Ocean City, NJ, triangle of 3 lights, hovered over condominium, no sound, departed with incredible speed

It was late summer or early fall of 1978.  I was riding bikes around 8:00pm on the Ocean City, NJ boardwalk with a friend.  There were about 20 other people walking on the boardwalk.  At about 4th street, we all stopped to look at some extremely bright lights out in the ocean near Atlantic City.  In a matter of seconds, the lights were directly above the condominium complex at 4th Street and the boardwalk in Ocean City.  They were three lights in a triangle shape.  There was absolutely no sound.  We all just stood there in shock, looking up at the lights, trying to discern a craft or something.  The lights hovered there for about 10 minutes  Suddenly, the lights took off at an incredible speed in a southwest direction.  No one said anything - there was nothing to say because it was unexplainable.  I wish someone could explain this experience to me.
Witness indicates that the date of the event is approximate.  PD