(Note: This is NOT an official United States Government website)
The Continental Congress established the Continental Navy on October 13th, 1775. That is recognized as the official birthday of the United States Navy.
The ensign is the term used to describe the national flag flying at the fantail of a U.S. Navy ship. Navy protocol requires sailors to salute the ensign when they board or disembark from a Navy ship while they are in uniform. Sailors not in uniform, including retired sailors, will typically at least turn towards the ensign and stand momentarily at attention when they board or disembark.
All Navy recruits go thru "Boot Camp" at the Recruit Training Command (RTC) in Great Lakes, Illinois. Some sailors wryly refer to it as "Great Mistakes."
I'm not sure there is a really good answer to this question -- one of the better ones I've heard is that a ship is a vessel that travels on the open ocean autonomously whereas a boat is generally carried on another (larger) vessel for long trips. If you put it on another vessel it's a boat, in other words. (the USS Cole being a notable exception)
Start here: http://www.navy.com/ or visit your local Navy recruitment office.
E1 - Seaman Recruit
When you first report to RTC ("Boot camp") this is your rank. There is no insignia for it.
E2 - Seaman Apprentice
E3 - Seaman
E4 - Petty Officer, 3rd Class
E5 - Petty Officer, 2nd Class
E6 - Petty Officer, 1st Class
E7 - Chief Petty Officer
Being a Chief is a big accomplishment for Navy enlisted. It has its privileges and responsibilities. Chiefs generally have their own mess and galley on ship as well as their own bunk rooms separate from the other enlisted. Its generally accepted that in the Navy, Chiefs are the ones who really run the ship.
E8 - Senior Chief Petty Officer
E9 - Master Chief Petty Officer (note that there are a few variations on this rank - not all Master Chiefs are equal)
O1 - Ensign
O2 - Lieutenant Junior Grade
O3 - Lieutenant
O4 - Lieutenant Commander
O5 - Commander
O6 - Captain
O7 - Rear Admiral, Lower Half
O8 - Rear Admiral, Upper Half
O9 - Vice Admiral
O10 - Admiral
Fleet Admiral (doesn't have an "O" designation)
2.2.1 John Paul Jones
2.2.2 Admiral Chester Nimitz
Fleet admiral during WWII. He signed the Japanese surrender treaty on behalf of the United States of America.
2.2.3 Admiral William "Bull" Halsey
2.2.4 Admiral Hyman G. Rickover
2.2.5 Rear Admiral Grace Hopper
Both, actually. In the Navy "Captain" is both a rank (O6) and a title. You can be a Captain (O6) without commanding a ship and you can gain the title of Captain without attaining the rank of Captain. A ship's commanding officer is always referred to as the "Captain" of the ship but not all of them hold the rank of Captain. In fact, many ship's commanding officers in the U.S. Navy only hold the rank of Commander (O5)or even below. Generally speaking the bigger and more important your ship is the higher the rank you have to attain if you want to command it.
The USS Missouri was commanded by 20 different men during her career and only two of them did not hold the rank of Captain -- they were both Commanders who were serving as the Executive Officer ("XO") and took over command of the ship due to extraordinary circumstances that rendered the Captain unable to serve. In the first case Captain Brown was relieved of command after running the ship aground and Commander Peckham took command for four days until Captain Smith arrived to take command. In the second case Captain Edsall suffered a heart attack and passed away on the bridge of the ship and Commander North took command for about 8 days until Captain Brodie came aboard.
The captain of a ship is often referred to as "The Old Man" by the crew, regardless of his (or her!) actual age or rank.
No, the last one was USS Missouri.
Too expensive to run them, mostly. The modern navy is mostly about missiles and aircraft -- a battleship is primarily a gunnery platform. While the Iowa-class battleships were modernized to carry missiles the modern cruisers, destroyers and even submarines will bring at least as many missiles to the battle with quite a lot fewer crewmembers.
Aircraft carriers. Approximately 1100 feet long, more than 90,000 tons in displacement.
3.1.1 USS Constitution
Old Ironsides. One of the six original frigates built for the United States Navy in 1796.
Official Website: http://www.ussconstitution.navy.mil/
3.1.2 USS Arizona (BB 39)
A WWI vintage Pennsylvania-class battleship, USS Arizona was sunk during the Japanese attack at Pearl Harbor on 12/7/1941 going down with more than 1177 of her crew lost.
3.1.3 USS Missouri (BB 63)
One of the world's most famous battleships USS Missouri was the site where the Japanese signed the formal surrender that ended World War 2. Large, fast and powerful she served in three wars before finally being retired for good (we hope) in 1992.
3.1.4 USS Enterprise
"The Big E" there have been several ships named "Enterprise" in the history of the Navy. All of the recent ones have been aircraft carriers.
3.1.5 USS Nautilus (SSN-571)
The first nuclear submarine in the U.S. fleet.
3.1.6 USS Monitor
An aircraft carrier is more or less what the name implies -- a huge floating airport.
Varies a bit depending upon the carrier and the type of aircraft but the Nimitz-class of aircraft carrier (the main carrier of the U.S. Navy today) carries 80+ aircraft.
Traditionally the heaviest and most heavily armored ships are designated "battleships" -- they are the ships that would lead a line of battle during the 19th century.
BB is the United States Navy's designation for "Battleship." The navy always uses at least two letters in their designations; hence DD for destroyer, SS for submarine, etc. Today there are more designations and they are often more than two letters; such as SSBN for ballistic missile nuclear submarines.
Frigates evolved from what used to be called "Destroyer Escorts." The fill primarily an escort role in the navy, conducting anti-submarine warfare and some limited missile operations. They are very cost effective and tough ships but there aren't very many of them still in service today -- in many cases the faster and more capable (though more expensive) destroyers have taken over their role.
Only as a joke. Modern frigates only make 29 knots or so, making them among the slowest of the combat ships. Even USS Missouri, the WWII era battleship, is faster. The navy doesn't use single-letter designations (see 3.31) so FF stands simply for "Frigate."