RedactedNarrative: Operator had vessel cruising at 30 mph when he noticed a power loss.  She immediately stopped the vessel and shut off the engine.  A large column of black smoke was rising from the engine compartment.  Both occupants put on PFDs and jumped in the water.  Vessel sustained significant fire damage.  Cause of the fire was determined to be the ignition of a loose piece of trim that fell on the engine.