I see this sometimes. Once I swam out to sea (from Padres I think) when I saw this and was able to jump on a Navy ship. DIdn't stay on of course - you only 'get on the deck' but as the ship moves you don't move with it so you fall off right away. Just like the frigate overboard glitch. By then I was way out to sea so I clicked a passing PC ship, whispered to the captain and he crewed me up - made a good friend that way :)

I notice that occasionally too.
I wonder if its part of the scenery or if it is a glitch that you actually see sea battles.

i see that all the time