Interesting. I do have pic's of that, probably, the same sub off of Oahu. I think we saw this hanging out Tracks Beach area for about a month before the missile fiasco. You could tell they were comfortable in being in the waters as the crew were sitting on top of the sub. We just thought they were coming up for air and enjoying the beautiful day.
Westside of Oahu off of Tracks Beach.
I took these photo's in Oct of last year. It hung around for quite awhile. Same area around Tracks Beach.