The 2,200 dwt, 135-meter long freighter Onderneming IV went aground on the Rhine River nearDettenheim, Germany.   The vessel loaded with gravel veered onto the shallows when an oncoming vessel was out of its position in the traffic lane.  The Onderneming IV was unable to free itself.  Another vessel also attempted to pull the Onderneming IV free, but failed.   Reports state several hundred tons of cargo to lighten the vessel and a dredger will arrive to aid in freeing the ship.