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MAE 156B Spring 2012
SPAWAR OCEAN MONITORING VESSEL
Background
There is an expressed need among the oceanographic community (including SPAWAR, MBARI, SIO, University of Washington) to monitor the properties of ocean waters near the coast using a network of submersible buoys. Properties of interest include temperature, salinity, current, and conductivity. The buoys need to be able to withstand depths of up to 300 feet whilst logging and transmitting data from the onboard sensors.
Current buoy and glider type monitoring solutions exist, but at a cost of tens to hundreds of thousands of dollars per unit. SPAWAR wishes to design a buoy type ocean monitoring vessel that operates at a mere fraction of the current design solutions. New designs can utilize mass produced Android phones to replace expensive and bulky data logging and communications systems. Reduced size and weight result in a smaller vessel that is more resistant to pressure and cheaper to manufacture. The new buoys will be easier to deploy en masse and are ‘disposable’ in a sense that if they are irretrievable, the fiscal loss will be minimal.
Objective
The objective of the project is to design and fabricate an ocean monitoring spar buoy prototype that is able to operate in a saltwater environment in the laboratory. The most important requirement of this project is to make a low-cost and durable prototype that can be easily reproduced in the future. Functions that are expected on the monitoring vessel includes a working buoyancy engine for floating and sinking motion in saltwater, a corrosive resistant buoy body, a sensor system that is able to collect Conductivity, temperature, and depth in saltwater, and implementation of Android cell phone with the hardware for data collection, control of electronics and communication with the ground.
This prototype produced in this project will serve as a proof of concept for future product used in real world seawater environment near the shore for ocean monitoring activities.
Final Design
The Assembly CAD that shows all components is shown in the following figure:
Detailed Description can be found here
Performance Results
- Buoyancy test administered 6/7/12 to test the vessel’s ability to remain vertical while in motion and when floating
- Achieved average rising and sinking velocities of 0.18 and 0.19 m/s respectively (max theoretical velocity was 0.2 m/s)
- Vessel was able to remain upright for a prolonged period of time while being virtually unaffected by mock waves of sea state 3
(unaffected by sea state 4 at depth of 4 ft)
- Pressure test was successfully conducted
- 1MPa for 1 minute and repeated ten times to simulate sinking and floating.
- 2MPa for 1 minute meeting twice the design specification