It turns out to be a Chinese fishing fleet that cruises waters in the Arabian Sea / Gulf of Oman. They have these little boats that are about 100 feet long, and have large arrays of insanely bright lights to lure fish into their nets. In this case, they were well farther away from shore than normal, and right under our route.
I may have posted this before, so if so, apologies...
"Somewhere" in the Eastern Pacific, we were launched on a double-bag, day-into-night. Towards the end of the first bag, well after sunset and past nautical twilight, we were heading back to Mom and there appeared to be a GIANT city some miles ahead of Mom's PIM. We couldn't find anything specific on radar and asked if the ship saw it, which they confirmed. We weren't aided, so whatever this was, it was BRIGHT. As we headed to Mom to get gas, we all agreed that we needed to fly ahead of Mom and find out what the hell this thing might be.
After getting gas and launching, we informed Mom of our intentions, and there didn't seem to be an ounce of resistance. I think everyone wanted to know what this insane light ahead of us was. We decided to stay unaided, which was a smart move, in hindsight.
We chugged along for another 20-30 miles ahead of Mom (which shows how bright whatever this was, given we could see the bloom some 40 miles behind Mom). Finally we came across a fishing vessel that was lit up like a major city. Looking at it on FLIR showed these little "things" rotating about on the deck edge at equidistant positions, with lines going into the water. It was really weird.
Since it wasn't apparent what we were seeing made any sense, I decided to give them a call on BTB.
"Vessel at <position>, this is US Naval helicopter overhead."
"No....speak...Engrish."
"Roger, habla español?"
"No...speak...Engrish."
"Roger, you guys have a good night."
So, what the hell? Since it was night, we couldn't reliably read hull information, but it looked "local" (which later would mean from Costa Rica). Finally we landed, shutdown, and I went into Mx to do paperwork. My night-check Supe was waiting for me and I described what we saw. He was previously at a Japan squadron with lots of underway time in 7th Fleet.
His response: "Oh, yeah, that's a squid boat."
Me: "Huh?" (and then it was slowly coming together for me with the bright lights)
Him: "Yeah, they have the bright lights to attract the squid."
Me: "Oooohhhh. Yeah, that makes sense."
So, as was normal down there, you had a Costa Rican fishing vessel (probably with a Chinese name in a Maru class vessel), with Costa Rican nationals who were of Chinese descent. But this night, they were out squid jiggin'. It made complete sense.......after the fact.
But it was yet another chapter in the book of why Naval Aviation was an interesting profession.