The 31 meter long tugboat Al Deebel suffered an explosion and fire while off Qatar.  The tug was doing maintenance on a buoy that allowed liquid natural gas to be pumped into tankers when the buoy exploded.   Seven people on the Al Deebel were killed in the explosion with another four injured.   Only one crewman escaped unharmed.   The tug caught fire, but was able to be extinguished.   The tug was taken under tow back to Qatar where it will be inspected.   Authorities and the owners of the tug are conducting an investigation into the incident.