Fire crews have extinguished a yacht fire in Northwest Miami-Dade early Sunday morning. Heavy smoke filled the air near the 3600 block of Northwest South River Drive. Fire rescue crews were at the scene putting out the flames. The boat fire has since been extinguished; however, the yacht was left a total loss. Units remained on the scene to contain fuel from the vessel and minimize environmental impacts. No injuries were reported. The cause of the fire is under investigation.