTAB-II with a cylindrical hull can't reach the target drifting speed [12]. As for the drifting function, SOTAB-II installed with a bigger sail may meet the required drifting speed.…”

“…If the drag force on SOTAB-II is so big, the auxiliary propulsion mechanism uses large electricity to bring SOTAB-II a certain location. Therefore, we design a new model of SOTAB-II with a yacht shape to reduce the drag coefficient in water [12].…”

Development of a Mobile Buoy with Controllable Wings: Design, Dynamics Analysis and Experiments

“…However, the SOTAB-I is still not suitable for long-distance travel due to the use of propellers. To improve long-distance travel, the SOTAB-II [10] uses a sail and oscillating fins to control the buoy motion. Due to the use of sails and oscillating fins, the mechanics of SOTAB-II is more complex than other traditional buoys.…”