RedactedNarrative: On July 6, 2014, at approximately 1356 hours, Lake Mead National Recreation Area Interagency Communications Center (LMICC) received a call from an employee at Willow Beach Marina.  The employee stated a vessel had sunk a few miles south of Willow Beach and the occupants were awaiting a Park Ranger at the Willow Beach Marina Store.  I responded, and made contact with the vessel owner and operator, who informed me him and his wife were traveling at approximately 20 mph north toward Willow Beach Marina when he could smell something burning.  He came down off plane and water immediately rushed forward into the vessel from the engine compartment.  As the vessel started to sink, OPERATOR and his wife donned life jackets before the vessel went under water.  OPERATOR jumped off the vessel into the water and began pushing the vessel toward the shoreline.  After tying the vessel to the shoreline the vessel remained vertical with only 2 feet of the bow above waterline.  OPERATOR contacted Vessel Assist and had the vessel salvaged/towed back to Cottonwood Cove Marina.  OPERATOR placed the vessel on his trailer and removed it from Lake Mead National Recreation Area.  The cause was a cracked exhaust pipe.