When is a Navy Captain referred to as 'Commodore'? When is a Lieutenant called 'Captain'?

Thanks for tagging me SN Greg Wright. I am thankful for the US Navy veterans who provided the answers since I did not know any of them. :-)

Have you ever heard of the UNITED STATES COAST GUARD???

1. If they command multiple squadrons or separate commands.
2. If he's in a major's billet, thus wearing that rank, but not afforded the actual promotion yet.
3. When they command a sea-going vessel.

Bonus: A boatswain's mate.
Bonus bonus for 2: When he's singing a key that isn't minor.

1. When he is in Command of a Squadron of Ships.
2. I'm clueless.
3. That is easy my Uncle WWII Veteran was an E-3 Captain. Senior Man in Charge of a Naval Vessel in my Uncles Case a Landing Craft.
4. Boats, Senior Boatswains Mate onboard a Naval Vessel is Called Boats. Or Boatswains Mates in General. I had some Damn Good Boats take care of this Crippie.

My son was first in Navy from long line of mostly Air Force family. But Army was previous years going back to WW1 and even AR. I have learned a lot about the Navy from him and history never knew.

Good quiz. I have to say I enjoy learning all the odd things that people post about the branches.

Here's one for you Greg.
When is the only time that a Naval Officer will be referred to as Chief?

1) An O6 on a vessel not acting as the Captain of said vessel, such as the ARG Commander.
2) Out of vogue now, but when you have non-Navy O3 aboard (in small quantities), they "may" be referred to as "Major" as a ship only has a singular Captain. Reference Starship Troopers by R.A. Heinlein for the tradition.
3) The Captain of a ship, as a position of authority. Although "Skipper" may also be appropriately because of Rank. My understanding was Commander+, but it's been a long time since I looked at it.

LOL, you got me on those. No clue.
Just reading Billy Budd again, I figured out where the term Midshipman came from.

SN Greg Wright another amusing thing in ranks, is the differences in the meaning of "Chief". In the Navy and Coast Guard, E-7. In the Army, CWO. In the Air Force, E-9...

1. When he is in charge of a CTF or a Group.
2. Umm when he's a major pain in the ass?
3. When they are the CO of a ship.

Here's one for you:
Your ship is expecting a number of dignitaries; among whom are going to be the Captain of the USS United States and the PotUS.

The bells ring and you hear over the 1MC, "United States, Arriving" ... how do you know if it's the Captain or the President?

Some mistakes below:
Item 1) A Captain is referred to as Commodore when he leads multiple commands, not just ships. Commodore of NBG-1 has multiple shore commands under him/her, such as BMU-1 ACU-1, ACU-5, ACB-1.
Item 4) "Boats" is a short name for a Boatswain's Mate (BM). Also, a Ship's Boatswain (a Warrant Officer Specialty) will be referred to as "Boats" but ONLY by his Warrant peer group or the CO/XO.

I've always heard it explained thus-but am open to correction:

1. The rank of Commodore was created during the time when there were only three ranks of fully qualified naval offices...Lieutenants, Captains and Admirals. A lieutenant was any officer who had passed the examination after serving as a midshipmen. Captains were officers commanding ships, and Commodores were Captains who commanded flotillas, but didn't share equal rank with general officers ashore. An admiral was essentially a general at sea, commanding vessels, and embarked troops.

2. I believe historically, any time a lieutenant assumed command of a vessel permanently, he was promoted "captain". The rank of Lieutenant-Commanding was created later to signify a lieutenant who was fully in command of a vessel, and by the 19th century, this rank evolved into Lieutenant Commander. Rear Admiral evolved to replace Commodore...though I believe (and I'd need to do some fact checking) the term continued for a short time as the ranks of Captain and Rear Admiral distanced in status and became more formalized.

3. "Boats" of course, has been used for at least two occurrences...first, as the Boatswain's Mate; a billet that extends back to the earliest days of sail, and continues today as the senior enlisted or warrant officer under the First Lieutenant. Most usually, the most experienced and qualified person above decks. I've also heard it used commonly in the second instance, among any rated Boatswain's Mate-thought I'd love to get the "official" take from any BMs on RP.

In summary, the term "commodore" has always indicated an officer who has command over more than one vessel...but I believe the use fell away with the increased formality of progression from Captain to Rear Admiral. A Lieutenant commanding a vessel as senior officer would be called "Skipper", but with the emergence of Captain as a formal rank, and Lieutenant Commander, I do not believe you would call a senior LT in command "Captain". "Boats" is most probably best applied to the First Lieutenant's senior enlisted/warrant officer expert...though I have heard it used in-rate by BMs.

SN Greg Wright
1. When said Captain is in charge of a group of ships; ARG, CSG, etc.
2. Never heard that one. I've seen others say that an O3 Captain is called Major to avoid confusion when onboard a Naval vessel but I've never seen it. I've had Jarheads on a few of my ships and their O3's were always called Sir/Ma'am or Captain.
3. When they're the commanding officer of a ship or small boat.

Bonus: A Boatswain's Mate, duh! :)

Haha...I served in the Corps, so i'll take a stab at these.
1. when the cap-e-ton is in charge of more then one ship, I believe.
2. I would say Never. I've been on naval vessel and we never called our Capt, Major, we just called him Sir. We called the Captain or Full Bird- Skipper.
3. When he's in charge of a vessel
bonus - boatswain

I lived in Annapolis for five years and Pearl Harbor for two. My dad worked for the Navy for 20 some years. I still don't get it all. I was gonna join the Navy but I figured at 6'6" I'd kill myself hitting my head on pipes and things. I think I made the right choice. Just figuring out all the rank would have been too much for my simple mind.

I thought a Commodore was a one star.

If you are Russell Crowe or in Pirates of the Caribbean.

1. 06 "Commodore": command of more than one ship but less than a fleet (or he would be an admiral).
2. 03 "Major" a courtesy promotion to a Marine Captain serving aboard a vessel where referring to him by his proper rank may confuse folks vs. the commander of the vessel (the Captain)
3. Navy 03 or SCPO or MCPO as 'Captain" when he routinely has command of a vessel (patrol boat, Coast Guard boats, etc.)

And I did answer these without reference or looking at the the other answers first.

1. Commander of a ready group. examples: DESRON, PHIBRON, TACGROUP
2. no idea, never heard of an O-3 called a Major (O-4 in all other branches)
3. When he is the ONC of the vessel. Normally called Skipper.
4. Someone in the Boatswain Mate rate (PO3 and above) The senior Boatswain Mate on the ship are also know as God.