Force reconnaissance Marines with 4th Force Reconnaissance Company slide off F470 Combat Rubber Raiding Crafts into the water during hydrographic reconnaissance training at Marine Corps Training Area Bellows in Waimanalo, Hawaii, Jan. 13. The training was part of a weeklong jump and dive training package that brought the unit, headquartered in Alameda, Calif., together with their Hawaii-based counterparts — 4th Force's 4th platoon. "We are the tool our generals use to determine the geographical makeup of the land," said Petty Officer 2nd Class Mike Weissman, a hospital corpsman with 2nd platoon, 4th Force. "Before he makes the decision to execute a mission, the beach's gradient has to be surveyed. We come in clandestinely at night and make an underwater map of the beach for him."