Marines with Motor Transportation Services Company, Combat Logistics Battalion 25 practice searching a water-fording navigation course at Camp Lejeune, North Carolina Aug. 13, 2014, during exercise Heavy Metal 14.Before the Marines entered the water, they were given a class on fording techniques and procedures, which explained the importance of knowing what is underwater. The Marines crossing are required to know if there are drop-offs concealed below the surface that could cause a vehicle to become inoperable.