I'm in the Navy.  Have you ever been in the military? 
No I haven't but I know that the navy or maritime force is waterborne military watercrafts.
What are your favorite ships in the Navy? 
There are so many to choose from like submarines, surface ships, amphibious ships, and seaborne aviaton.
Pick one that you like the most. 
Okay, i like the submarine most. It's a watercraft that operates underwater.
Have you ever visited a submarine? 
I have when I was on vacation once. The USS "Triton". It was the first vessel to completely circle the Earth.
Was it a nuclear submarine? 
Yes, it was a US Navy radar picket nuclear sub.