Navy ship meets UFO mother ship at sea.

I was a seaman aboard the USS Bronstein DE-1037 as a port lookout.  We had broken away from the carrier, as we often did.  We were on our way to North Viet Nam and going through the Philippine Sea when all of a sudden of to the starboard side of the ship the port lookout reported to me he saw something bright and big. 
I immediately stepped back and grabbed the big eyes, which are binoculars that are 3 ft. long and can see 18 mi.  What I saw was amazing.  It looked like a dirigible only it was over 2000 ft. long with a white cloud around the middle of it hovering over the water.  
As we got closer and closer to it, it was directly parallel to us.  It was a mother ship.  
As soon as the starboard lookout radioed to the bridge what he was seeing, it disappeared.  After it disappeared it left a round rainbow of red, yellow, blue and green.  
Then we pulled up beside it on the port side and I could almost reach out and touch it.  
The Navy officers were there with 8mm cameras filming it.  
It lasted for about 20 min. and dissipated.  After that there was no debriefing at all, and no scuttlebutt among crew members, which amazes me to this day.  Everyone went on about there daily duties as if nothing happened.  
It amazes me to this day that I never said anything, either.  
To the best of my recollection this is how it happened in 1971.
Witness indicates that the date is approximate.  PD