Oceanographic profiler for shallow water

This paper is a detailed explanation of the design and development of a small, inexpensive oceanographic profiler. The profiler is easy to deploy and recover, is expendable, and can be deployed in large quantities over a broad area to take synoptic measurements. The profiler uses a ballast tank, altering buoyancy to descend and ascend. To detect the pressure at the maximum depth of 50 meters, a simple pressure switch is used. At 50 meters the pressure creates a force great enough to puncture a pressurized 12-gram CO/sub 2/ canister. The pressurized gas feeds into the ballast tank forcing the water out, and the now positively buoyant profiler ascends to the surface. Testing showed that the descent rate could be controlled from 3 to 20 centimeters per second by adjusting the net weight of the device. Also the pressure switch worked at a range of depths with an accuracy of 5 meters, before returning to the surface. A rod with a foam ball, painted international orange, attached to the top of the device allows easy recovery in relatively calm waters. This ball is suspended approximately 45 centimeters above the surface when the profiler returns at the end of a deployment. The prototype is a flexible platform that can accommodate a variety of payloads and descent rates.