I like them, that’s why.
Funny thing: I don’t like the sea. It kind of frightens me.
I have been on a boat before. I’ve been on a ship. On the ship, I was small enough in comparison that I did not realize I was floating on an endlessly deep ocean that could swallow me whole. The boat I was on was more of a life-boat than a “yacht”. No matter where I sat, I could see water. That was a bit disturbing to me. I didn’t panic, but -ok I panicked on the inside. Anyway, this life-time, the vessels, sadly, have not been pirate-owned. So why do I like them? I think my previous statement may shed some light. “This lifetime” I do not have any pleasurable experience with boats/ships/the ocean, but hey… Whether you believe in past lives or not, I think most people can agree and have experienced feeling something so strongly though not knowing why. This is why I like pirate ships – spiritually I feel I have a connection to them. I think I was once a pretty bad-ass pirate. Like a Robin Hood of the sea kind of guy. Yes, guy.
Dinosaurs: Why not? Look at this guy:
Just for amusement’s sake, here is what a mix of the two things would look like: 
Robin Hood of the sea being chased by a T-rex. YES!
Pirate Ships and Dinosaurs 
Wicked. xD