Owner and his wife were on board relaxing when they smelled smoke before the 1st fire occured.  Owner opened a hatch near the steps to check the batteries and observed smoke. He called the fire department.  He then cut the power from shore side connection.  After the fire department put the 1st fire out the owner was pumping the water from the battery compartment when the batteries arched and started a 2nd fire.  Electrical system malfunction was cause of accident.
Boston                        