Soldiers with 336th Engineer Company, tread water in the pool as part of their drown-proof training on Fort Hunter Liggett, Calif., Aug. 6, 2011. Drown-proofing classes teach Soldiers how to keep afloat and survive in the water. Soldiers are required to know how to tread water, float using natural buoyancy, perform various swimming strokes and use their Army Combat Uniform trousers as a makeshift flotation device. Soldiers of 336th Engineer Company participated in their annual training in support of Castle Installation Related Construction on Fort Hunter Liggett.