RedactedNarrative: A pontoon boat that had been changed into a houseboat was launched in the Suwannee River.  Soon after launching the operator stated he lost power due to water in the bilge, the bilge pump was inoperable.  the left pontoon filled with water and the vessel then capsized.  The operator and occupant swam to a friend's vessel and then attempted to right the pontoon, they were unsuccesful.  Once they tied the overturned pontoon to a marker they returned to the boat ramp and notified of the accident.  the vessel was recovered by commercial salvage company, no injuries reported.