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?
USS Triton (SSRN-586)
USS "Triton" (SSRN/SSN-586) was a United States Navy radar picket nuclear submarine. In early 1960, it became the first vessel to execute a submerged circumnavigation of the Earth in Operation Sandblast. "Triton" accomplished this objective during her shakedown cruise while under the command of Captain Edward L. "Ned" Beach, Jr. She was the only member of her class and had the distinction of being the only Western submarine powered by two nuclear reactors.
"Triton" was the
Navy
A navy or maritime force is the branch of a nation's armed forces principally designated for naval and amphibious warfare; namely, lake-borne, riverine, littoral, or ocean-borne combat operations and related functions. It includes anything conducted by surface ships, amphibious ships, submarines, and seaborne aviation, as well as ancillary support, communications, training, and other fields. The strategic offensive role of a navy is projection of force into areas beyond a country's shores (for example, to protect sea