Underwater Altimeter to Protect Equipment

If the head of a vibrocore taking samples is driven too far it can touch the base. To eliminate the possibility of this happening, the US Army Corps of Engineers (USACE) is experimenting with the use of underwater altimeters attaching the altimeter's transducer to the head side of the vibrocore, the sonar transmitter to the base and aimed at the surface. As the sampling pipe is driven into the bottom and the head descends, the altimeter measures the distance between the upper and lower assembly.

Watching the altimeter's display, the operator knows exactly how deep the pipe has penetrated the ocean floor, and also the distance between the head and base. The machine can then be stopped before the two run into each other, preventing any damage.

Another group using the altimeter in an unusual application is EIC Laboratories, a research and development corporation in Massachusetts. EIC specialises in converting basic research into new products and processes. One of its newest products is a towed underwater instrument that uses a laser beam to locate oil spills in the water column and on the bottom. There is tremendous interest in using this device in the Gulf of Mexico in the wake of the BP disaster. Scientists at the lab have equipped their instrument with a UA-2 altimeter which inputs the exact distance from the sea floor to automatically focus the laser. Fishers SCAN-650 scanning sonar, which can "see" submerged oil, has been added to the equipment package along with a DDW-1 deep dive wing to assist in maximizing tow depth while minimizing the amount of tow cable required.