Design, construction and testing of a semi-autonomous surface drifting buoy for coastal observations
An area in float design that has gained interest is the ability to transport large payloads in an efficient and persistent manner, on the orders of one ton over a period of many months. Traditional thrusters are unable to perform this mission for a long duration because of their high continuous energy usage. Additionally, the large scientific measurement payloads are traditionally repositioned using a ship. The project's proposed solution is to design, build and test a variable buoyancy system integrated onto a float whose purpose is to use the oceans currents as its main transport mechanism. ^ The buoyancy system was based on a closed pump-bladder configuration, where hydraulic fluid is pumped from a flexible bladder to rigid pressure tanks to control its buoyancy. After design and construction, initial bench testing was conducted, followed by tank testing in the OCE Acoustics tank and a final bay test in the west passage of Narragansett Bay. Performance characteristics of the float were found to draw an average of 4.6W over a 12 hour submergence-surfacing cycle and was able to change its buoyancy by 25 lbs over a 15 minute period. The float was also able to travel approximately 5 nautical miles during the bay test over one ebb tidal cycle. The tank and bay test were successful in proving the concept of the design, though additional work is needed to for the float to overcome its current problems and failures as well as to achieve its longer term goals of obstacle avoidance, persistent operation, and global communications.^
Engineering, Marine and Ocean
Michael J Gobell,
"Design, construction and testing of a semi-autonomous surface drifting buoy for coastal observations"
Dissertations and Master's Theses (Campus Access).