black oval/circular object that did not reflect light spotted over Lake Cumberland - chase helicopter involved

I was googling "Lake Cumberland" + UFO and came upon your site with an identical sighting a decade earlier. 
Four of us were traveling on the lake at night on a boat and saw a helicopter following us.  What we did not see that came up alongside our boat was a an oval or circular shaped object (50 ft. elevation) that the helicopter (appeared to be Hughes 500 type) was obviously following 200 yds behind.  The craft made no apparent sound (as claimed by other sighting) and gave no reflection when we pointed our spotlight on the craft.  Both the object and chase helicopter flew off in the distance.  
We sat there for awhile stunned at what we had seen and had no plausible explanation.  The four of us are credible witnesses, one a former Marine, an accountant, a pilot and information specialist.  I was simply amazed at the identical sighting and have often wondered what we saw that night.
Witness elects to remain totally anonymous; provides no contact information.  PD