A large circular bright light appeared abruptly and stationary, for 10 to 20 minutes in front of the USS Vigor (MSO-473) at two in the morning.

Sighting happened 10 (ten) miles out at sea.  I had lookout duty from 0000-0400, on the bridge of the mine sweeper USS Vigor (MSO473).  I was a boatswains mate seaman at the time. Other observers included a lieutenant JG (also on the bridge); a  navigator seaman (on the bridge); a helmsman (one deck below the bridge); an engineman next to the helmsman operating the engines; and an after steering/lookout (engineman), on the fan tail.
The object appeared instantly; approximatly at a 45 degree angle in front of the ship and it looked about a hundred feet foward and one hundred feet from the water.  It was a huge light.  General Quarters was sounded and all personal went to battle stations. The light disappeared as abruptly as it appeared (10 to 20 minutes was how long the light stayed in front of the ship). 
This event was written in the log book as a UFO sighting.  Later that morning we were told that the airforce said that it was an experimental flare. (We were 10 (ten) miles out at sea, with no air craft or other ships in sight.
Witness indicates that date of sighting is approximate.  PD