In a future space navy universe that is heavily based on modern wet navies, would it be acceptable for a vessel XO (rank of Commander) to be field promoted to Captain from a single Fleet Admiral?

To add more context: the former captain is being removed from duty and placed under arrest for a major crime he committed. The XO had been investigating this and brought the information to an admiral. The XO has been an XO for about 4 years at this point, 2.5 of which has been on the current ship with the same captain. He is a highly decorated and admired officer among both the enlisted and the Admiralty.

I know field promotions tend to only happen in times of war, but the current world environment is a cold war era vibe.

More context: The star system is the Alpha Centauri system and the main navy is from the Republic around aCenA. The ship is essentially a flag ship as it is one of the most powerful cruisers that does long-duration solo missions on the outskirts of the Republic space that boarders the B-star space.

The XO was initially selected to command the ship but was rejected command because he was not a captain and still too young/inexperienced in some of the admirals eyes. He has since been the XO for 2.5 years, a few months of which he was acting captain as the main captain was on private leave (rebuilding his drug ring and saving his sons life because that is why he is in the drug ring to begin with). Basically there are a few admirals who want him to be the captain and some that don't.

While the 2 star systems (A and B) are not at war, there are several proxy wars going on and heightened tensions with several close-call events that could spark the inevitable war.

The Captains crime also link back to the murder of several crew members and other people outside of the ship.

Final Decision: Thank you everyone! Based on the input, I think it will be that the XO simply takes on the role of Acting Captain. The admiral could add something like once the ship makes port or at next leave he will be in for a promotion and a new XO for "his ship".

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    $\begingroup$ Traditionally, the XO would take command regardless of rank (that's part of the job). Also traditionally, the skipper is always addressed as "Captain" regardless of rank. $\endgroup$
    – user535733
    Jul 27 at 15:58
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    $\begingroup$ This is entirely dependent upon the rules of your particular space navy. Since you don't provide us any information about the rules for your space navy we cannot answer this question in any objective fashion. $\endgroup$
    – sphennings
    Jul 27 at 16:00
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    $\begingroup$ Field promotions are mostly a thing of land armies. Rank is mostly something which controls pay and pension and precious little else. There is zero reason to change the formal rank of a sailor just because a change in their role. $\endgroup$
    – AlexP
    Jul 27 at 17:43
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    $\begingroup$ If the answer is expected to be dependent on the context you've provided, then the question is too story-based. If you want us to help you develop the rules of promotion for your military, that's worldbuilding. If you want to know if it makes sense in the context of a single scene in your story, that's storybuilding and off-topic. Please edit your question to clear this up. Thanks. $\endgroup$
    – JBH
    Jul 27 at 20:46
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    $\begingroup$ This is a fundamentally story-based question: do you want this promotion to be unusual? I.e. the characters remark upon it, some don’t fully accept the XO’s authority, others may be impressed? Or would this just detract from the story you want to tell? There isn’t a clear-cut hard-science answer here, and you shouldn’t force your story out of its way for it. $\endgroup$
    – Ottie
    Jul 28 at 6:36

6 Answers 6


It's important to note that Navies, at least the US Navy and most NATO navies, make the distinction between "Captain" as a title (i.e. the commanding officer of a vessel), and "Captain" as a rank (in the US Navy that's O-6). For example, it's quite common for an officer with the rank of Commander, or even Lieutenant Commander in some cases, to be the Captain of a submarine or small vessel. Larger capital ships usually, but not always, have a captain in rank as the CO. For example, to be a captain of an aircraft carrier, one must be of O-6 rank and have been a former naval aviator.

A field promotion to Captain as a title is very much in an Admiral's discretion and quite common in the past. However, in most cases today, the CO is replaced with another officer of similar rank provided by the Navy as a replacement.

For example, in the USS Hartford incident, in which the CO, a Commander, was replaced with another Commander by the Rear Admiral of the group. A Rear Admiral is O-7 rank, which is relatively low as far as flag officers go. This could be considered a "field promotion," however, the replacing Commander was already the deputy commander of the submarine squadron, so it was more of a sideways transfer.

In the case of US Navy ships, it is far more common for them to fly in a new commander than "promote from within." This is because the Navy has a large backlog of officers waiting for the opportunity to command a vessel. It's also the reason why commanding officers are often relieved of duty for seemingly the smallest infractions. The Navy's thinking is it's "easier to replace a captain than replace a ship," given the huge talent pool of potential COs waiting in the wings and the relative availability of vessels to command. That's not to say a scenario like yours, where an XO is put in command out in the field, hasn't happened; it's just extremely rare (to the point of where I am unable to find articles detailing the cases I know about since I don't even remember the vessel's name). In any case, these types of field appointments are usually temporary, existing only long enough for the vessel to get to port or for the new commander to arrive.

A field promotion to captain as a rank is far less likely, as in general, promotions of rank are handled through a promotion board in which multiple officers have a say, and the candidate is compared to others under review (generally only a fixed number of officers can be promoted at a time, thus making it somewhat competitive).

That's not to say it can't happen, but it would generally only be during a time of war.

  • $\begingroup$ I dare saying that a lot depends on the environment. Your US NAVY example may be appropriate or suck depending on time. "The US navy prefers to fly in" is not necessarily a good approach when the next admiralty is half a year away with no fast means of communication to tell them to send someone - that would turn into a courier vessel taking half a year, then a replacement taking another half year. It works on the US navy as modern planes make "flying in a replacement" even vaguely practical. It would not work in the age of sail under all circumstances. $\endgroup$
    – TomTom
    Jul 30 at 16:16

Authority depends on communication.

The historical basis for the nearly unlimited authority of naval captains in the 17th and 18th centuries was the lack of communication with anyone higher who could respond to requests for clarifications of orders or requests for exceptions. Radio was nonexistent, messengers could take weeks to travel back and forth and frequently wouldn't make it at all. Out of necessity, decisions had to be made at lower levels than is typical today. If an admiral was available, then they could be consulted. If there was no admiral available, then the captain just had to make a decision and order his crew to execute it. Orders from higher-ups were, of necessity, more flexible than they are today because they had to contain room for unforeseen changes in conditions that were not predicted. Officers were trusted to make decisions consistent with overall strategic goals.

In your world, individual ships are out of communication with their fleet for weeks or months, and fleets are out of communication with Central Command for years on end. This could result from some combination of great distances, lack of reliable communication equipment, or long communications lag times. For example, perhaps the fleet in question is on the frontier of known space, having spent the last ten years traveling at its maximum speed of .9C. Even a light-speed radio message will take over 20 years to get a response, so the admiral must, of necessity, begin making decisions on who gets to command which ships without confirming everything with Earth.

Your Fleet Admiral is literally the highest level of authority that is aware of the incident with the former captain and is going to remain so for enough time to render any lack of action catastrophic. Your admiral thus decides that the best plan of action is to promote the XO to captain regardless of whether such a promotion is "recommended" or "typical" in that service.

In addition, the removal of the captain most likely also represents an expression of the field authority of your admiral. Since coordinating a trial with the folks at HQ would take upwards of twenty years and even sending them home would take up 10+ years and a valuable starship, the admiral must take charge and administer the trial right there in the field.

If, as you say, everything takes place within the same star system, this does not have to mean that communication is easy or quick. Perhaps there is a communications dampening field that makes reliable communication slow or unreliable, or perhaps your ships have need to maintain radio silence for purposes of stealth. If you can't radio back a request for permission to promote someone to captain, then you just have to promote them anyway.

  • 3
    $\begingroup$ Thanks for the answer. To clear some things up, there is no FTL transmissions or transportation in this universe. Everything happens in the Alpha Centauri system so communication can range from seconds to a couple hours. So there is fairly solid communication. This particular ship is a hunter class cruiser and the only one of its kind. So it's sort of the pride of the fleet. The XO has been groomed to be the captain once he was ready for it. $\endgroup$
    – Markitect
    Jul 27 at 18:37
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    $\begingroup$ So it is a lonely ship with the XO being next in line for command. COMMUNICATION would mean a field promotion makes no sense - you can easily ask HQ and get an answer. Would it be feasible to SEND a replacement? If yes - open. If not - the XO must literally take command. It he already was groomed (possibly for the next similar ship to be built), unless politics play crazy, he will get the command. Anyhow there is no field promotion as communication is short enough to ask HQ. And the XO is interim in charge regardless of rank due to his position as XO anyway - that is his job. $\endgroup$
    – TomTom
    Jul 30 at 16:20

Field promotions occur when the chain of command is broken or untrustworthy.

If your setting allows for rapid communications across the entire range of your story then I would say 'no', field promotions are not going to be a thing. On the other hand, if messages have to b physically carried then it is likely that such promotions will be a normal part of your force's operations.


Even with poor communication, unless the vessel involved is a major fleet asset (capital ship, as it were -- in today's terms an aircraft carrier or submarine, or as late as the 1940s a battleship or heavy cruiser, but not a sub), there's no reason it must be commanded by a Captain in rank.

As noted in comments to the question, whoever commands the vessel will be called "Captain" by the crew, officers and ratings alike, but Captains of destroyers and frigates (and subs, prior to the missile boat era) were often Lieutenants and rarely higher ranked than Commander.

Also worth noting that traditionally, the former ship's Captain (holding Captain's rank) will be addressed as "Commodore" while still aboard ship and awaiting court martial, or when aboard any other ship. A ship can have only a single Captain, regardless of rank, and he technically outranks anyone who doesn't hold the actual rank of Commodore or Admiral while aboard his own ship -- even if that person would outrank him when ashore -- and even those ranks have no authority over him aboard his own ship unless they're in his chain of command.

So I believe it likely that your XO, who probably holds the rank of Lieutenant or Commander, will remain in his existing rank while acting as Captain, and will be listed in the rolls as "acting Captain" even while being addressed as "Captain" for all purposes while in command.


First, keep in mind that personnel selection and promotion are key to ultimate control over the military. Who can reward loyalty and punish disloyalty? In a society like the modern West, there is civilian control over the military.

You have to think about the balance in your fictional society. Probably the "military establishment" has control over entrance and promotion of junior ranks. Probably the "government" (democratic or otherwise) has control over the seniormost ranks. Where a captain falls in this scheme is up to you. You could have a system where only admirals have to be confirmed by parliament, and where those confirmed admirals then get to promote less-than-admiral ranks. Or you could have a system where every ship commander must be confirmed by civilian oversight. (Does it make sense in your story to separate starships from insystem ships, and require confirmation for the former but not the latter?)

Second, command should fall to the XO when the captain is unavailable, without requiring special promotions or orders. That's part of the role of the XO. So the Fleet Admiral could simply message that he or she has full confidence in the XO, and fail to send a replacement from the flag staff. (If the admiral is a Fleet Admiral, there might be lower-grade admirals or at least captains as chief of staff, operations officer, intelligence officer, etc. Check the About Us section of the 6th Fleet, five admirals.)

If you combine this with civilian confirmation requirements, possibly the XO of a starship needs to be confirmed as well, which would make him "pre-cleared" for the position of captain, thereby easing your desired plot.

But finally, the admiral should consider what it does to the morale and unity of command to promote a whistleblower/backstabber who might have to testify against the former commander into that commander's slot. Klingon promotions are not a good habit for a navy.


It would not be crazy for the XO to be promoted to captain and also for another officer to be promoted to XO. These could be 'acting' titles. This would happen when travel is slow compared to distances involved. For example, if a ship is 3 months out, or being 'dark', then someone must fill the role of captain.

In WW2, consider a submarine where the captain dies of a heart attack just as they get to their patrol area. They aren't going to become a democracy because there's no captain. The XO takes over, someone else fill the XO role, and so on. If they report in, they may be told to stay on patrol, or to head in for a new captain.

If travel is near-instant then a new Captain can show up anytime and there's no point to a field promotion.


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