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Ballasting for Buoyancy

July 14, 2016

WHOI engineer Jared Schwartz “ballasts” an underwater glider to prepare it for a mission in the ocean about 100 miles off the southern coast of New England. Ballasting involves measuring the weight of the vehicle in saltwater to make sure it will be neutrally buoyant once at sea. Schwartz can change the glider’s weight by adding or removing copper-coated lead shot from ballast bottles in the fore and aft of the vehicle. Once deployed, the gliders, which have no propeller, fly through the water by using a syringe-like pump to change their volume—and therefore buoyancy—in the water. (Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)