It was about 4:15 in the morning in the third week in April of 1970 just prior to the Cambodian operation. We were on the YFU-79 on another ammo resupply run to Dong Ha and were making circles just off the mouth of the Song Cua Viet awaiting dawn so that we could safely clear the sandbars at the entrance to the river. Our position was approximately 16 deg & 55 min N Lat and 107 deg 15 min E Long. It was a clear night with a light wind. There were 4 of us on the duty watch. I was the helmsman and the boat's radioman. We had a deck seaman for our lookout, an engineman who was on the bridge with us, and the quartermaster was our Petty Officer of the Deck. We had done a couple of circles off-shore and when we came around on a heading back to the north-west, we suddenly saw this tubular object hovering over the DMZ close to the coast and south of the Song Ben Hai which is the river that splits the DMZ. The object did not appear to have any wings, a tail section or rotors. It was essentially a large tube-like object with red and white lights that could be seen along it's side. There was no engine noise that we could hear from it. The elevation was between 2,000 and 3,000 feet and we were perhaps 8 clicks south-east of the object. Abruptly, the object accelerated to the west at a very high speed and then just as suddenly came to a dead stop. My guess is that the object was now due north of the base at Dong Ha. It then slowly returned to the east, hovered near the coast for 2 or 3 minutes and then proceeded slowly on a north-easterly course out over the South China Sea where it disappeared from view. Red and white lights could be seen on the side of the object that we could observe. They didn't alternate colors but there were 2 or 3 reds and then a white light and gave the impression of being windows or some sort of aperture in the object through which the light came. The four of us on watch debated about whether we should enter the incident into the boat's log book but opted not to since we figured that we'd either be sent off to see psychologists or brought up on drug charges. We were very familiar with all types of aircraft and helicopters that operated over the DMZ. This object did not look nor behave like any aircraft we were familiar with at the time nor since.