Vessel operator stated that he had just taken the boat out for the first time this year and when he was approx 200 ft from his dock he smelled gas fumes.  He then immediately returned to his dock and turned off the engine.  After inspecting the engine compartment, he discovered that the ventilation hose wasn't properly connected.  He then connected the hose and turned the ignition at which point a fire erupted in the engine compartment.  Fire then spread too quickly to put out and engulfed the entire boat and part of the dock.  The vessel was almost entirely burnt, the vessel also sunk.
Spirit Lake                   