I just watched the video on the Costa Victoria. That was a pretty ship.
I noticed you asked for comments & subscriptions at the very end of the video. Would it help to put this early in the video, while the most people are still watching?
Maybe you could have a short teaser explanation of what the video is about, then have a part where you say "Do you love ships and their stories? Click to subscribe so you can watch every video I make for you."
I bet people who are into this topic want more of your videos, and they will subscribe when you ask up front