Disk shape object seen in Blue Hill Bay, Bass Harbor, ME , 1966

While going out to the fishing grounds, over Placentia Island Maine in Blue Hill Bay in Bass Harbor,my brother Frank and I saw a disk shape object which was dark in color and about the size of the space ship in the movie " Close Incounters of the Third Kind ".
The only light showing was a shaft of white light coming out of the center bottom.It was directed down upon the island of Placentia which was only inhabited by a man and his wife,Art and Nan Kellem (or Kellum).This was taking place at the SW section of the island.
When I flashed my running lights on and off the light from the object turned off.
My brothers responce was "Jesus,what is it !!!" We continued toward the fishing grounds and saw it light up again when we were about 2 miles South of it. It was at the same position as when we left.
We spoke with this witness via telephone, and we found him to be seemingly quite credible.  His recollection of the event was quite detailed.  The date of the sighting is approximate, but the witness reported that he thinks the sighting occurred in either July or August of 1966.  PD