RedactedNarrative: Ofc's responded to the 500 blk of biscayne bay (miami beach) red a vessel fire. On miami beach marine patrol arrival ofc's observed a 21ft mako cc fully engulfed in flames. The captain of the vessel had jumped into the water and was picked up by vessel fast response was on scene and extinguished the fire without further incident.  Due to damage, a cause could not be determined.