The 274 meter long tanker Naticina collided with a barge on the Houston Ship Channel.   The towboat Alliance was towing the barge, loaded with 20,000 barrels of xylene, when the barge struck the tanker.  The Naticina suffered damage to its hull with a breach to its stargobard ballast tank.   No injuries or pollution released.   Authorities are conducting an investigation and conducting surveys for damage.